The Clinical Methodology Study Of Target Anatomic Dose Painting Of Sbrt Combined With Art Which Were Applied In Inoperative Late Thymomas

Objective:Preoperative target anatomic dose painting of SBRT(Stereotactic Body Radiation Therapy) and ART(adaptive radiotherapy) combined with concurrent chemotherapy were applied in inoperative late thymomas, and efficiency of the new therapeutic mode was analysed. Exploring the precise preoperative radiotherapy methods in the late thymoma; To establish an new clinical treatment mode of inoperative thymoma.Materials and Methods:We are collected the patients of Sichuan cancer hospital from May,2011 to September,2014 that primary diagnosised with locally adanced thymoma, a total of 9 patients, who diagnosed by histopathologic before treatment, and the WHO pathological classification: B2(n=4),B3(n=3), thymic carcinoma(n=2); Masaoka-koga stage IV(n=9).The preoperative chemoradiotherapy:target anatomic dose painting of SBRT and ART,different targets of lesions and different dose fractionated regions were planned through the art of anatomic-dose painting in the light of tumor volume, shape, and OAR influenced surgical resection; All of the target-dose painting were named with GTV1...n+1 which RT dose of the whole course was divided as follow:(1).GTV1:D80 2.5-5.5Gy/f,qd;(2).GTV2、GTV3:D80 1.8-3.5/f,qd or bid;(3).qd or qd mixed with bid.The whole time of Radiotherapy was 18-35 days,and GTVl...n+l were prescribed with 35-54Gy(BEDα/β10Gy=45-63Gy).ART during the RT were defined as:In accordance with CT/MRI, pericardium and V10-20 of lung were first evaluated under the dose of BEDα/β10Gy=15-25Gy, and then re-plan or n+1 times re-plan were carry out, thus tumor regression and surgeons evaluated shrinkage of lesions associated with the invaded part of pericardium, mediastinal large blood vessels, lung and pleura could be archived, and surgery treatment can be finished via the preoperative previews. Two cycle cisplatin(25mg/m2 d1-3) and pemetrexed(500mg/m2 d1) were combined with preoperative-RT.Then surgery were achieved after 3-4 weeks,0-4 cycles postoperative chemotherapy were individualized deliveried for patients in the light of preoperative status and classification of pathology evaluated by surgeons.Results:All patients were well tolerated after chemoradiotherapy, pre/post operation,no patient occurs grade Ⅲ-Ⅳ RTOG/WHO normal tissue toxic effects. The reduction ratios (%) of tumors were calculated(RECSIT standard), the mean reduction ratio of 42.4%( median:38.5%), all of cases were PR, the total effective rate is 100%. All of cases were accepted operation,8 cases for R0(88.7%), one case for R1. The mean follow-up time was 24.2 months(median:18 months), follow-up rate was 100%.1 year’s tumor control rates is 88.9%,2 years’ tumor control rates is 77.8%; 28 months’OS survival rate was 66.7%.Conclusion:Using preoperative hypo-fractionated RT, ART with dose painting and combined with concurrent chemotherapy for the patients with advance inoperative thymoma, the tumor volume diminished significantly with tolerant toxic effects and improving resection rate, is a kind of alternative treatment options with highly clinical efficiency.