Thymic carcinoma: 30 cases at a single institution

Introduction: Thymic carcinoma is a rare and invasive mediastinal neoplasm that often metastasizes. It constitutes a heterogeneous group of tumors that displays different biologic behavior and prognosis. The clinical prognostic factors and treatment of thymic carcinoma are not yet standardized. Methods: Thirty patients with thymic carcinoma have been treated at Nagoya City University Hospital since 1983. The clinical and pathologic data of these patients were retrospectively reviewed. Thirteen cases were considered to be unresectable or inoperable and received chemotherapy or chemoradiotherapy. Seventeen cases underwent resection; total in 7 cases and subtotal in 10 cases. Postoperative irradiation was added as adjuvant therapy in the tolerable cases. The most recent five cases received induction chemotherapy. Results: In 17 of the 30 cases, the patients died. The survival periods in the death cases were from 2.4 to 78.1 months (mean, 32.4 months; median, 21.0 months). The observation periods in the 13 live cases were 6.3 to 232 months (average follow-up, 64.6 months). The 5-year survival rate was 47.5%, and median survival time (MST) was 49.0 months. Cases that underwent total resection showed significantly better prognosis than cases with subtotal resection (p = 0.011) and inoperable cases (p = 0.002). The cases that underwent subtotal resection showed significantly better prognosis than the inoperable cases (p = 0.050). The cases with hematogenous metastasis demonstrated significantly poorer prognosis (p = 0.021), but lymphogenous metastasis was not a significant predictor of poor prognosis. Only resectability was a significant prognostic factor in multivariate Cox regression analysis, and the hazard ratio was 5.123. Conclusions: Resectability was the only prognostic factor in thymic carcinoma. We suggest the importance of preoperative precise evaluation to exclude unresectable Masaoka stage IVb disease and expect preoperative chemotherapy or chemoradiotherapy to improve the respectability.