Comparison of survival outcomes among standard radiotherapy regimens in limited-stage small cell lung cancer patients receiving concurrent chemoradiation

Abstract

OBJECTIVES: The optimal radiotherapy dose in concurrent chemoradiation (CRT) for limited-stage small cell lung cancer (SCLC) is controversial. We compared the effectiveness of several high-dose chemoradiation regimens using a large national dataset. MATERIALS AND METHODS: Patients with non-metastatic SCLC treated with concurrent CRT were identified in the National Cancer Database base. Overall survival (OS) of patients receiving dose-fractionation regimens, matching those in the ongoing CALGB 30610 trial [45Gy in 30 fractions (Fx) (45Gy/30Fx), 70Gy in 35 fractions (70Gy/35Fx), and 61.2Gy in 34 fractions (61.2Gy/34Fx)], were compared using Kaplan-Meier analysis and multivariable Cox proportional hazards modeling. RESULTS: We included 1228 patients treated between 1998 and 2006 with CRT. Mean age was 62 years and 50% of patients were women. Radiotherapy dose-fractionation was 45Gy/30Fx in 707 (57.6%), 70Gy/35Fx in 53 (4.3%), and 61.2Gy/34Fx in 468 (38.1%). Overall survival was similar among patients treated with 45Gy/30Fx, 70Gy/35Fx, and 61.2Gy/34Fx, with median survival times of 21.5, 21.5, and 20.2 months, respectively (p=0.438). Older age, male sex, larger tumor size, and more advanced stage were associated with inferior OS on Kaplan-Meier (all p<0.001). Cox proportional hazards modeling adjusting for these factors demonstrated similar OS among patients receiving these three dose-fractionation regimens (p=0.815). CONCLUSIONS: We observed equivalent OS among patients with limited-stage SCLC being treated with three dose-fractionation regimens of concurrent CRT. This supports the use of any one of these regimens while awaiting the results of ongoing randomized trials.