Thymectomy for myasthenia gravis: Complete stable remission and associated prognostic factors in over 1000 cases

Objectives The efficacy of thymectomy and the optimal surgical technique in the treatment of myasthenia gravis remain controversial. Long-term outcomes are lacking and remission rates are based on small populations. We reviewed our institutional experience of thymectomy for myasthenia gravis focusing on long-term outcomes, complete stable remission, improvement of symptoms, after transcervical, trans-sternal, thoracotomy, and VATS thymectomy. Methods a retrospective review of a prospectively maintained database of 3017 patients from 1941-2013 with myasthenia gravis was performed. Patients who underwent thymectomy with follow-up data including: age at time of surgery, gender, date of onset of symptoms, date of surgery, Osserman Classification before and after surgery, surgical technique, date of remission, and status at last follow-up were included in the analysis. Complete stable remission and prognostic factors were analyzed by crude rate, Kaplan-Meier estimate, Chi squared test, Wilcoxon test, and a Cox proportional model. Results 1002 thymectomy patients with complete data were analyzed. 35.5% (n=355) derived benefit from surgery. Crude rate complete stable remission was 19% (n=191) and an additional 16% (n=164) symptomatically improved requiring less medication after thymectomy. 58% (n=580) were stable after resection and 6.7% (n=67) developed progressive disease. Kaplan-Meier estimates of complete stable remission were 27.7%, 36.7%, and 47.3% at 10, 25, and 40 years, respectively. On multivariate analysis, transsternal technique, thymoma, and preoperative Osserman classification were significantly associated with failure to achieve complete stable remission. Conclusions Thymectomy provides long-term complete stable remission in 47.3% of patients with long-term follow-up. Myasthenia gravis patients should be offered thymectomy when possible. Central Trial Registry Number None