Long-term results of surgical treatment for invasive thymoma

Background: The aim of this study was to analyse the operative outcome of extensive surgery for invasive thymoma and to assess the prognostic factors for long-term survival. Materials and Methods: Forty patients with invasive thymoma have been operated on at our institution during past the 33 years. We performed total removal of the tumour, including invaded neighboring organs. Complete resection was performed in 27 patients, incomplete resection in 4. Nine patients had unresectable thymoma. Postoperative radiotherapy was performed in 30 patients with a median dose of 48 Gy. Results. The 10-year survival rate was 72% for Masaoka stage II, 47% for stage III, and 0% for stage IV. There was no postoperative mortality. Conceming the prognostic factors for long-term survival, there were no significant differences in the analysis of Masaoka staging, histological classification, association of autoimmune disease, and postradiotherapy. However, the survival rate was significantly higher for patients with complete resection than for patients with incomplete resection or biopsy only (p=0.019). Conclusions: Whether the tumour is resected completely or not is the most important factor for long-term survival; therefore it is preferable to perform extensive surgery for invasive thymoma.