Small cell lung cancer (SCLC) is an aggressive disease treated as soon as possible given its rapid doubling time. Evidence for the appropriate time to chemotherapy initiation (TCI) for SCLC is lacking. This study evaluated TCI in SCLC on a national level.
Materials and Methods:
The National Cancer Database identified 64,491 SCLC patients treated with chemotherapy from 2010 to 2014. Factors associated with TCI were identified with multiple linear regression analyses. TCI was categorized into 4 groups using cutoff points of 7, 14, and 28 days. Using these categories, median overall survival and log-rank test was used for univariate analysis of the survival outcome and the Cox model was used for multivariate analysis.
Median TCI was 18 days with 21% treated ≤7 days, 21% in 8 to 14 days, 30% 15 to 28 days, and 28% >28 days from diagnosis. Younger age, white race, no insurance, more comorbidities, and higher stage were associated with shorter TCI. Median overall survival for TCI within 7 days was 8.2 months, 8 to 14 days was 9.2 months, 15 to 28 days was 10.3 months, and > 28 days was 10.8 months (P<0.001). In the multivariate analysis, increased TCI was associated with improved survival across all stages. Among stage IV patients, compared with TCI≤7 days, the hazard ratio (HR) is 0.92 (P<0.001) for 8 to 14 days, HR 0.82 (P<0.001) for 15 to 28 days, and HR 0.77 (P<0.001) for >28 days of TCI. Results were similar for stage III and for stages I+II.
Our results show worse survival with shorter TCI. This provides evidence to inform a discussion regarding appropriate treatment timing and individualizing treatment.