Controversies in the Management of Malignant Thymoma

¹ From the Department of Surgery, State University of New York Health Science Center, Syracuse

The management of most thymomas is relatively straightforward: surgical resection remains the primary mode of therapy. However, the literature contains many contradictory points of view regarding histology and pathology, staging and its usefulness, the need for adjuvant therapy, and recently, the place of video-assisted surgery in the treatment of this tumor. This article is not a comprehensive guide to management but rather explores several of these controversial areas. Conclusions include the following: invasiveness remains the single most consistent factor in predicting outcome; surgery is the treatment of choice for thymoma whenever a complete resection can be accomplished; and incomplete resection may have some advantage over biopsy alone. The preponderance of evidence indicates that all thymomas except completely encapsulated stage I tumors should be treated with postoperative adjuvant radiation therapy in the hope of reducing the incidence of local relapse. Myasthenia can no longer be considered an adverse prognostic factor in thymoma; it may even confer a survival advantage, but this may be due to the preponderance of early-stage tumors discovered incidentally in myasthenic patients. Other associated autoimmune diseases confer a survival disadvantage. Demonstrating the equivalence of minimally invasive thoracoscopic approaches to standard thymectomy will take many years of investigation. Some promising reports on response to chemotherapy have led to the development of a phase II intergroup study to assess the value of chemotherapy in advanced thymoma.