Clinical Characteristics and Outcomes for Patients With Thymic Carcinoma: Evaluation of Masaoka Staging

Abstract

Thymic carcinomas are rare cancers with limited data regarding outcomes, particularly for those patients with advanced disease. We identified patients with thymic carcinomas diagnosed between 1993 and 2012. Patient characteristics, recurrence-free survival (RFS), and overall survival (OS) were analyzed. One hundred twenty-one patients with thymic carcinomas were identified. Higher Masaoka stage was associated with worse OS and RFS (5-year OS of 100%, 81%, 51%, 24%, and 17% for stage I, II, III, IVa, and IVb respectively, p < 0.001 and 5-year RFS of 80%, 28%, and 7% for stage I/II, III, and IV respectively, p < 0.001). Patients with stage IVb lymph node (LN) only disease had a better 5-year OS as compared with patients with distant metastasis (24% versus 7%, p = 0.025). Of the 61 patients with stage IVb disease, 22 of 29 patients (76%) with LN-only disease underwent curative intent resection versus 3 of 32 patients (9%) with distant metastasis. Twenty-two patients with LN involvement were treated with multimodality therapy. Three (14%) remain free of disease with long-term follow-up (range, 3.4+ years- to 6.8+ years). We describe the clinical features of a large series of patients with thymic carcinoma in North America. The Masaoka staging system effectively prognosticated OS and RFS. Patients with stage IVb LN-only disease had significantly better OS as compared with patients with distant metastasis with a subset of patients sustaining long-term RFS with multimodality therapy. If validated, these data would support a revised staging system with subclassification of stage IVb disease into two groups.