Radical thymectomy versus conservative thymomectomy in the surgical treatment of thymic malignancies

Complete thymectomy is recommended for thymic malignancies to reduce local recurrence and the likelihood of the long-term development of myasthenia gravis (MG). Thymus-conserving surgery (thymomectomy) seems to yield similar results, but evidence is still limited. The objective of this study was to assess if the oncological outcome, in terms of overall survival (OS) and disease-free survival (DFS), are comparable between radical thymectomy vs. conservative thymomectomy patients, and to assess if the outcome of the video-assisted thoracoscopic surgery (VATS) approach was similar to open surgery approach.

We retrospectively analyzed 157 consecutive patients with either resectable thymoma or thymic carcinoma from two Italian centers (Humanitas Research Hospital, Milan, and Humanitas Gavazzeni, Bergamo) between 1997 and 2013 who underwent thymomectomy or extended thymectomy with the VATS or open approach; the patients with Miastenia Gravis underwent radical thymectomy. The patients were followed through physical examinations and phone interviews.

Thymomectomy and thymectomy were performed on 86 (54.8%) and 71 (45.2%) patients, respectively. Prognostic factors and comorbidities were comparable in the two groups. The median follow-up was 77 months. Cox proportional hazards model revealed that Masaoka advanced stage and thymic carcinoma of WHO classification were independent predictive factors for overall survival, but that the extent of surgery and the approach used (minimally invasive versus open) were not. Notably, five- and ten-year survival rates were similar in the two groups.

In our experience, radical thymectomy and conservative thymomectomy did not differ in terms of disease-free and overall survival rates. In nonmyasthenic patients with early-stage resectable thymic malignancy, minimally invasive thymomectomy provided equivalent results to open thymectomy. Our results should be interpreted with caution due to the retrospective nature of the study. Well-designed, adequately-powered studies should be very welcome to increase the quantity and the quality of clinical evidence before incorporating this procedure in future guidelines.