Chemoradiotherapy for untreated Masaoka-Koga stage IVB thymic carcinoma: asingle-center retrospective study.

Abstract

Thymic carcinoma (TC) is arare type of amalignant tumor. The optimal treatment for Masaoka-Koga stage IVB TC patients is controversial due to the rarity of the disease. Chemotherapy is still the preferred option, but the outcomes are unsatisfactory. Whether radiotherapy combined with chemotherapy could improve prognosis remains unclear. Untreated stage IVB TC patients who have received first-line chemotherapy were included in the present study. The patients who have undergone surgery were excluded. The primary outcomes were objective response rate (ORR) and progression-free survival (PFS). Sixty-seven patients were included in the study. Atotal of 31patients received chemoradiotherapy (ChemoRT cohort), and the remaining 36patients only received chemotherapy (Chemo cohort). The median follow-up period was 40.3months. The ORR for the ChemoRT and Chemo cohorts was 61.3 and 27.8%, respectively (P = 0.006). Furthermore, PFS (P = 0.003) and OS (P = 0.046) were significantly superior in the ChemoRT cohort. Radiotherapy maintained asignificant favorable effect on PFS in multivariate analysis (P = 0.014), but the effect on OS was insignificant (P = 0.249). There was no advantage in PFS (P = 0.302) in the ChemoRT cohort in patients who received< 4cycles of chemotherapy. In contrast, radiotherapy significantly improved PFS (P = 0.005) in patients who received≥ 4cycles of chemotherapy. Chemoradiotherapy used as the first-line treatment improved ORR and PFS in Masaoka-Koga stage IVB TC patients. Patients receiving more cycles of chemotherapy may have abetter chance to benefit from chemoradiotherapy.