Clinical and pathologic predictors of survival in patients with thymic tumors.

BACKGROUND: The aim of this study is to evaluate the impact of thymectomy in patients with thymic neoplasms and to identify clinical and histopathological factors associated with improved long-term outcome of surgery. METHODS: We treated 74 patients between February 1987 and July 1993. There were 29 total and 36 simple thymectomies. These last cases, all non-myasthenic, had benign thymomas (n=30) but 6 had thymic carcinomas. Nine tumors were no-resected (5 thymomas and 4 thymic carcinomas). Minimum follow-up by Department of Thoracic Surgery Istituto Nazionale Tumori was 60 months after thymectomy. We divided the specimens according to Marino and Muller-Hermelink's classification: 54 thymomas, 18 thymic carcinomas and 2 no-diagnosis specify thymomas. There were 53 stage I, 1 stage II, 13 stage III, 5 stage IVa and 2 stage IVb according to Masaoka. RESULTS: Forty-six patients with treated thymoma were alive without disease at the end of follow-up, the remaining 8 died from recurrence in 6, a new tumor in 1 and a heart attack in the last. Of 18 thymic carcinomas 9 were alive at the end of follow-up (1 with recurrence), only 4 dead from recurrence. The actuarial survival of patients with thymomas was 88.5% at 5 years, (73.6% in cortical type, 85.7% in medullary type, 93.9% in mixed type, 100% in predominantly cortical type). Myasthenia gravis didn't influence the survival: 87.3 (no MG) vs 90%. Advanced stage thymomas significantly increased the risk of death from early stage I: 32.4 vs 100% at 5 years. In thymic carcinoma patients with well-differentiated thymic carcinoma (WDTC) died less than others: the actuarial probability of survival at 5 years was 90 vs 68%. CONCLUSIONS: Thymectomy was the best treatment to long term outcome. In our experience, survival was related to histotype and to local extension of tumor.