P2.15-12 Epidemiology of Thymic Epithelial Tumors: 22-Year Experience from a Single-Institution

Abstract

Thymic epithelial tumors (TETs) represents a heterogeneous group of rare neoplasms that represent, however, the most common entity of the anterior mediastinum. Epidemiological data and treatment options for these neoplasms are very limited. Retrospective study of TET diagnosed at Instituto Nacional de Enfermedades Neoplasicas (INEN) in Lima, Peru, from 1996 to 2018. Clinicopathological data was retrieved from clinical files. All cases were reviewed by a pathologist and reclassified according to the 2004 WHO classification system. Staging was performed with the Masaoka-Koga Staging System. Treatment and follow-up data were also collected. Survival curves were constructed with the Kaplan-Meier method. 84 patients were included. Median age at diagnosis was 55 years old (range 19 to 84) and 51.8% were female. Most patients (95.2%) were in good status performance (Zubrod 0-2) and 36.5% were smokers. The histological type corresponded to thymoma (T) in 63.9% of cases (n=53) and to thymic carcinoma (TC) in 36.1% of cases. T were of type A, AB, B1, B2 and B3 in 15.8%, 19.7%, 3.2%, 3.9% and 7.9% of cases, respectively. The proportion of advanced disease (Masaoka stage III-IV) was higher in TC (89.6%) than in T (51.1%). The most common treatment modality was systemic chemotherapy for advanced disease in 37.3%. With a median follow-up of 88.4 months, median overall survival (OS) was 81.6 months for T and 12.3 months for TC (p=0.01). Survival according to different histological types is shown in table 1.Tabled 1Histological typeMedian OS (months)Thymoma A, AB, B1102Thymoma B2 – B316.7Thymic carcinoma12.3 Open table in a new tab The result of this study indicates a clear association between the WHO histological classification and Masaoka-Koga staging system with survival. We found a higher than expected proportion of T with advanced disease at diagnosis. The reasons behind this finding require further research. Being this a rare disease, collaboration is very important to foster knowledge and to promote prospective and randomized clinical trials focused on classification and treatment.