Comparison of once and twice daily radiotherapy for limited stage small-cell lung cancer

Purpose: This study was designed to review outcomes of once- (QD) versus twice-daily (BID) radiotherapy (RT) for limited stage small-cell lung cancer (L-SCLC) treated at Dana-Farber Cancer Institute/Brigham and Women's Hospital. Methods: We reviewed records for all patients with L-SCLC treated with radical chemoradiotherapy at our institution between January 2005 and December 2010. Differences in patient, tumor, and treatment characteristics were assessed by Student's t test and Fisher exact test. Outcomes were compared using Kaplan-Meier estimates and Cox proportional hazards regression. Results: Twenty patients received QD RT to a median dose of 61.2 Gy, and 26 patients received BID RT to a dose of 45 Gy. Median follow-up was 2.8 years. Overall survival (OS) was similar in both groups. 5-year locoregional control (LC) for all patients was 67 %: 80 % for the QD group and 57 % for the BID group (log-rank, P = 0.16). Grade 2 or higher dermatitis and pneumonitis were significantly higher in the QD group (15 vs. 0 %, P = 0.0014 and 13 vs. 4 %, P = 0.048, respectively), whereas Grade 2 or higher esophagitis trended higher in the BID group (44 vs. 24 %, P = 0.076). Conclusions: Although there were no differences in OS with QD versus BID RT, there was a trend toward increased LC in the QD group. Dermatitis and pneumonitis were more common for QD RT, and esophagitis was somewhat more common for BID RT. Possible differences in toxicities depending on RT regimen may be worth further investigation, until results from CALGB 30610 become available.