Does myasthenia gravis influence overall survival and cumulative incidence of recurrence in thymoma patients? A Retrospective clinicopathological multicentre analysis on 797 patients.

Abstract OBJECTIVE: Aim of this study is to evaluate whether Myasthenia Gravis (MG) might influence Overall Survival (OS) and Cumulative Incidence of Recurrence (CIR) in thymoma patients. METHODS: this is a multicenter retrospective study of patients operated in 6 high-volume Italian Institutions between 1990 and 2012. OS was estimated by the Kaplan-Meier method and CIR by considering death from any cause as a competing event. Crude and adjusted comparisons by MG for OS and CIR were performed using Cox and Fine&Gray models. Adjusted models included MG, age, gender, stage, histology, induction therapy, completeness of resection, adjuvant therapy. RESULTS: Seven hundred ninety-seven patients were included: 375 (47%) had MG. MG patients were younger and more frequently female, with a B2-B3 thymoma. At the end of the study, 129 patients (54 with MG) developed a recurrence and 165 (66 with MG) died. At univariate analysis, MG showed a slight protective effect on OS, not confirmed by the