Timing of Adjuvant Chemotherapy After Surgical Resection for Non-small Cell Lung Cancer: A Target Trial Emulation Using Nationwide Swedish Registry Data.

backgroundWe investigated the impact of time to adjuvant chemotherapy (AC) on survival after surgical resection (<8 weeks or 8-16 weeks) for patients with non-small cell lung cancer (NSCLC) by applying a target-trial emulation. MATERIAL AND

methodsWe used Swedish population-based healthcare registries to emulate a hypothetical target trial, with treatment arms of 'initiate AC <8 weeks postoperatively' and 'initiate AC 8-16 weeks postoperatively'. The clone-censor-weight approach was used in which all patients were cloned and all clones were assigned to each treatment arm. Clones were then censored when the assigned treatment was no longer compatible with the actual treatment.

resultsWe included 510 patients in the hypothetical target trial, of whom 51% received AC and 150 (57%) started AC within 8 weeks. More than half of the patients were female (52.5%) and the mean age was 69 years. The 5-year disease-free survival (DFS) in the emulated trial for the group who initiated AC <8 weeks postoperatively was 50.3% and the 5-year overall survival (OS) was 58.1%. For the group who initiated AC 8-16 weeks postoperatively, the emulated trial showed a 5-year DFS and OS of 49.1% and 57.1%, respectively.

conclusionBy using target trial emulation, our study supports earlier data on timing for AC after surgical resection for NSCLC. However, further research is needed and our data indicate that a randomized controlled trial could be conducted without major harm to the experimental group (>8 weeks).