Chinese Journal of Radiation Oncology

中华放射肿瘤学杂志

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Chinese Journal of Radiation Oncology

	2015 Vol.24 Issue.2 Published 2015-03-30

	Orignal Article

Orignal Article

	101	Postoperative adjuvant three-dimensional conformal radiotherapy improves long-term survival in patients with pathological T_2－3N₀M₀ esophageal cancer
		Yang Jinsong, Zhang Wencheng, Xiao Zefen, Zhou Zongmei, Zhang Hongxing, Chen Dongfu, Feng Qinfu, He Jie, Gao Shugeng, Sun Kelin, Liu Xiangyang, Fang Dekang, Mu Jyuwei, Wang Dali
		Objective To assess the clinical value of three-dimensional conformal radiotherapy (3DRT) in postoperative adjuvant therapy after initial radical surgery for pathological T_2－3N₀M₀ thoracic esophageal squamous cell carcinoma (pT_2－3N₀M₀ TESCC). Methods The recurrence, survival, and radiotherapy adverse events in 96 patients with pT_2－3N₀M₀ TESCC who received adjuvant 3DRT after radical surgery from a prospective nonrandomized phase Ⅱ clinical study from 2004 to 2011 were compared with those in 820 patients undergoing surgery alone. The survival rate was determined by the Kaplan-Meier method and analyzed using the log-rank test. Multivariate prognostic analysis was performed using the Cox proportional hazard model. Results Postoperative 3DRT group had a significantly higher ratio of patients with tumor length ≥5 cm and stage T₃ than surgery alone group. The 5-year sample sizes for the postoperative 3DRT and surgery alone groups were 35 and 270, respectively. The 5-year overall survival (OS) and disease-free survival (DFS) rates for the postoperative 3DRT versus surgery alone group were 74.3% vs. 59.9%(P=0.010) and 71.0% vs. 51.7%(P=0.002), respectively. Multivariate analysis revealed that 3DRT was independently associated with an improved OS (P=0.030) and DFS (P=0.004). The overall recurrence rate, locoregional recurrence rate, and distant metastasis rate in the postoperative 3DRT group versus surgery alone group were 22.9% vs. 43.0%(P=0.000), 18.8% vs. 35.2%(P=0.001), and 11.5% vs. 21.3%(P=0.024), respectively. Both early and late grade 3 adverse events developed in 25 patients (26.0%) in the postoperative 3DRT group. Conclusions Compared with surgery alone, postoperative adjuvant 3DRT reduces the recurrence rate and improves the 5-year DFS and OS with tolerable adverse effects in patients with pT_2－3N₀M₀ TESCC. Prospective randomized phase Ⅲ clinical study is still needed.
		2015 Vol. 24 (2): 101-105 [Abstract] ( 4143 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	106	Survival comparison of three-dimensional radiotherapy alone with concurrent chemoradiotherapy for non-surgical esophageal carcinoma
		Tan Lijun, Xiao Zefen, Zhang Hongxing, Chen Dongfu, Feng Qinfu, Zhou Zongmei, Lyu Jima, Liang Jun, Yin Weibo
		Objective To compare the survival between three-dimensional radiotherapy (3DRT) alone and concurrent chemoradiotherapy (C+3DRT) for non-surgical esophageal carcinoma. Methods Four hundred and eighty patients with esophageal squamous cell carcinoma who were treated with definitive 3DRT or C+3DRT in our institution from 2002 to 2012 were collected and 296 out of them were equally divided into 3DRT group and C+3DRT group. Survival comparison between the two groups was made by propensity score matching method. Patients were mainly given paclitaxel and platinum weekly in C+3DRT. Results The numbers of samples at 3 and 5 years were 58 and 48 in the 3DRT group, and 58 and 52 in the C+3DRT group. The 3-and 5-year overall survival (OS) rates were 32.6% and 22.1% in the 3DRT group, and 35.1% and 26.5% in the C+3DRT group (P=0.463).The 3-and 5-year progression-free survival (PFS) rates were 27.8% and 19.8% in the 3DRT group, and 30.7% and 25.8% in the C+3DRT group (P=0.637). In the 3DRT and C+3DRT groups, patients treated with 60.0－70.0 Gy had similar OS rates (25.6% vs. 25.3%, P=0.833), PFS rates (22.7% vs. 25.2%, P=0.999), and incidence rates of hematogenous metastasis (23.4% vs. 24.1%, P=0.899) at 5 years. Patients treated with 50.0－59.9 Gy had significantly higher 5-year OS and PFS rates in the C+3DRT group than in the 3DRT group (32.3% vs. 12.0%,P=0.030;24.1% vs. 10.6%,P=0.087). In the 3DRT group, patients treated with 60.0－70.0 Gy had significantly higher 5-year OS and PFS rates than those treated with 50.0－59.9 Gy (P=0.024,P=0.041). In the C+3DRT group, patients treated with 60.0－70.0 Gy and 50.0－59.9 Gy had similar 5-year OS and PFS rates (P=0.791,P=0.984). The incidence rates of adverse reactions, such as esophagitis and leukopenia, in the C+3DRT group were significantly higher than those in the 3DRT group (P=0.000,P=0.005). However, those adverse reactions could be tolerated by patients. Conclusions For patients with non-surgical esophageal carcinoma, a low dose in definitive C+3DRT is recommended. 60－70 Gy in 3DRT alone can also achieve a promising survival in patients who cannot receive C+3DRT, which still needs to be confirmed by randomized studies.
		2015 Vol. 24 (2): 106-110 [Abstract] ( 3809 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	111	Prognostic analysis of radical 3DRT±chemotherapy in patients with esophageal cancer aged 70 years or older
		Li Xue, Zhang Wencheng, Zhao lujun, Cao Qinchen, Wang Peng, Wang Ping
		Objective To evaluate the efficacy and adverse effects of radical three-dimensional conformal radiotherapy (3DRT) alone or combined with chemotherapy in elderly patients (≥70 years) with esophageal cancer. Methods The clinical data of 116 esophageal cancer patients who were aged 70 years or older and received radical 3DRT±chemotherapy from 2008 to 2013 were retrospectively analyzed. Of the 116 patients, 32 received concurrent chemoradiotherapy, 24 received sequential chemoradiotherapy, and 60 received radiotherapy alone. Overall survival (OS) and progression-free survival (PFS) rates were determined using the Kaplan-Meier method, and survival difference analysis and univariate prognostic analysis was performed using the log-rank test. Multivariate prognostic analyses were performed using the Cox proportional hazard model. Results The follow-up rate was 100%. The 2-and 3-year sample sizes were 102 and 77, respectively. The 1-, 2-, and 3-year OS rates were 59.1%, 38.4%, and 23.2%, respectively, and the PFS rates were 61.9%, 37.9%, and 0%, respectively. The median OS for the patients treated with concurrent chemoradiotherapy, sequential chemoradiotherapy, and radiotherapy alone were 22.3, 18.0, and 12.4 months, respectively (P=0.044). The median OS was significantly different between patients treated with 60 Gy and<60 Gy in radiotherapy (24.7 vs. 10.9 months, P=0.036), but not significantly different between those treated with 60 Gy and>60 Gy (24.7 vs. 18.7 months, P=0.938). Multivariate analysis indicated that sex, presence or absence of combined chemotherapy, and radiotherapy dose were independent influencing factors for OS (P=0.003, 0.042, and 0.037, respectively). Conclusions Radical 3DRT±chemotherapy are well tolerated in elderly patients with esophageal cancer and equally effective as in those younger than 70 years. Patients treated with radical concurrent chemoradiotherapy have a better prognosis than those treated with sequential chemoradiotherapy and radiotherapy alone. Radiotherapy with a dose of 60 Gy effectively improves the survival compared with doses less than 60 Gy, which suggests that 60 Gy is the optimal dose in radiotherapy.
		2015 Vol. 24 (2): 111-115 [Abstract] ( 2486 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	116	Impact of contrast-enhanced 4DCT scan on delineating GTV and constructing IGTV in thoracic esophageal cancer
		Wang Jinzhi, Li Jianbin, Qi Huanpeng, Zhang Yingjie, Wang Wei, Ma Zhifang, Ding Yun, Shang Dongping
		Objective To investigate the difference between conventional and contrast-enhanced four-dimensional computed tomography (4DCT) scans in delineating the gross tumor volume (GTV) in different phases and constructing the internal gross tumor volume (IGTV) in primary thoracic esophageal cancer. Methods Twenty-five patients with thoracic esophageal cancer, including 8 upper-thoracic, 9 middle-thoracic, and 8 lower-thoracic, sequentially underwent conventional and contrast-enhanced 4DCT scans during normal breathing. The GTVs were delineated by a physician under the same standard using conventional plain 4DCT images, and the IGTVs were constructed accordingly. After one month, the GTVs were delineated by contrast-enhanced 4DCT images and IGTVs were constructed by the same physician. Results The coefficient of variation for the target volume based on the contrast-enhanced 4DCT images was smaller than that based on the plain 4DCT images. There were no significant differences in the length of the z axis of GTV, GTV, and IGTV between contrast-enhanced and plain 4DCT images in patients with upper-and lower-thoracic esophageal cancer (P=0.529 and 0.110;P=0.158 and 0.416;P=0.147 and 0.615). However, in patients with middle-thoracic esophageal cancer, the length of the z axis of GTV, GTV, and IGTV were significantly different between contrast-enhanced and plain 4DCT images (P=0.005, 0.035, and 0.021, respectively). Conclusions Contrast-enhanced 4DCT scan can reduce the error in delineating the target volume and construct a more accurate IGTV for patients with middle-thoracic esophageal cancer. However, it has no significant benefit in patients with upper-and lower-thoracic esophageal cancer.
		2015 Vol. 24 (2): 116-120 [Abstract] ( 2682 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	121	Analysis of correlation between GTVs delineated based on SUVs of PET-CT and EE phase of 4DCT in thoracic esophageal cancer
		Guo Yanluan, Li Jianbin, Li Fengxiang, Ding Yun, Liu Shanshan, Duan Yili, Shang Dongping, Fu Zheng
		Objective To investigate the correlation factors in delineating the gross tumor volume (GTV) of primary tumor in thoracic esophageal cancer based on the positron emission tomography-computed tomography (PET-CT)(thresholds of standardized uptake value or SUV ≥2.0 and ≥20% of maximum SUV or SUV_max) and the end-expiration (EE) phase of four-dimensional computed tomography (4DCT). Methods Twenty-two patients with thoracic esophageal cancer sequentially underwent 3DCT, 4DCT, and F-fluorodeoxyglucose PET-CT for thoracic localization. GTV_50% was delineated by the EE phase of 4DCT. The internal GTVs based on PET-CT images (IGTV_PET) were delineated by two thresholds:SUV ≥2.0 and ≥20% of SUV_max, and designated as IGTV_PET2.0 and IGTV_PET20%, respectively. The maximum transverse diameter of GTV_50%, volume of GTV_50%, the displacement in cranial-caudal (CC) direction, 3D motion vector, and SUV_max were obtained. Results The maximum transverse diameter of GTV_50%, volume of GTV_50%, the displacement in CC direction, and 3D motion vector showed no significant correlations with the volume ratio (VR) of IGTV_PET20% or IGTV_PET2.0 to GTV_50%(P=0.055- 0.932), but showed significant correlations with the conformity index (CI) between IGTV_PET20% or IGTV_PET2.0 and GTV_50%(P=0.005- 0.033). Significant correlations were observed between the VR and CI of IGTV_PET20% to GTV_50% and SUV_max(P=0.001 and 0.016, respectively). Conclusions IGTV based on PET-CT images cannot objectively and accurately reflect the changes in spatial position and motion of the tumor, and the selection of a single SUV threshold is unreliable. To determine the primary tumor target in esophageal cancer, the IGTV based on 4DCT should be used to correct the boundary and position of IGTV constructed based on PET-CT.
		2015 Vol. 24 (2): 121-125 [Abstract] ( 3214 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	126	Comparison of target dosimetry and treatment outcome in patients with stage Ⅲ non-small cell lung cancer treated with three-dimensional conformal radiotherapy and intensity-modulated radiotherapy
		Wang Yuxiang, Tian Xiuming, Qiu Rong, Wang Lili, Zhu Shuchai
		Objective To compare the target dosimetric distribution and clinical outcome in patients with stage Ⅲ non-small cell lung cancer (NSCLC) treated with three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT). Methods The clinical data of 419 patients with stage Ⅲ NSCLC treated with either 3DCRT or IMRT were retrospectively analyzed. Among them, there were 338 male and 81 female patients, and the median age was 63 years (range:32－84 years). There were 340 patients treated with 3DCRT and 79 with IMRT, and the median prescribed dose was 60 Gy (range:50－76 Gy). One hundred and forty patients were treated with radiotherapy alone and 279 were treated with chemoradiotherapy. The target dosimetric distribution was evaluated with dose-volume histogram (DVH) parameters. The overall survival (OS) rate was calculated using the Kaplan-Meier method and analyzed by the log-rank test. Results When comparing the clinical data, the patients treated with 3DCRT were in older ages, and had advanced N and clinical stages (P=0.01, 0.00, and 0.00, respectively). When comparing the target DVH parameters, the patients treated with IMRT had larger planning target volume (PTV)(P=0.01), significantly lower clinical target volume (CTV) D_mean, CTV D₉₀, PTV D_mean, and PTV V₆₅-V60(P=0.05－0.01), significantly higher V₅-V₂₀ in both lungs, higher esophagus D_mean, longer esophagus in the radiation field, higher linear energy transfer between 45 and 55 keV/μm (LET45-LET55), and higher spinal cord D_mean(P=0.03－0.00). The follow-up rate was 97.4%. After radiotherapy, the 1-, 3-, and 5-year OS rates were 65.5%, 26.1%, and 18.5%, respectively, and the median survival time was 20 months. There were no significant differences in OS rate and the incidence of acute radiation pneumonitis and radiation esophagitis between patients treated with IMRT and 3DCRT (P=0.06,0.73,0.13). Stratified analysis showed that, when comparing the patients treated with IMRT with those treated with 3DCRT, the survival rate was only lower in male patients, patients in stage T₃-T₄ or N₀-N₂, and those without chemotherapy (P=0.04,0.04,0.02,0.00). Conclusions The treatment outcomes of patients with stage Ⅲ NSCLC undergoing IMRT and 3DCRT are comparable. IMRT shows a potential dosimetric advantage, but the result needs further investigation.
		2015 Vol. 24 (2): 126-130 [Abstract] ( 2746 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	131	Primary clinical study of hippocampal-sparing prophylactic cranial irradiation in limited-stage small-cell lung cancer
		Dong Xin, Zhou Zongmei, Miao Junjie, Chen Xinyuan, Hu Zhihui, Huang Peng, Zhang Yin
		Objective To preliminarily observe the clinical efficacy of hippocampal-sparing prophylactic cranial irradiation (HS-PCI) using helical tomotherapy (HT) in patients with limited-stage small-cell lung cancer (LS-SCLC) after chemoradiotherapy, and compare HT with intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) in dose distribution. Methods From April to June, 2014, six patients with LS-SCLC who had achieved a complete remission after chemoradiotherapy were assigned to HS-PCI using HT within a month after brain metastasis was ruled out using brain magnetic resonance imaging (MRI). After fusing CT images and MRI images, the hippocampus was contoured in the fusion images and hippocampal avoidance regions were created using a volumetric expansion of 3 mm around the hippocampus. A dose of 25 Gy in 10 fractions to 95% of planning target volume (PTV) was prescribed in HT, IMRT, and VMAT. The clinical efficacy, adverse reactions, neurocognitive function, and brain metastasis were evaluated for HT. The dose distribution in PTV and hippocampus were compared between HT, IMRT, and VMAT. Results There were one patient with abdominal wall and abdominal lymph node metastases, one patient with local recurrence, and no patient with brain metastasis during the observation period. The numbers of patients with grade 1 and grade 2 headache, dizziness, and hair loss reactions were 3 and 1, 3 and 1, and 4 and 2, respectively. There were no significant differences in the average score of the Mini-Mental State Examination before treatment and at 3 and 6 months after treatment (29.7, 29.2, and 29.3;P=0.083, 0.317, and 0.157). The mean dose to the hippocampus was 16.85 Gy for IMRT and 17.59 Gy for VMAT. For HT, the mean doses to the hippocampus and avoidance regions were reduced to 5.26 Gy and 6.21 Gy, respectively. The prescribed dose for HT was reduced by 79% and 71% compared with IMRT and VMAT, respectively. The average coverage rate of the prescribed dose was 94.48% for HT. Conclusions HT achieves promising dose distribution and target coverage in sparing of the hippocampus. Moreover, HT dose not increase the incidence of adverse reactions. The change in neurocognitive function needs to be further studied with long-term observation and large-scale sampling.
		2015 Vol. 24 (2): 131-135 [Abstract] ( 2974 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	136


		2015 Vol. 24 (2): 136-137 [Abstract] ( 1867 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	138	Clinical value of radiotherapy in early DLBCL patients with complete remission after chemotherapy
		Liu Jianjiang,Zhang Na,Liu Luying,Liu Peng,Luo Jialin,Lu Ke,Zhou Ning,Tang Zhongzhu,Zhu Yuan
		Objective To investigate the value of radiotherapy (RT) in patients with early diffuse large B-cell lymphoma (DLBCL) who have achieved a complete remission (CR) after chemotherapy. Methods A retrospective analysis was performed on 376 patients with stage Ⅰ and Ⅱ DLBCL who were admitted to our hospital from 2004 to 2012. All patients achieved a CR after receiving chemotherapy with cyclophosphamide, doxorubicin/epirubicin, vincristine and prednisone (CHOP) or rituximab combined with CHOP (R-CHOP) for at least three cycles. The median age was 53 years. Patients were divided into four groups:R-CHOP group (n=92), R-CHOP+RT group (n=79), CHOP group (n=107), and CHOP+RT group (n= 98). The RT used was involved-field irradiation and the total dose ranged from 30 to 56 Gy. The survival rate was determined using the Kaplan-Meier method, and the survival difference analysis was performed using the log-rank test. Multivariate prognostic analysis was performed using the Cox proportional hazard model. Results The 5-year sample size was 188. The 5-year disease-free survival (DFS) and overall survival (OS) rates in all patients were 80.7% and 87.6%, respectively. The 5-year DFS and OS rates in the R-CHOP+RT group were significantly higher than those in the R-CHOP group (94.9% vs. 88.1%, P=0.030;97.9% vs. 86.0%, P=0.026). No significant differences in DFS and OS rates were observed between the CHOP+RT and CHOP groups (74.2% vs. 71.4%, P=0.623;74.2% vs. 71.4%, P=0.623). Multivariate prognostic analysis revealed that the smoking index<500, international prognostic index<2, and use of rituximab were favorable prognostic factors (P=0.034－0.000). Conclusions Radiotherapy can improve the DFS and OS in early DLBCL patients with CR after R-CHOP chemotherapy. All early stage DLBCL patients are recommended to undergo rituximab-containing chemotherapy followed by radiotherapy. Randomized controlled trials are needed to validate the results.
		2015 Vol. 24 (2): 138-142 [Abstract] ( 3366 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	143	Efficacy and safety of preoperative neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer:a clinical analysis of 291 patients
		Huang Rong,Zhang Luning,Xiao Weiwei,Chen Li,Zeng Zhifan,Ding Peirong,Gao Yuanhong,Chen Gong,Pan Zhizhong,Liu Mengzhong,Wan Desen
		Objective To evaluate the efficacy and safety of neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer (LARC) before surgery. Methods A total of 291 LARC patients who received preoperative chemoradiotherapy and surgery with or without postoperative adjuvant chemotherapy from March 2003 to May 2012 were included in the study. The radiotherapy delivered was two-dimensional conformal radiotherapy (2DRT) and three-dimensional conformal radiotherapy (3DRT), and the total dose ranged from 45 to 50 Gy in 23－25 fractions. All the patients received preoperative chemotherapy including FOLFOX6, XELOX, and Xeloda for 2－4 cycles. Surgery following the principle of total mesorectal excision was performed 3－8 weeks after radiotherapy. Postoperative adjuvant chemotherapy was delivered to 134 patients. The overall survival (OS), disease-free survival (DFS),relapse-free survival (RFS), and distant metastasis-free survival (DMFS) were determined using the Kaplan-Meier method, and survival difference analysis and univariate prognostic analysis were performed using the log-rank test. Multivariate prognostic analysis was performed using the Cox proportional hazard model. Results All the patients completed the preoperative neoadjuvant chemoradiotherapy and surgery. The rate of radical resection (R0) was 98.9%, and the sphincter preservation rate was 53.6%. The downstaging rates in tumor (T) stage, node (N) stage, and clinical stage were 73.1%, 83.6%, and 79.4%, respectively. Pathologic complete response rate was 26.8%. Grade 3 adverse hematologic reactions, grade 3 diarrhea, and grade 3 radiodermatitis were observed in 7.9%, 7.2% and 2.7% of total patients, respectively. Postoperative perineal pain and delayed wound healing were reported in 12.3% and 8.2% of total patients, respectively. The follow-up rate was 94.5% and the 5-year sample size was 95 patients. The 5-year OS, DFS, RFS, and DMFS were 76.6%, 72.1%, 88.8%, and 79.7%, respectively. The 5-year local recurrence rate and distant metastasis rate were 7.5% and 15.8%, respectively. Multivariate analysis revealed that the postoperative pathological staging was a prognostic influencing factor. Conclusions Preoperative neoadjuvant chemoradiotherapy increases the R0 and sphincter preservation rates, and results in significant tumor downstaging. Treatment-related adverse reactions are moderate and perioperative complications are not increased. The local recurrence rate is low and long-term survival rate is increased. Clinical application of preoperative neoadjuvant chemoradiotherapy as a standard treatment regimen for LARC is highly recommended.
		2015 Vol. 24 (2): 143-148 [Abstract] ( 2677 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	149	Risk factors for supraclavicular nodal failure in breast cancer patients with one to three positive axillary nodes treated with breast conserving surgery
		Li Shuai, Wang Shulian, Li Yexiong, Song Yongwen, Wang Weihu, Jin Jing, Liu Yueping, Fang Hui, Ren Hua, Liu Xinfan, Yu Zihao
		Objective To evaluate the supraclavicular nodal failure (SCF) of the breast cancer patients with one to three positive axillary nodes treated with breast conserving surgery and to identify the risk factors for SCF. Methods From Jan. 2001 to Mar. 2014, 256 breast cancer patients with one to three positive axillary nodes treated with breast conserving surgery and axillary dissection were analyzed. All patients received whole breast radiation to a total dose of 46－50 Gy (median 50 Gy) at 2 Gy/f or 43.5 Gy at 2.9 Gy/f. Tumor bed was boosted to 50－70 Gy (median 60 Gy) at 2 Gy/f or 52.2 Gy at 2.9 Gy/f. No patient received regional nodal radiation. 245(95.7%) patients received adjuvant chemotherapy. The SCF, LRR, DM and OS rates were calculated by Kaplan-Meier method and compare by the Logrank test. Results The number of samples were 101 followed up at 5 years. The 5-year SCF, LRR, DM and OS rates were 2.1%, 2.1%, 5%, 98%, respectively. LVI and 2 to 3 positive axillary node and Luminal B were risk factors for SCF (P=0.030,0.010,0.006). The 5-year SCF rate were 5.3% for patients with 2－3 positive axillary nodes and 2.8% for those with 1 positive nodes (P=0.010);5.3% and 1.8% for those LVI positive and negative (P=0.030);7.1%, 3.2%, 1.2% and 0% for Luminal B, Basal, Luminal A and Her-2 positive type (P=0.006). Patients with 0, 1 and2-3 risk factors had 5 year SCF rates of 0%, 3.0% and 10.6%(P=0.000). Conclusions The supraclavicular nodal recurrence rate is very low for breast cancer patients with one to three positive axillary nodes treated with breast conserving surgery without supraclavicular nodal radiation, indicating that prophylactive supraclavicular nodal is not necessary. Further research is needed to verify whether those patients with risk factors need SCF radiation or not.
		2015 Vol. 24 (2): 149-153 [Abstract] ( 2476 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	154	Standard whole breast tangential fields provide suboptimal axillary coverage and whole axilla radiation significantly increase lung dose in Chinese breast cancer patients treated with breast conservative surgery and sentinel node biopsy
		Peng Ran, Wang Shulian, Ren Wenting, Wang Weihu, Fang Hui, Song Yongwen, Liu yueping, Zhang Ke, Miao Junjie, Li yexiong
		Objective This study aimed to evaluate the coverage of the Level I and Ⅱ axilla with standard whole breast tangential fields (WBTF), and to what extent that whole axilla radiation could increase the dose to normal tissue with dosimetric study. Methods Fifteen consecutive left breast cancer patients treated with breast conservative surgery and sentinel node biopsy followed by whole breast radiation were studied. All had inverse IMRT plan using WBTF with prescription dose of 50 Gy to 95% of the planning target volume (PTV), defined as the whole breast. Level I and Ⅱ axilla was contoured according to the RTOG atlas. The dose distribution and coverage of Level I and Ⅱ axilla with WBTF was calculated. New plans delivering 50 Gy to 95% of the whole breast as well as Level I and Ⅱ axilla (WB+AX) were designed. The homogeneity index (HI=D₅/D₉₅) of the whole breast and conformal index (CI=VRI/TV, TV=target volume, VRI=Volume of the Reference Isodose) of the two plan, the dose to the heart, lung, left anterior descending coronary artery (LAD) and contralateral breast were compared between WBTF and WB+AX. Results The volume of Levels I and Ⅱ axilla was 71.7 and 26.5 cm², respectively. With WBTF, the average dose to Levels I and Ⅱ axilla was 34.39 Gy and 21.90 Gy, respectively. The V₅₀ and V₄₀ were 22.57% and 49.86% for Level I axilla, 5.99% and 21.99% for Level Ⅱ axilla. WB+AX significantly increased the HI of the whole breast, and CI of the two plans and also significantly increased the dose to the ipsilateral lung and heart as compared with WBTF. There was no significant difference in mean dose to LAD between WBTF and WB+AX. Conclusions Standard whole breast tangential field doesn′t offer optimal coverage of Level I and Ⅱ axilla. Patients who had high-risk relapse of axilla should be planned to adequately cover the whole axilla if axilla dissection is not performed. Given the compromised dose homogeneity of the whole breast and the significantly increased lung dose with WB+AX plan, axilla dissection and axilla radiation should be weighted and discussed with patients for those who need axilla treatment.
		2015 Vol. 24 (2): 154-158 [Abstract] ( 2801 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	159	Effect of bladder volume change on normal tissue doses in external 3DRT and 3D conformal brachytherapy for cervical cancer
		Shi Dan, Zhao Zhipeng, He Mingyuan, Zhao Hongfu, Cheng Guanghui
		Objective To evaluate the effect of bladder volume change on the doses to normal tissues in cervical cancer patients undergoing external three-dimensional conformal radiotherapy (3DRT) plus 3D conformal brachytherapy (3DCBT). Methods The study included 56 patients with cervical cancer who were admitted to our hospital from 2012 to 2013 and received radical external 3DRT and 3DCBT. During 3DCBT, the doses to 0.1, 1.0, and 2.0 cm³(D₀.1 cm³, D₁.0 cm³, and D₂.0 cm³, respectively) for the rectum, small intestine, sigmoid colon, and bladder under different bladder filling status (empty, 50, 100, and 150 ml) were compared and analyzed by paired t-test. Results The rectum D₀.1 cm³ with bladder volumes of 50 and 100 ml were significantly reduced compared with that with an empty bladder (P=0.000,0.000). The D₀.1 cm³, D₁.0 cm³, and D₂.0 cm³ for the small intestine with bladder volumes of 50, 100, and 150 ml were significantly reduced compared with those with an empty bladder (P=0.008,0.000,0.000 and 0.000,0.000,0.000 or 0.000,0.000,0.000). The D₀.1 cm³, D₁.0 cm³, and D₂.0 cm³ for the bladder with bladder volumes of 100 and 150 ml were significantly increased compared with those with an empty bladder (P=0.000,0.000 and 0.000,0.000 or 0.000,0.000). Conclusions The doses to the bladder and small intestine are influenced by different bladder filling status, but the doses to the rectum and sigmoid colon show no significant variation. The increase in bladder volume is helpful in reducing the dose to the small intestine. Without any change in the bladder dose, the bladder volume of 50 ml is more beneficial to reduce the dose to the small intestine than those of 100 and 150 ml.
		2015 Vol. 24 (2): 159-162 [Abstract] ( 2644 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	163	Four-dimensional CT-based evaluation of intrafractional and interfractional anastomosis motion during postoperative radiotherapy in gastric cancer:a prospective study
		Liu Wenyang, Jin Jing,Tian Yuan,Han Wei, Ren Hua, Fang Hui, Li Yexiong, Wang Shulian, Wang Weihu, Song Yongwen, Liu Yueping, Liu Xinfan, Yu Zihao
		Objective To study the intrafractional and interfractional anastomosis motion during postoperative adjuvant radiotherapy in gastric cancer by four-dimensional CT (4DCT). Methods Eight patients with locally advanced gastric cancer who underwent Billroth I gastrectomy and postoperative radiotherapy were enrolled in this study and prospective analysis was performed. A total of four 4DCT, preoperative and intraoperative, were performed during free breathing and dietary restriction. The implanted anastomotic nail was used as the observational subject, and the intrafractional and interfractional anastomosis motion was evaluated in the right-left (RL), anterior-posterior (AP), and superior-inferior (SI) directions. The relationship between the volume change in remnant stomach and interfractional anastomosis motion was analyzed. The differences within and between groups were analyzed by paired t test and one-way ANOVA, respectively. Results The intrafractional anastomosis motion was 2.4±2.3 mm, 2.1±2.0 mm, and 5.6±4.0 mm in RL, AP, and SI directions, respectively, and the motion in SI direction was significantly greater than that in RL and AP directions (P=0.000 and 0.000). The interfractional anastomosis motion was 6.1±6.6 mm, 3.3±3.0 mm, and 4.8±4.3 mm in RL, AP, and SI directions, respectively, with no significant differences between different directions (P=0.064,0.156,0.161). In RL direction, the interfractional anastomosis motion was significantly greater than the intrafractional anastomosis motion (P=0.018). The internal margins accounting for respiration related displacement and interfractional variability were 24.2 mm, 10.3 mm, and 18.3 mm in RL, AP and SI directions, respectively. Conclusions The intrafractional and interfractional anastomosis motion should be considered during postoperative adjuvant radiotherapy in gastric cancer patients who have undergone Billroth I gastrectomy. The internal margins required for anastomosis in RL, AP and SI directions are 24.2 mm, 10.3 mm and 18.3 mm, respectively.
		2015 Vol. 24 (2): 163-167 [Abstract] ( 3173 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	168	Evaluation of long-term efficacy of re-irradiation with intensity-modulated radiotherapy for locally recurrent nasopharyngeal carcinoma
		Tian Yunming, Bai Li, Xiao Weiwei, Zeng Lei, Liu Shuai, Huang Shaomin, Deng Xiaowu, Lu Taixiang, Zhao Chong, Han Fei
		Objective To retrospectively analyze the long-term survival, late adverse events, and prognostic factors in patients with locally recurrent nasopharyngeal carcinoma (NPC) after re-irradiation with intensity-modulated radiotherapy (IMRT). Methods From 2001 to 2010, a total of 335 patients who were diagnosed with locally recurrent NPC and received re-irradiation with IMRT were included in the study. Among all the patients, 69(20.6%) had radiotherapy complications. There were 268 male patients (80.0%) and the median age was 45.0 years (range:21－75 years). The numbers of patients in disease stages T₁, T₂, T₃, and T₄ were 41, 36, 122, and 136, respectively. The median tumor volume was 37.5 cm³, and the median prescribed dose to the target volume was 68 Gy (range:60－70 Gy). The survival rate was determined using the Kaplan-Meier method. Prognostic factors were analyzed by the Cox proportional hazard model. Results The 5-year follow-up sample size was 290 patients. The 5-year overall survival, local-regional failure-free survival, and distant failure-free survival were 34.7%,64.2%, and 82.2%, respectively. Multivariate analysis indicated that the poor prognostic factors included age>45 years (P=0.01), presence of significant radiotherapy complications before IMRT (P=0.00), tumor stages (T₂-T₄)(P=0.00), tumor volume>38 cm³(P=0.01), and the mean dose of gross tumor volume (GTV_nx)>68 Gy (P=0.01). The incidence rates of nasopharyngeal mucosa necrosis, epistaxis, radiation encephalopathy, cranial nerve injury, and trismus were 28.6%, 16.4%, 22.4%, 15.8%, and 13.7%, respectively. Conclusions Re-irradiation with IMRT is effective in controlling tumor and thus is a reasonable choice for patients with locally recurrent NPC. However, the incidence of severe adverse events is still high. Further investigation on how to maintain the balance between tumor control and normal organ protection is needed.
		2015 Vol. 24 (2): 168-173 [Abstract] ( 2636 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	173	Efficacy of tailor-made mouth bite block in reducing setup errors during radiotherapy for nasopharyngeal carcinoma
		Zhang Tao, Xiao Guangli, Wu Zhaoping, Zhu Xiangshang, Wang Hanyang, Long Huijuan, Qiu Xibin, Cao Yabing
		Objective To evaluate the efficacy of tailor-made mouth bite block for auxiliarypositioning in reducing setup errors during radiotherapy for nasopharyngeal carcinoma (NPC). MethodsThe NPC patient to be treated with radiotherapy was immobilized with a thermoplastic mask covering the head, neck, and shoulder, with the addition of a tailor-made mouth bite block to help positioning. The patient′s position was verified by the On-Board Imager system for the first three times of radiotherapy and then once every week. Results The mean setup errors in left-right, superior-inferior, and anterior-posterior directions were －0.26, 0.36, and 0.35 mm, respectively, and the standard deviations were 0.97, 1.16, and 1.11 mm, respectively;the frequencies of setup error ≤2 mm in the three directions were 99.7%, 98.0%, and 100%, respectively. Conclusion Tailor-made mouth bite block can help improve the positioning accuracy during radiotherapy for NPC.
		2015 Vol. 24 (2): 173-175 [Abstract] ( 3651 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	176	Aapplied analysis of radiotherapy apparatus schedule optimization for tumor patients
		Fu Guishan, Huang Peng,Ma Pan, Zhang Ke, Zhang Zhong,Dai Jianrong
		Objective To design and develop a treatment unit selecting system in aim of enhancingwork efficiency and safety, adjusting treatment unit workload,improving quality of medical care. MethodsVarious treatment techniques, immobilization devices and setup verification devices were modeled in software. Workload of treatment units were extract from the Record and Verify System. These two types of information were then combined with the unit′s workload capability to calculate the optimal radiotherapy apparatus for tumor patient. Results The system had finished selecting radiotherapy apparatusv for more than 5000 patients since its taking place of the old patient selecting methods. Maximum variation of daily treatment duration between treatment units had decreased from 4-5 hours (mean 4.22 hours) to 1-2 hours (mean 1.84 hours) since the system have been put into operation. Workload and device configuration of various units could be controlled by easily editing of the system configuration file. Conclusions The system developed not only accomplish patient selecting in an optimal and safe way, but also provide a way of easily control the treatment unit workload.
		2015 Vol. 24 (2): 176-179 [Abstract] ( 2989 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	180	Use of maximum heart distance to evaluate heart dosimetry for tangential field radiotherapy in left-sided breast cancer after modified radical mastectomy
		Wang Shengye, Du Xianghui, Bai Xue, Su Feng, Wang Yuezhen, Chen Jianxiang, Shi Guodong, Zheng Yuanda,Wang Jin, Chen Ming
		Objective To assess the value of maximum heart distance (MHD) in predicting the dose of tangential field heart irradiation in left-sided breast cancer. Methods A total of 40 left-sided breast cancer patients who were given adjuvant tangential field irradiation on the left chest wall after modified radical mastectomy in our hospital from January 2010 to December 2011 were selected in this study. For each patient, the following parameters were derived using three-dimensional treatment planning system:MHD, mean dose (D_mean) to organs at risk including the whole heart, left anterior descending (LAD) coronary artery, left ventricle (LV), and anterior myocardial territory (AMT), thickness of the contralateral breast tissue, and thickness from the sternum to the body surface (measuring body fat). The relationship between MHD and each D_mean was analyzed by curve fitting equation. The reliability of R2>0.8 represented a good correlation. Results The MHD of 40 patients was between 1.14 and 5.34 cm (2.66±0.16 cm). The R2 values of first-, second-, and third-order curve fitting equations were 0.869, 0.875, and 0.883, respectively, between MHD and whole heart D_mean(all P=0.000);0.777, 0.799, and 0.8133, respectively, between MDH and AMT D_mean(all P=0.000);0.598, 0.601, and 0.6333, respectively, between MHD and LV D_mean(all P=0.000);and 0.418, 0.470, and 0.4723, respectively, between MHD and D_mean of the LAD coronary artery (all P=0.000). The D_mean of all the heart compartments was not affected by the body fat thickness. Conclusions MHD is a reliable predictor of the mean dose to organs at risk (whole heart and AMT) in tangential field radiotherapy for left-sided breast cancer.
		2015 Vol. 24 (2): 180-183 [Abstract] ( 2762 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	184	The accuracy of image registration methods for image-guided positioning in lung cancer radiotherapy
		Peng Yinglin, Liu Songran, Huang Botian, Lin Maosheng, Zhang Dandan, Hu Jiang, Liu Hui, Luo Guangwen. Deng Xiaowu, Bao Yong
		Objective To study the accuracy of different methods of CBCT image registration used in image-guided radiotherapy, and provide reasonable guidance for clinic application. Methods Planning CT and CBCT images acquired in first fraction of 15 lung cancer cases were studied, registered with different match method (bony/gray registration) and different match region (target only/ipsilateral structure/body).The CBCT target volume (GTVCBCT) coverage by planning target volume (PTV_CT), the dice similarity coefficient (DSC) between the GTV_CT and GTVCBCT and between the OARCT and OARCBCT, and the position deviation of the GTV geometric center were compared. Results The bony registration had worse precision, especially in the target only. The coverage ratio of PTV_CT to GTVCBCT of bony and gray registration in the target only, ipsilateral structure, body group were (66±35)% and (97±8)%(P=0.005),(98±5)% and (99±2)%(P=0.034),(98±4)% and (98±4)%(P=0.478), respectively. Using gray registration to register the ipsilateral structure had the best results, with the DSC of GTV and OARs of 0.86±0.10(GTV), 0.71±0.10(esophagus), 0.76±0.10(spinalcord), 0.89±0.05(heart), and the deviation of GTV center of (0.25±0.16) cm. Conclusions Clinical positioning accuracy is achievable using CBCT guidance in lung cancer radiotherapy, and registering ipsilateral structure or body is recommend since small area registration is lack of accuracy.
		2015 Vol. 24 (2): 184-188 [Abstract] ( 2815 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	189	Analysis on the dose characteristics of Body γ Knife and Tomotherapy treatment for hepatocellular carcinoma
		Zhu Fuhai, Wu Weizhang, Ren Gang, Wang Yong, Wang Yingjie, Xia Tingyi
		Objective To study the dose characteristics of Body γ Knife and Tomotherapy treatment plans for hepatocellular carcinoma, and compare their differences between organs at risk (OAR) dose and the range of low dose. Methods CT simulation images of twelve patients with hepatocellular carcinoma were selected, the target volume and OAR were drew by doctor. Body γ Knife and Tomotherapy treatment plans were optimized with their own planning station. The dosimetric characteristics were evaluated by dose volume histograms and were compared. To analyze the difference between the two techniques, the paired t-test was applied. Results The D_max and D_mean of target with Body γ Knife were higher than Tomotherapy (P=0.002,0.000), but the conformal index of PTV of Tomotherapy was superior to the Body γ Knife (P=0.001). The D_max of spinal cord and left kidney with Body γ Knife was lower than Tomotherapy (P=0.013,0.012), and it was also in the D_mean of stomach and left kidney (P=0.010,0.023). In the volume dose comparison, the V₄₀, V₃₅, V₃₀, V₂₅ and V₂₀ of normal tissue (all Body-PTV) and liver (all liver-GTV) with Body γ Knife were higher than Tomotherapy (P=0.001,0.001,0.001,0.007,0.029), but the V₁₀ and V₅ were lower (P=0.019,0.031), the D_max of stomach, D_mean of right kidney and liver were no statistical difference (P=0.247,0.308,0.401). Conclusions Both treatment plans could meet the clinical dosimetric need, by the same prescription dose, D_max and D_mean of target of Body γ Knife were higher than Tomotherapy. Tomotherapy had excellent dose-target conformal and could reduce the range of V₂₅-V40 of OAR and normal tissue, but the range of V₅-V10 was increased obviously.
		2015 Vol. 24 (2): 189-192 [Abstract] ( 2632 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	193	The application of ExacTrac X-ray image guide system for the therapy of head tumor and quality control
		Ying Wei,He Youan,He Yong, Zhang Dekang
		Objective To study the ExacTrac X-ray image guide system for patients with head and neck cancer. Methods Ten patients were chosen foe this study. It was immoblized using the head mask and frame fixtures. The two KV X-ray units were matched with the digitally reconstructed radiographs after positioning with the infrared markers.Then the setup errors on x (horizontal axis),y (vertical axis) and z (up-down) directions and rotation errors were obtained.Paired t-test between any two direction difference errors. Results The setup errors with ExacTrac X-ray image guide system for the patients in x,y,z directions and rotation errors were (0.57±0.24) mm,(0.68±0.19) mm,(1.54±0.29) mm,(0.54±0.13)°,(0.60±0.23)°,(0.51±0.15)°.The z-axis direction have slightly larger error (P=0.02,0.01).The others have not statistical significance (P=0.06,0.10－0.41). Conclusions To use ExacTrac X-ray image guide system cooperating with the six degree of freedom treatment couch in image guided radiotherapy for is feasible, the motion errors<2 mm,the rotation errors<2°.Reduced of the setup errors with replace the sphere or to reduce pollution of the sphere, improve the accuracy,it could provide a better quality assurance in radiation therapy.
		2015 Vol. 24 (2): 193-195 [Abstract] ( 2537 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	196	The research of accuracy immobilized using individualized polyurethane scaling agent compared to positioning foam with standard plastics pillow in the radiotherapy of nasopharyngeal carcinoma
		Xu Senkui, Yao Wenyan, Hu Jiang, He Huilang, Zhang Huaman, Chen Cui, Zhang Guangshun, Lin Chengguang
		Objective To study the superiority of polyurethane foam sealing agent immobilization with KV-CBCT for the patients with nasopharyngeal carcinoma (NPC). Methods 36 NPC patients were divided into two groups. Group A was immobilized using standard plastics pillow with the head-and-neck thermoplastic masks, and so do individualized polyurethane foam sealing agent pillow as group B. CBCT was weekly carried out weekly, and the setup errors of the head and neck position (axial (x, y, z)) were analyzed by paired t-test. The marginal was caculated using 2.5Σ+0.7σ. Results On x-, y-, z-axial,the average setup errors values of head and neck position were (－0.27±1.33) mm,(－0.31±1.50) mm,(0.54±0.90) mm and (－0.59±2.76) mm,(－0.11±2.23) mm,(0.66±1.60) mm;and the marginal were 3.28 mm, 3.64 mm,1.86 mm and 6.17 mm, 5.17 mm, 3.52 mm,respectively in Group A;with (－0.44±0.87) mm、(－0.18±1.06) mm、(0.13±0.72) mm and (－0.07±1.58) mm,(－0.04±2.11) mm,(0.03±1.31) mm, and 2.07 mm, 2.46 mm,1.71 mm and 3.57 mm, 5.03 mm, 3.16 mm, respectively in Group B.Compared with Group A to Group B,P value were 0.315,0.011,0.000 and 0.045,0.630,0.002 On x-, y-, z-axial. Conclusions The application of polyurethane foam sealing agent in the immobilization of NPC patients is better than standard plasthetics pillow, and especially for the positioning of neck. Compared to head position, the setup errors of neck are larger, so it is suggested to make the outer margin separately.
		2015 Vol. 24 (2): 196-199 [Abstract] ( 2783 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	200	Quality control of linac in daily volumetric-modulated arc therapy
		Li Guangjun, Li Yanlong, Xiao Jianghong, Wang Xuetao, Su Chen, Bai Sen
		Objective To verify the daily delivery accuracy of volumetric-modulated arc therapy (VMAT) and achieve the process quality control (PQC) of linac using statistical process control (SPC) technology. Methods The log files of all treatments were taken out from the linac system. An in-house software which created by Matlab 7.14 was used to analyze the daily parameters accuracy and the mechanism and dose delivery accuracy of the linac for each VMAT, and an daily evaluation report was automatically created for the linac. The stability of the linac and the deviation of the delivery accuracy for various cancer sites were also analyzed. To achieve the process quality control of linac using SPC technology, the control limit of each parameter was calculated by Johnson alternation and the single value control charts were drawn. Results 76 patients mainly with nasopharyngeal carcinoma, cervical carcinoma, rectal cancer and laryngeal cancer, got the treatment daily with VMAT technology, and a total of 2446 arcs were delivered by the linac in continuous 16 days. The gantry angle error, y and x collimator position error, MLC leaf position error and dose delivery error were 0.49°, 0.09 mm, 0.38 mm, 0.31 mm, 0.05 MU, respectively. Compare to the nasopharynx, uteri, rectal and larynx cancer, it can be seen that the variation factors of dose delivery and gantry angle errors for various cancer sites were higher, which was 8.10% and 4.54%, respectively. Through the process quality control of the linac, it was found that all the parameters were in control. While some abnormal points arose (the error was greater than UCL), and the ratio of the gantry angle which was out of control (0.45%) was the highest in all parameters. Conclusions linac delivery accuracy could be monitored and verified during the whole VMAT treatment for each patient, and the daily running condition of linac could be monitored. Through the introduction of SPC technology and the control charts, the process quality control of linac in VMAT could be achieved. It is a financial and valid method for the daily quality assurance of linac.
		2015 Vol. 24 (2): 200-103 [Abstract] ( 2636 ) [HTML 1KB] [ PDF 0KB] ( 0 )

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		2015 Vol. 24 (2): 204-108 [Abstract] ( 2160 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	209	A study of deformable image registration of high-dose-rate brachytherapy CT image to intensity modulated radiation therapy CT image
		Zhen Xin, Chen Haibin, Xiao Yang, Hu Jie, Zhou Linghong
		Objective To study a novel method for the high-dose-rate brachytherapy (HDR) CT image to the intensity modulated radiation therapy (IMRT) CT image deformable image registration and dose accumulation. Methods The applicator in the HDR CT image is first segmented and removed, then a deflation step is performed on the applicator-free HDR CT image by solving the Navier-Stokes equation. Demons algorithm is utilized to register the deflated HDR CT image to the IMRT CT image, along with the HDR dose. The deformed HDR dose is then added on the IMRT dose and yield the final accumulated dose. Results The HDR CT image and IMRT CT image, as well as the corresponding dose distribution, from the cervical cancer patients are used for evaluation of the proposed algorithm, the results show that the proposed method can effectively get rid of the influence of the applicator and produce an accurate accumulated dose. Conclusions Dose accumulation and supervision is an important step in adaptive radiotherapy for accurate dose delivery and treatment plan re-optimization. The proposed method in this study can effectively accumulate the HDR dose to the IMRT dose domain, and the accuracy is proved to be sufficient for clinical needs.
		2015 Vol. 24 (2): 209-211 [Abstract] ( 2579 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	212


		2015 Vol. 24 (2): 212-213 [Abstract] ( 1751 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	214	Effect of silencing Annexin A2 gene expression by siRNA on radiosensitivity of nasopharyngeal carcinoma cells
		Su Ying, He Huocong, Wu Junxin, Zou Changyan, Lin Keyu, Chen Chao
		Objective To investigate the effect of silencing Annexin A2 gene expression by small interfering RNA (siRNA) on the radiosensitivity of nasopharyngeal carcinoma cells CNE-2(R743). Methods siRNA targeting the Annexin A2 gene was chemically synthesized and transfected into R743 cells by HiPerFect. The mRNA and protein levels of Annexin A2 before and after transfection were measured by RT-PCR and Western blot, respectively. The change in radiosensitivity of R743 cells was analyzed by colony-forming assay. Cell cycle distribution and apoptosis after X-ray irradiation were analyzed using flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling assay, respectively. Results The results from RT-PCR and Western blot showed that the expression of Annexin A2 was down-regulated after transfection. The colony-forming assay indicated that the D₀, D_q, and SF₂ in transfected cells were significantly lower than those in untransfected cells with radiation alone and in cells transfected with control siRNA. The sensitization enhancement ratios (D₀ ratios) of transfected cells relative to untransfected and control siRNA transfected cells were 1.30 and 1.27, respectively. After X-ray irradiation,the proportion of cells in G₂/M phase was significantly higher in the transfected cells than in untransfected and control siRNA transfected cells (32.46% vs 9.17% and 9.42%, respectively;P=0.000 and 0.000). The apoptosis rate was also significantly higher in the transfected cells than in the untransfected and control siRNA transfected cells (35.20% vs 10.87% and 11.33%, respectively;P=0.000 and 0.000). Conclusions Silencing Annexin A2 gene expression by siRNA can increase the radiosensitivity of R743 cells, which may be associated with DNA damage repair and change in cell cycle distribution.
		2015 Vol. 24 (2): 214-217 [Abstract] ( 2581 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	218


		2015 Vol. 24 (2): 218-221 [Abstract] ( 2796 ) [HTML 1KB] [ PDF 0KB] ( 0 )

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		2015 Vol. 24 (2): 222-225 [Abstract] ( 2150 ) [HTML 1KB] [ PDF 0KB] ( 0 )

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		2015 Vol. 24 (2): 226-230 [Abstract] ( 1716 ) [HTML 1KB] [ PDF 0KB] ( 0 )

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Cancer Hospital of Chinese
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