Exploration of optimal time for initiating adjuvant chemotherapy after surgical resection: A retrospective study in Chinese patients with stage IIIA non-small cell lung cancer in a single center

Background: Adjuvant chemotherapy (ACT) can reduce the risk of recurrence and improve survival after surgical resection in non-small cell lung cancer (NSCLC) patients. We explore the optimal time from surgery to initiation of ACT in Chinese patients with stage IIIA NSCLC. Methods: Patients pathologically diagnosed with IIIA NSCLC who underwent radical surgery were included in this study. The cut-off point of time to initiation of adjuvant chemotherapy (TTAC) was determined by maximally selected log-rank statistics. Patients were divided into two groups according to the TTAC cut-off point. Propensity score matching (PSM) was used to eliminate confounding variables, and Kaplan-Meier analysis was used to analyze the impact of TTAC on disease-free survival (DFS). Results: The cut-off time was 46 days from surgery to the first ACT. Prior to PSM, baseline characteristic variables were balanced with no statistical difference between the groups, except for pathologic subtype and smoking history. No difference in DFS was found between the two groups prior to PSM (P = 0.529); after PSM, the median DFS was consistent between the two (P = 0.822). N2 lymph node station involvement was an independent factor associated with poor survival compared with patients with N0 lymph node involvement. Moderate differentiation and postoperative radiotherapy could improve survival; however, TTAC was not significantly correlated with DFS. Subgroup analyses showed no significant correlation between DFS and different TTAC programs. Conclusion: No survival difference was obtained as to when ACT was initiated for patients with stage IIIA NSCLC.