Objective To compare the long-term efficacy between intensity-modulated radiotherapy (IMRT) alone and concurrent chemoradiotherapy (CCRT) in the treatment of stage Ⅱ nasopharyngeal carcinoma (NPC) patients. Methods The clinical data of 123 patients with stage Ⅱ NPC were retrospectively analyzed. Eighty-one patients received IMRT alone,and 42 patients received CCRT.The Kaplan-Meier method was used to calculate survival rates,and the log-rank test was used to compare the survival rates. Results The 5-year overall survival (OS),local recurrence-free survival (LRFS),distant metastasis-free survival (DMFS),and progression-free survival (PFS) rates in all patients were 96.7%,94.7%,93.1%,and 87.8%,respectively. There were no significant differences between the patients receiving IMRT alone and CCRT in 5-year OS (98.7% vs.92.9%,P=0.569),LRFS (94.8% vs. 94.5%,P=0.770),DMFS (94.5% vs. 90.2%,P=0.408),and PFS (90.6% vs. 82.2%,P=0.340).For patients with stage T₂N₁ NPC,the 5-year OS,LRFS,DMFS,and PFS also showed no significant differences between those receiving IMRT alone and CCRT (P=0.929,0.967,0.917,0.492).The incidence rates of neutropenia,leukopenia,and mucositis were significantly higher in patients receiving CCRT than in those receiving IMRT alone (P=0.000,0.000,0.012,0.010),while the incidence of late toxicities was similar between the two groups of patients (P=0.823,0.622,0.113). Conclusions For stage Ⅱ NPC patients treated with IMRT,the addition of concurrent chemotherapy fails to improve the prognosis,and increases the incidence of acute toxicities.

Objective To evaluate the impact of three to four cycles of neoadjuvant chemotherapy (NACT) on the survival of patients with N₂-N₃ nasopharyngeal carcinoma (NPC). Methods The clinical data of 915 patients with T_1-4N_2-3M₀ NPC from 2007 to 2010 were retrospectively analyzed. A total of 179 patients treated with 3-4 cycles of NACT (NACT≥3 group) were matched with 358 patients treated with 2 cycles of NACT (NACT=2 group) and 179 patients treated without NACT (NACT=0 group, concurrent chemoradiotherapy group) for age, N stage, pathological subtype, and NACT regimen. The Kaplan-Meier method was used to calculate overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS), and distant metastasis-free survival (DMFS) rates, the log-rank test was used for survival difference analysis and univariate prognostic analysis, and the Cox proportional hazards model was used for multivariate prognostic analysis. Results For the NACT≥3, NACT=2, and NACT=0 groups, the 5-year OS rates were 89.4%, 81.6%, and 73.7%, respectively (P=0.000), the 5-year DFS rates were 83.2%, 69.8%, and 64.2%, respectively (P=0.000), the 5-year RFS rates were 86.0%, 76.0%, and 69.3%, respectively (P=0.001), and the 5-year DMFS rates were 86.6%, 76.0%, and 68.3%, respectively (P=0.000). Three to four cycles of NACT was an independent protective factor for OS, DFS, RFS, and DMFS in patients with N₂-N₃ NPC. Conclusion Three to four cycles of NACT can significantly improve the survival of patients with N₂-N₃ NPC.

Objective To investigate the failure mode in patients with stage pT₃N₀M₀ thoracic esophageal squamous cell carcinoma (TESCC) after surgery, and to discuss the significance and feasibility of postoperative radiotherapy according to the failure mode. Methods A retrospective analysis was performed on 227 patients with stage pT₃N₀M₀ TESCC who met the inclusion criteria from January 2007 to December 2010. Their postoperative failure mode was analyzed, and, with reference to relevant research, the significance of postoperative radiotherapy and its target patients were explored. The Kaplan-Meier method was used to calculate overall survival (OS), local recurrence (LR), and distant metastasis (DM) rates, and the log-rank test was used for survival difference analysis and univariate prognostic analysis. The Cox model was used for multivariate prognostic analysis. Results After surgery, there were 58 patients (25.6%) with LR in the thoracic cavity and 27 patients (11.9%) with DM, and 10 patients had both LR and DM. Twenty-nine (50%) of the 58 patients had recurrence in the thoracic mediastinal lymph nodes. The Results of univariate analysis showed that the 3-and 5-year OS rates of patients with upper thoracic esophageal cancer were significantly lower than those of patients with middle and lower esophageal cancer (P=0.000), and the chest-regional recurrence rate was significantly higher in the former group than in the latter two groups (P=0.047);the 3-and 5-year OS rates of patients with poorly differentiated squamous cell carcinoma were significantly lower than those of patients with moderately and well differentiated squamous cell carcinoma (P=0.005), and the DM rate was significantly higher than in the former group than in the latter two groups (P=0.000). The Results of multivariate analysis showed that lesion site and the degree of pathological differentiation were independent prognostic factors for OS (P=0.014 and 0.010);lesion site was the independent prognostic factor for chest-regional recurrence (P=0.046);the degree of pathological differentiation was the independent prognostic factor for DM (P=0.000). Conclusions For patients with stage pT₃N₀M₀ TESCC after two-field esophagectomy, the most common failure mode is chest-regional recurrence, especially in patients with upper thoracic esophageal cancer. Therefore, postoperative radiotherapy is suggested for upper-thoracic TESCC.

Objective To compare the dosimetry and toxicities between postoperative fixed-field intensity-modulated radiotherapy (FF-IMRT) and image-guided radiation therapy/volumetric modulated arc therapy (IGRT-VMAT) for cervical cancer. Methods A total of seventy patients with stage Ⅰ _b—Ⅱ _a postoperative cervical cancer who had high risk factors,were divided into FF-IMRT (FF-IMRT group,n=35) and IGRT-VMAT (IGRT-VMAT group,n=35),to compare the difference of target dose and adverse reaction between the two groups. Results In the IGRT-VMAT group,the interfractional setup errors in the x,y,and z axes were (0.25±0.14) cm,(0.26±0.16) cm,and (0.24±0.18) cm,respectively;the intrafractional setup errors in the x,y,and z axes were (0.1±0.09) cm,(0.12±0.09) cm,and (0.11±0.09) cm,respectively;the margins in the x,y,and z axes were 0.75 cm,0.84 cm,and 0.78 cm,respectively. Under the same dosimetric conditions,the IGRT-VMAT group was superior to the FF-IMRT group in terms of conformity index,treatment time,and number of monitor units (P=0.000). The D_mean and volume receiving high-dose irradiation for the bladder,rectum,and small intestine were significantly lower in the IGRT-VMAT group than in the FF-IMRT group (P=0.000). Compared with the FF-IMRT group,the IGRT-VMAT group had a significantly reduced incidence of acute and chronic gastrointestinal,urinary,and hematologic toxicities (P<0.05). Conclusions IGRT-VMAT can correct setup error online,shorten the treatment time,reduce the dose to organs at risk,and alleviate acute and chronic toxicities,and is especially suitable for patients with postoperative small bowel position changes.

Objective To investigate the dosimetric influence of dwell weight standard deviation (DWSD) and applicator displacement in cervical cancer patients treated with three-dimensional brachytherapy. Methods A total of 20 cervical cancer patients who had completed radical treatment were selected in this study. The Fletcher applicator (Nucletron#189.730) was used for these patients. A new plan, based on the former CT images and structures, was designed for each patient. In former and new plans, dwell weight was recorded, and DWSD was calculated. Two groups, low-DWSD (LDWSD, 0.141-0.299) and high-DWSD (HDWSD, 0.211-0.337), were set according to the DWSD size for the two plans. Dosimetric effects from ±1 mm displacement of tandem applicator or ovoid applicator were simulated with Oncentra^? Brachy V4.3 treatment planning system. D₁₀₀, D₉₀, and V₁₅₀ for clinical target volume (CTV) and D_0.1cc, D_1cc, and D_2cc for the bladder, rectum, and sigmoid were evaluated. Dosimetric comparisons were made between the LDWSD group and HDWSD group to study the dosimetric effects of DWSD and applicator displacement in cervical cancer patients. Results The dosimetric effects from applicator displacement increased with increasing DWSD. If there was a 1 mm displacement of tandem applicator or ovoid applicator, D₁₀₀, D₉₀, and V₁₅₀ of CTV were 3.0%, 23.8%, and 4.8% higher or 0.5%, 1.2%, and 5.2% higher in the HDWSD group than in the LDWSD group;D_0.1cc, D_1cc, and D_2cc of the bladder and rectum were significantly higher in the HDWSD group than in the LDWSD group, particularly for the sigmoid (up 44.0%, 22.8%, and 16.8%) and (up 10.3%, 14.4%, and 12.4%). Conclusions DWSD should be considered in plan evaluation for cervical cancer patients treated with three-dimensional brachytherapy. The dosimetric influence from applicator displacement can be decreased by reducing DWSD properly.

Objective To evaluate the dosimetric errors of organs-at-risk (OARs) induced by the optimal auto-segmentation using Mim Maestro based on dose calculation and measurement. Methods The Mim atlas library composed of 240 nasopharyngeal carcinoma, breast cancer, and rectal cancer patients that were retrospectively selected was used for the auto-segmentation of OARs on the CT images of corresponding regions in 76 patients. Relative to the manual contouring, one optimal case was selected from each site based on conformity index (CI), mean distance to conformity (MDC), relative volume difference (Dv%), DICE, sensitivity index (Se. Idx), and inclusion index (Inc. Idx). Treatment plans were made to satisfy the DVH constraints of OARs based on auto-contours, and then the dose errors to the actual organs were evaluated in terms of calculation and measurement. The paired t-test (normal distribution) or rank sum test (non-normal distribution). Results Significant differences were observed in the 76 patients between the manual and automated segmentation (P<0.05). For the optimal cases, the DICE index of various OARs ranged from 0.43 to 0.98,and 73%(16/22) of DICE values were higher than 0.70. The calculated dose errors to various OARs were (-1.15±15.94)%(95% CI:-8.21% to 5.92%)(mean dose) and (-6.53±21.13)%(95% CI:-15.90% to 2.84%)(maximum dose). The measured dose errors were (-2.43±24.52)%(95% CI:-13.30% to 8.44%)(mean dose) and (-3.38±20.87)%(95% CI:-12.63% to 5.87%)(maximum dose). Conclusion Without human interference, even the optimal auto-segmentation Results are not clinically acceptable for treatment planning.

Stage Ⅲ_A non-small cell lung cancer (NSCLC) has high heterogeneity and there are some controversies over the treatment of this disease, especially for patients with stage Ⅲ_A—N₂ NSCLC. This article investigates whether preoperative or postoperative radiotherapy can improve the survival of patients with stage Ⅲ_A—N₂ NSCLC and evaluates the effect of surgical treatment.