Invasive thymoma: treatment with postoperative radiation therapy.

Abstract

To assess radiation therapy and chemotherapy in the treatment of invasive thymoma and thymic carcinoma. In 1981-1995, 43 patients received irradiation after total (n = 23) or subtotal (n = 20) resection. Tumors were thymic carcinoma (n = 10) or invasive thymoma (n = 33). Masaoka stage was II in 10 patients, III in 14, and IV in 19. Median total dose applied was 50 Gy (range, 10-72 Gy). Seventeen patients (five with stage III and 12 with stage IV) also received chemotherapy. Patients with thymic carcinoma had a median survival of 9.5 months, compared with 50 months for patients with invasive thymoma (P = .008). Patients' median survival and 5-year survival rates were 97 months and 90% for stage II, 65 months and 67% for stage III, and 32.5 months and 30% for stage IV tumors (P = .024). Overall control rate within the radiation field was 81% (35 patients) and overall local control rate within the thorax was 74% (32 patients). Of the 17 patients who received chemotherapy and radiation therapy, nine had thymic carcinoma and a median survival of 12 months (range, 1.4-23.0 months). With total doses of 45-50 Gy, local control is achievable after radical resection. Whether patients with completely resected stage II thymomas should receive radiation after surgery remains uncertain, as does the role of chemotherapy in the treatment of thymoma.