525PRetrospective analysis of outcomes of cisplatin and irinotecan combination chemotherapy for unresectable thymic carcinoma

Abstract Background Thymic carcinoma is a rare, malignant mediastinal tumor originating from thymic epithelial cells. It exhibits a tendency for metastasis and invasive growth. Unresectable thymic carcinoma is treated with systemic chemotherapy. However, a definitive chemotherapeutic regimen for this entity is yet to be established. The objective of this study was to evaluate the efficacy and safety of cisplatin and irinotecan combination as the first-line chemotherapy. Methods Data pertaining to patients with advanced thymic carcinoma who received cisplatin and irinotecan combination chemotherapy between January 1, 2002 and December 31, 2018, were retrospectively analyzed. The end points were disease control rate, progression free survival, and overall survival. The incidence of significant hematological and non-hematological toxicity was also assessed. Results We identified 17 patients with a median age of 56 years (ECOG performance status: 0 or 1). All patients had clinical stage (Masaoka-Koga staging system) IVa or IVb. Disease control was achieved in 15 patients (88.2%). Median progression-free survival was 7.3 months [95% confidence interval (CI) 2.7–11.6]; median overall survival was 45.6 months (95% CI 9.49–69.5). The outcomes were similar to those achieved with previously reported chemotherapy regimen, CBDCA plus paclitaxel or Cisplatin combination chemotherapy. No treatment-related deaths occurred in this cohort. Grade 3 or worse hematological toxicity was observed in five patients (neutropenia: three patients; anemia: two patients); grade 3 or worse non-hematological toxicity was observed in three patients. None of the patients developed febrile neutropenia. Conclusions Cisplatin and Irinotecan combination chemotherapy may be a safe and effective first-line chemotherapy regimen for unresectable thymic carcinoma. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure Y. Hosomi: Honoraria (self): AstraZeneca. All other authors have declared no conflicts of interest.