MA 16.08 Surgery for Pleural Dissemination of Thymoma; A 20-Year Experience

Surgical management of pleural dissemination of thymoma has been recommended in some reports, while reports on the long- term results of pleural dissemination resection are few. The aim of this study was to assess mid- and long- term results of surgical resection of pleural dissemination of thymoma. We retrospectively analyzed data from patients with synchronous or metachronous pleural dissemination and primary thymoma who underwent surgical resection between 1996 and 2016 in our hospital. During the study period, 38 patients underwent resection of pleural dissemination of thymoma. The synchronous group consisted of 21 patients with a median age of 50.2 years (range: 28—75 years) at the time of resection. The metachronous group consisted of 17 patients with a median age of 46.7 years (range: 30—65 years) at the time of resection of pleural dissemination. The median follow-up was 72.7 months (range: 3—248 months). In the synchronous group, 19 patients were in stage IVa and 2 patients were in stage IVb. The histological type of thymoma was type B1 in 3 patients, type B2 in 9 patients, typeB3 in 9 patients. In the metachronous group, Masaoka stage of the primary thymoma was as follows; 3 patients were in stage I, 5 patients were in stage II, 7 patients were in stage III and 2 patients were in stage IVb. The histological types of the resected dissemination nodule were type AB in 1 patient, type B1 in 1 patient, type B2 in 5 patients, and typeB3 in 10 patients. A macroscopic complete resection of pleural dissemination was achieved in 30 patients (79%) of all the patients. No perioperative deaths occurred. Postoperative complications occurred in 5 patients (13.2%). During the observation period, 5 patients died (relation to the tumor in 4) in the synchronous group and 1 patient died (unrelated to the tumor) in the metachronous group. The 5- and 10-year overall survival rates of all the patients were 87.6% and 69.2%, respectively. Of all the patients, 14 received repeated resection of the pleural disseminated nodule. The 5- and 10-year overall survival rates from the first resection of pleural dissemination were 76.6% and 46.0% in the non-repeat resection group and 100% and 88.9% in the repeat resection group, respectively. Surgery for pleural dissemination of thymoma was safely performed and provides favorable prognosis. Repeat resection for pleural dissemination could be effective in achieving a prolonged survival.