P2.04-024 Thymic Epithelial Tumors and Radiotherapy Results: Topic: Thymic Malignancies Clinical and Translational

Abstract

Thymic epithelial tumors (TET) treated with radiotherapy (RT) was evaluated for treatment outcomes and prognostic factors on survival. Between October 1995 and December 2013, 31 patients were treated. The median age was 44 (range: 19-83). There were 25 thymoma, 4 thymic carcinoma (TC) and 2 thymic neuroendocrin carcinoma (NEC). The incidence were found 13%, 39%, 39% and 9% for Masaoka stage I-II-III and IV, and 3%, 16%, 61%, 13% and 6%, for WHO type A-AB-B-C and NEC, respectively. Eighteen patients (58%) underwent R0 resection. Median RT dose was 5400 cGy (range: 1620-6596). Seven patients received a median of 6 cycles (range: 1-6) cisplatin-based adjuvant and 4 patients received weekly 60-70 mg/m2 paclitaxel or 2-3 cycles standard chemotherapy concurrently. According to prognostic risk stratification including Masaoka staging and WHO classification, cases were divided to good (n: 10), moderate (n: 9) and poor (n: 12) risk groups. Survival was calculated from diagnosis. In January 2016, 22 cases lived with median 51.5 months (range: 2-170.5) follow-up. Recurrences were observed 9 (29%) of patients median 29.5 months (range: 6.5-105). Local control, mean overall (OS) and disease-free survival (DFS) rates for all patients, were 86%, 119 months (range: 94-144) and 116 months (range: 89-144), respectively. Local control were 100%, 89% and 75% for good, moderate and poor risk groups, respectively (p=0.08). There were a significant differences for Masaoka stage (I-II vs III-IV, p = 0.001, p <0.001), R0 resection (present vs absent, p = 0.06, p = 0.05), histology (thymoma vs TC, p = 0.02, p = 0.01) and prognostic risk groups (good vs moderate vs poor, p = 0.003, p = 0.004) in terms of OS and DFS, respectively. In our study, prognostic risk stratification was seen to be an important predictor for survival. The patients with TC was stage III-IV at diagnosis in moderate and poor risk groups indirectly and survival rates was found to be less than thymoma.