Introduction: Peripheral T-cell lymphomas (PTCL) represent a heterogeneous group of neoplasms with an aggressive biological course and a poor clinical outcomes. Unfortunately, despite its less than satisfactory results, cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) remains de facto standard, as there lacks evidence of other regimens being superior. Contradicting results have been reported on the role of etoposide in treatment of T-cell lymphomas. In this study, we aimed to thoroughly analyze the impact of incorporating etoposide to first-line treatment in a large population-based cohort of systemic PTCL patients. Methods: Using the merged data from the Korean National Health Insurance Service (NHIS) and National Cancer Registry, all patients diagnosed with non-cutaneous, non-leukemic adult PTCL patients (>20 years old) between January 1, 2002, and December 31, 2010, were identified. After excluding 311 patients for not receiving any treatment or insufficient data, a total of 1933 patients were evaluated for clinical characteristics and treatment outcomes. Results: There were 1075 mature T-cell lymphomas (55.6%), 445 angioimmunoblastic T-cell lymphomas (23.0%), 326 anaplastic large cell lymphomas (16.9%) and 40 intestinal T-cell lymphomas (2.1%). The median age at PTCL diagnosis was 58 (range 46–68 years). Approximately, 38.7% (748) of the 1933 patients received CHOP or CHOP-like regimes (CVP, hyperCVAD/MA), 35.1% (678) received CHOP-like regimen plus etoposide, 5.9% (113) underwent other backbone chemotherapy plus etoposide, and 20.3% (394) underwent other treatments. The patients were divided into 3 groups according to their first-line treatment for outcome analyses: group 1, CHOP or CHOP-like regimens; group 2, CHOP or CHOP-like regimens plus etoposide; and group 3, all others. Group 1 was associated with longest PFS (P < 0.001) and OS (P < 0.001). Even when adjusted for lymphoma stage, age and underlying condition, addition of etoposide remained an unfavorable prognostic marker for both PFS (HR 2.432, P = 0.0076) and OS (HR 1.303, P = 0.0374). Adding etoposide led to longer hospitalization day and cytopenias requiring transfusion (Table). Conclusions: This is one of the largest population-based PTCL cohort and provides important information on outcomes of PTCL outside of clinical trials setting. Addition of etoposide to CHOP-like regimens does not warrant better PFS nor OS for PTCL patients, regardless of age at diagnosis. Acknowledgement: This study was supported by the National Cancer Center, Korea (NCC-1632080). PFS, progression free survival; OS, overall survival; tf, transfusion. Keywords: etoposide; peripheral T-cell lymphomas (PTCL); T-cell lymphoma (TCL).