Paraneoplastic syndrome and survival in thymic epithelial tumors (TET): The Indiana University experience.

Abstract

8574 Background: Paraneoplastic syndromes (PNS) are commonly associated with thymic epithelial tumors (TET), especially thymoma. The purpose of this analysis is to examine the clinical impact of PNS in TET. Methods: Patients with pathologically diagnosed TET at a single institution were reviewed retrospectively. The primary and second endpoints for this study were overall survival (OS) and recurrence rates. Clinical factors included age, gender, race, performance score, histology, WHO classification, Masaoka stage, post-operative status, tumor size and number of positive lymph nodes. Cox proportional hazards model was used to identify significant prognostic factors for OS between different PNS groups. Results: From 1975 to 2016, 733 patients with TET (thymoma (T) -71%, thymic carcinoma (TC) -26% and neuroendocrine tumor (NET)-3%) were seen at Indiana University. Of these, 203 (28%) had PNS including myasthenia gravis (n = 130), red cell aplasia (n = 20), hypogammaglobulinemia (n = 14), systemic lupus erythematosus (n = 12) or other PNS (n = 64). Among these, 37 (18%) had two or more types of PNS. PNS were seen in 35% (183/523) of T, 9% (16/187) of TC and 15% (3/20) of NET ( p < 0.001), respectively. Recurrence rates and mortality at 5 year were 8% and 10% in PNS (+) group compared to 13% and 16% in PNS (-) group ( p < 0.05). Intrathoracic recurrences were more common in PNS (+) patients (89% vs 77%; p = 0.016). In both groups, adverse factors for survival included: older age, advanced stage, number of positive lymph nodes and TC histology (all p-values < 0.05). However, post-operative R1/2 status was adverse prognostic factor only in the PNS (-) group ( p = 0.001). Conclusions: PNS is common in TETs. Patients with PNS have lower risk of recurrence and mortality compared to patients without PNS, but may have a higher risk of intrathoracic recurrence.