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

Thymic tumors—typically diagnosed in middle-aged patients—are rare, comprising only 0.2–1.5% of all mediastinal neoplasms; indeed, incidence is 0.15 per 100,000 person-years in the United States (1,2). The approach to treatment is controversial, although radical thymectomy with complete tumor resection is commonly accepted as standard procedure when thymoma is associated with myasthenia gravis (MG) (3-5), an event occurring in about 45% of cases (6). Moreover, most of the investigators indicate that radical thymectomy should be standard also for non-myasthenic thymoma as well as thymic carcinoma because less-extensive surgery can be associated with increased risk of local recurrence, as thymic tissue within mediastinal fat can represent possible foci of occult cancer (3,7). However, some series indicate that conservative surgery (thymomectomy without radical thymectomy) for non-myasthenic thymoma is not associated with a worse outcome (4,8,9); indeed, in a 2016 study by Tseng et al. (4) of stage I–II nonmyasthenic thymoma patients receiving extended thymectomy via median sternotomy (n=42), thymomectomy without thymectomy via video-assisted thoracoscopic surgery (VATS) (n=22), or thoracotomy (n=31), found that recurrence rates were always low (n=1 in the thymomectomy group; n=2 in the thymectomy group) and did not differ significantly between interventional groups after a mean follow-up of 57 months (range, 6–121 months). The authors concluded that thymomectomy without thymectomy is justified for early-stage non-myasthenic thymic tumors, but acknowledged the need for a longer follow-up. To our knowledge, no prospective analyses have compared thymomectomy with radical thymectomy in non-myasthenic patients with thymic tumors