Multicenter institutional experience of surgically resected thymic epithelial tumors (TETs): an observational report on behalf of F.O.N.I.C.A.P. (Forza Operativa Nazionale Interdisciplinare Contro il Cancro del Polmone).

Background: This multicenter analysis evaluated patient outcome and clinical pathologic features of thymic epithelial tumors after complete surgical resection and adjuvant treatment.

Methods: Histologic classification and clinical staging were performed according to WHO classification and Masaoka staging system, respectively.

Results: We analyzed 62 patients, 20 (32%) of whom had myasthenia at diagnosis. Clinical and pathologic staging was as follows: 31 (50%) and 30 (48%) patients had stage I disease, 19 (30%) and 22 (35%) stage II, 5 (8%) and 3 (6%) stage III, 2 (4%) and 2 (3%) stage IVa, and 5 (8%) and 5 (8%) stage IVb, respectively. Histologic examination revealed 11 (19%) type A tumors, 19 (30%) type AB tumors, 7 (12%) type B1 tumors, 11 (17%) type B2 tumors, 11 (17%) type B3 tumors, and 3 (5%) type C tumors. Adjuvant therapies comprised chemotherapy in 3 (5%) patients and radiotherapy in 16 (26%) patients. Median follow-up was 71 months (range 1-145). DFS and OS at 48, 60, and 72 months were 89 and 89%, 86 and 97%, and 95% and 92%, respectively. Myasthenia at the onset of disease (P=0.18 for DFS; P=0.97) and tumor size>5 cm (P=0.94 for DFS; P=0.56) were not prognostic factors.

Conclusions: TETs are rare and indolent tumors. Complete surgical resection followed by adjuvant therapies, such as chemotherapy and/or radiotherapy, in patients at risk of recurrence show very good DFS and OS results, even in cases with radically resected pleural-pulmonary metastases.