Impact of timing of adjuvant chemotherapy on survival for early-stage node-negative small-cell lung cancer

Background: The relationship between timing of adjuvant chemotherapy and survival for early-stage, node-negative small cell lung cancer is not well defined, and no formal guidelines exist. We sought to evaluate whether increasing the time between surgery and adjuvant chemotherapy for pathologic stage I-IIA SCLC would be associated with worse survival. Methods: The association between timing of adjuvant chemotherapy and survival for patients with pathologic stage I-IIA (pT1-2N0M0) SCLC who have 1 or fewer co-morbidities in the National Cancer Database from 2004-2021 was assessed using multivariable Cox regression analysis with penalized smoothing spline functions and propensity score-matched analysis. Adjuvant chemotherapy received within 21-40 days of surgery was classified as "earlier" while adjuvant chemotherapy received 41-90 days after surgery was classified as "later." Results: Of 927 patients who met study criteria, the median time to adjuvant chemotherapy was 41 days (interquartile range, 34, 53). In multivariable and propensity score-matched analyses, there was no significant difference in overall survival between earlier and later adjuvant chemotherapy. These findings were consistent when limited to patients who were discharged within 4 days of surgery or when adjusting for minimally invasive surgical approaches. Conclusions: In this national analysis of patients with early-stage node-negative SCLC, there was no significant difference in overall survival based on the timing of adjuvant chemotherapy.