Thymic tumors and results of radiotherapy

Abstract

Aim

The aim of this study was to evaluate thymic epithelial tumors (TETs) for treatment outcomes and prognostic factors on survival.

Background

TETs are very rare neoplasms and multidisciplinary approach is recommended according to prognostic factors.

Materials and methods

Between 1995 and 2013, 31 patients were treated with median 5400[[ce:hsp sp="0.25"/]]cGy (range: 1620–6596[[ce:hsp sp="0.25"/]]cGy) radiotherapy (RT). Eleven patients received adjuvant or concurrent chemotherapy. There were 25 thymomas, 4 thymic carcinomas and 2 thymic neuroendocrin carcinomas. According to Masaoka, staging and WHO classification, cases were divided to good (n: 10), moderate (n: 9) and poor (n: 12) prognostic risk groups. Survival was calculated from diagnosis.

Results

In January 2016, 22 cases were alive with median 51.5 months (range: 2–170.5) follow-up. Recurrences were observed in 29% of patients in median 29.5 months (range: 6.5–105). Local control, mean overall (OS) and disease-free survival (DFS) rates were 86%, 119 and 116 months, respectively. There was a significant difference for R0 vs. R+ resection (81% vs. 43%, p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.06, and 69% vs. 46%, p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.05), Masaoka stage I–II vs. III–IV (75% vs. 52%, p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.001, and 75% vs. 37%, p[[ce:hsp sp="0.25"/]]<[[ce:hsp sp="0.25"/]]0.001), and also prognostic risk groups (100% vs. 89% vs. 48%, p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.003, and 100% vs. 87% vs. 27%, p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.004) in terms of 5-year OS and DFS, respectively.

Conclusion

In our study, prognostic risk stratification was shown to be a significant predictor of survival. There is a need to investigate subgroups that may or may not benefit from adjuvant RT.