Abstract
PurposeSmall cell lung cancer (SCLC) is a highly fatal disease, but its treatment has remained relatively unchanged for decades. Randomized clinical trials evaluating radiation therapy (RT) dosing and fractionation have yielded mixed results on overall survival (OS). Methods and MaterialsWe identified 2261 patients with limited-stage (LS) SCLC undergoing definitive RT at 1.5, 1.8, and 2.0 Gy dose per fraction, concurrently with chemotherapy, between 2004 and 2015 within the National Cancer Database. Overall survival (OS) was evaluated using the Kaplan-Meier method, and Cox proportional hazards regression was used to investigate whether there was any survival difference among patients who received hyperfractionated, twice-daily RT at 1.5 Gy per fraction (HF1.5) and once-daily, standard fractionation RT at 1.8 Gy (SF1.8) or 2.0 Gy (SF2.0) per fraction. Subgroup analyses by age, sex, race, time to RT, facility type, and Charlson comorbidity index were also performed. ResultsAll stage median OS rates for HF1.5, SF1.8, and SF2.0 Gy groups were 21.6, 18.9, and 19.4 months, respectively (log-rank P = .0079). Multivariate analyses adjusting for demographic factors, socioeconomic status, tumor characteristics, and year of diagnosis showed SF1.8 (hazard ratio [HR] = 1.30, 1.03-1.63) and SF2.0 (HR = 1.20, 1.00-1.45) was associated with worse 1-year survival compared with HF1.5. This association was more evident in stage IIb-stage III than stage I to stage IIa patients. Propensity score–weighted analysis showed similar results. Stratified analyses showed the significant associations were confined to male or black patients, those aged >65 years, with 1 comorbidity, who had waited >60 days to start RT or were treated at an academic medical center. ConclusionsAnalyses of real-world treatment outcome data showed that receiving hyperfractionated, twice-daily RT was associated with improved survival among patients with LS-SCLC compared with standard, once-daily fractionation regimens at 1 year after diagnosis, particularly for subsets of patients. Some associations retained statistical significance 3 years postdiagnosis.
Highlights
Surgical resection followed by adjuvant chemotherapy has been reported to improve survival in LS-Small cell lung cancer (SCLC) patients without nodal involvement and may present a superior treatment strategy compared with concurrent chemoradiotherapy (CCRT) in these highly selected cases
In our retrospective study analyzing real-world treatment and outcome data from the National Cancer Database (NCDB), we found that LS-SCLC patients who received daily, standard fractionations of 1.8 Gy and 2.0 Gy per fraction had worse survival compared with those who received hyperfractionated RT at 1.5 Gy
propensity scores (PS) weighted regression showed similar results to those from multivariate analyses. These results suggest that more patients with locally advanced, LS-SCLC, treated with BID fractionation, survive to 1- and 3-year intervals, even though they may succumb to their disease, at rates comparable to their counterparts treated on daily fractionation regimens
Summary
We identified 2,261 limited-stage (LS) SCLC patients undergoing definitive RT at 1.5, 1.8, and 2.0 Gy dose per fraction, concurrently with chemotherapy, between 2004 and 2015 within the National Cancer Database. Sex, race, time to RT, facility type, and Charlson comorbidity index were performed
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