Objective To investigate the dosimetric characteristics between helical tomotherapy (HT) and intensity-modulated radiotherapy (IMRT) plans in children receiving craniospinal irradiation and estimate the risk of radiogenic second cancer according to the excess absolute risk (EAR) model. Methods Computer-tomography scans of 15 children who received craniospinal irradiation between 2012 and 2017 were selected. HT and IMRT plans were designed for each patient after contouring the volumes of tumors and organ at risks (OARs) and then the homogeneous index (HI), conformity index (CI), the maximum dose and the mean dose of OAR, V10 and V20 were analyzed to optimize the clinical treatment plan. The second cancer risk was estimated by DVH of each organ and EAR model and statistically compared between HT and IMRT. Results Both two plans met the clinical requirements in target coverage (100% dose≥95% target volume).The HI in the HT group was significantly superior to that in the IMRT group (P=0.000) whereas no significant difference was noted in CI between two groups. Compared with the IMRT plan, HT plan possessed absolute advantage in protecting hippocampus and the D2% and Dmean were significantly lower (P=0.000).As for the protection of OAR, the Dmax, Dmean and V20 of thyroid (P=0.001,0.002 and 0.014) and Dmax,V10 of heart (P=0.001 and 0.003) in the HT plan were significantly lower than those in the IMRT plan. In terms of second cancer risk, HT plan yielded a significantly higher second cancer risk for thyroid and lung compared with IMRT the EAR in thyroid was 28.666 vs. 26.926(P=0.010) and 20.496 vs. 18.922(P=0.003) in lung. Both plans yielded a relatively high second cancer risk for stomach (P=0.248), whereas a low second cancer risk for liver (P=0.020). Conclusions HT plan is superior to IMRT plan in the hippocampus-sparing craniospinal irradiation in children. However, HT plan yields a high second cancer risk for thyroid and lung. Consequently, the balance between the carcinogenic risk and the effect on other normal tissues should be assessed in the establishment of therapeutic plan.

Objective To analyze the imaging data of patients with complete clinical remission (cCR) and postoperative pathological complete remission (pCR) after concurrent chemoradiotherapy, aiming to evaluate the values of MRI and rectal ultrasound in predicting pCR. Methods Clinical data of 42 patients with locally advanced rectal cancer treated with concurrent chemoradiotherapy combined with operation were retrospectively analyzed. The magnetic resonance imaging (MRI), endoscopic ultrasound (EUS) and pathological data were statistically compared between patients with cCR and pCR. Results After concurrent chemoradiotherapy,12 patients obtained cCR and 7 patients achieved pCR.The consistency rate of cCR between MRI and EUS was 3/12(25%), and 4/12(33%) for pCR.The consistency rate of pCR of MRI combined with EUS was 5/12(42%). Conclusion Rectal ultrasound combined with MRI cannot fully predict pCR.More accurate detection approach remains to be explored to evaluate the clinical outcomes of watch-and-wait patients.

Objective To discuss the dosimetric advantage of computed tomography-guided interstitial brachytherapy compared with the conventional intracavitary brachytherapy for locally advanced cervical cancer,offering a more advantageous clinical treatment approach. Methods Twenty-eight locally advanced cervical cancer patients with bulky tumors (tumor size>5 cm) after external beam radiotherapy received computed tomography-guided interstitial brachytherapy. Dosimetric outcomes of the current study,including the total dose (external beam radiotherapy+ brachytherapy) D90 for the HR-CTV and D2cc for the bladder,rectum,and sigmoid,were compared with a former patient group consisting of 30 patients who received the conventional intracavitary brachytherapy (uterine tandem+ ovoid pairs). Results The mean D90 value for HR-CTV in the intracavitary brachytherapy group and interstitial brachytherapy group were (76.9±5.7) and (88.1±3.3) Gy,respectively. The D2cc for the bladder,rectum,and sigmoid in the intracavitary brachytherapy group and interstitial brachytherapy group were (84.7±6.8) Gy,(69.2±4.2) Gy,(67.8±4.5) Gy and (81.8±6.5) Gy,(6.8±4.0) Gy,(64.8±4.1) Gy,respectively.1-year local tumor control rate in the intracavitary brachytherapy group and interstitial brachytherapy group were 59.3% and 85.2%,respectively. Conclusions CT-guided interstitial brachytherapy shows a significant dosimetric advantage compared with the conventional intracavitary brachytherapy,and is,thereby,clinically possible feasible. However,the long term curative effect and toxicity need to be further investigated.

Objective To analyze the clinical features and prognosis of extra-nodal nasal NK/T cell lymphoma originated from the larynx. Methods Clinical data of 15 cases of extra-nodal nasal NK/T-cell lymphoma originated from the larynx were retrospectively analyzed. The overall survival (OS) and progression-free survival (PFS) were calculated by Kaplan-Meier survival analysis. The effect of different clinical factors on the clinical prognosis was assessed by univariate analysis. Results Among 15 patients,13 cases were male and 2 female. The median age of onset was 40 years. In 8 cases,the lesions were confined to the larynx,and only 4 cases suffered from cervical lymph node involvement. According to Ann Abor staging,11 cases were classified as grade I,3 as grade Ⅱ and 1 as grade Ⅲ.The median OS was 28.0 months and the 5-year OS was 32.0%.The median PFS was 24.7 months and the 5-year PFS was 33.3%.Among 14 patients with stage Ⅰ/Ⅱ,the clinical prognosis of patients receiving combined chemo-radiotherapy was significantly better than those of their counterparts undergoing radiotherapy or chemotherapy alone (median OS:37.2 vs.11.2 vs.3.7 months,P=0.004). Conclusion Extra-nodal nasal NK/T cell lymphoma originated from the larynx is extremely rare,predominantly in middle-aged male patients. The general condition is relatively favorable. Patients present with multiple lesions in the early stage and relatively poor prognosis. The clinical efficacy of chemotherapy combined with radiotherapy is probably higher compared with that of radiotherapy or chemotherapy alone.

Thymoma of non-surgical treatment or combined modality therapy must be considered in advanced or unresectable cases, which includes radiotherapy, chemotherapy, targeted therapy and immunotherapy. The first choice of resectable advanced thymoma is surgery followed by adjuvant radiotherapy or chemotherapy. For unresectable advanced thymoma, inducted therapy followed by surgery and adjuvant therapy is a rational pattern. But the best treatment mode is still unclear. We review the effect and prognosis about non-surgical treatment of thymoma recent years, to offer advice about making the best decision in the treatment of thymoma.

For patients with positive sentinel lymph nodes, axillary lymph node dissection (ALND) is the conventional treatment. However, ALND can cause seroma, the upper limb dysfunction, edema and alternative complications. Z0011, IBCSG 23-01 and AMAROS phase Ⅲ randomized controlled clinical trials recommend ALND after sentinel lymph node biopsy in N0 patients, which provides a novel option for axillary lymph node treatment, but also brings new challenges to the decision of adjuvant radiotherapy. In this paper, based upon these three clinical trials and latest literatures related to the risk of axillary lymph node metastasis and recurrence, the therapeutic strategies including surgery and adjuvant radiotherapy for patients with positive sentinel lymph nodes are reviewed and summarized.

Precise implantation of applicator is the key step of brachytherapy in cervical cancer patients. The imaging guidance can guarantee the accuracy of applicator placement. At present, the imaging approaches used to guide the applicator placement mainly include ultrasound, CT and X-ray, and MRI and laparoscopy have been applied in certain institutions. There has been no consensus on the standard imaging technique. In this paper, nearly 50 articles and surveys were reviewed to demonstrate that ultrasound-guided placement is of clinical value and guiding significance. Therefore, the application of ultrasound-guided applicator placement in the brachytherapy for cervical cancer was summarized and reviewed.

Brachytherapy is a key part of radical radiotherapy for cervical cancer. Along with the persistent development of radiotherapy techniques, the combined application of brachytherapy and intensity-modulated radiotherapy (IMRT) has been proposed by scholars for cervical cancer patients presenting with large residual tumors accompanied by parametrial infiltration after IMRT. In this article, recent research progress on IMRT combined with brachytherapy applied in the treatment of cervical cancer was reviewed.

High dose grid radiotherapy (GRID) refers to a single fraction of high-dose radiation (10-25 Gy) in which, beams are divided into multiple small beam lets through a grid collimator or MLC, resulting in non-uniform dose distribution of high and low dose area (“peak-to-valley” effect) in the target volume. Recently, as 3D radiotherapy (3DRT) technology emerged, the 2D GRID has been reconfigured into 3D dose LATTICE whereby high doses are concentrated at each lattice vertex within the radiation target volume with drastically lower dose between vertices through multiple focused non-coplanar beams with different radiation techniques. Compared with 2D GRID therapy, 3D LATTICE shows significant effect on “peak-to-valley” and minimizes radiation to surrounding tissues.Experimental and clinical data have shown that LATTICE therapies can reduce toxicity to normal tissue while stimulating bystander effects, endothelial cell death and immunogenic abscopal effects leading to enhanced killing of tumor cells and further improve the control of the local and distant disease. The clinic experience with LATTICE, although limited, has demonstrated favorable outcomes, especially for treating bulky tumors and palliative intend. The exact mechanism of the clinical advantages by LATTICE is not explicitly known and a more comprehensive biological study and clinical trials are called should be carried out.