Association of thymoma and myasthenia gravis: oncological and neurological results of the surgical treatment☆

Abstract

Thymoma occurs in about 10-20% of myasthenic patients and in turn, 20-25% of patients with a thymoma have myasthenia gravis. Both diseases are treated by surgery. The aims of this study were to analyze the clinical features of these patients and the oncological and neurological outcomes after thymectomy. Clinical and pathological data, complete remission rate as well as overall survival rates were retrospectively analyzed in a cohort of myasthenic patients who underwent extended thymectomy for thymoma between 1993 and 2006. One hundred and twenty-three patients (60 m and 63 f) with a mean age of 56 years (range 22-83) underwent extended thymectomy. The WHO histological classification was: A in 22 cases, AB in 18, B1 in 33, B2 in 22, and B3 in 28. The Masaoka clinical staging was: I in 10 cases, IIA in 33, IIB in 50, III in 14, IVA in 15, IVB in 1. We experienced 2 postoperative deaths. With a overall mean follow-up of 76 months 42 patients had a complete remission, 39 a remission with medications, 35 an improvement of the symptoms, 3 remained nearly in the same status and 4 worsened. At the last follow-up, 112 patients were alive; 11 with disease. Four deaths were related to the tumor. Actuarial 5- and 10-year survival was 93.4% and 79.6%, respectively. Neurological outcome of the extended thymectomy in myasthenic thymoma patients was satisfactory. Higher complete remission rate is expected in early stage thymoma. Regarding the overall survival it was dependent on the Masaoka stage, the WHO classification and the achievement of complete remission of myasthenic symptoms.