Purpose: Several clinical trials have suggested that adjuvant chemotherapy improves the survival of patients with resected gastric cancer, but the optimal time at which to initiate post-operative adjuvant chemotherapy has not been studied. This study investigated the association between time to adjuvant chemotherapy and survival in gastric cancer.
Methods: We retrospectively identified 266 patients with stage IB-IIIC gastric cancer who received fluorouracil-based adjuvant chemotherapy after radical gastrectomy. Overall survival (OS) was compared between patients grouped according to time from surgery to adjuvant chemotherapy (<45 and ≥45 days). The Cox proportional hazards model was used to analyze the effects of time to initiation of chemotherapy and other clinical covariates on survival.
Results: Of 266 patients, 141 (53%) started adjuvant chemotherapy within 45 days after surgery and 125 (47%) started adjuvant chemotherapy more than 45 days after surgery. The 3-year OS rates were 81.2 and 65.8% for patients starting chemotherapy within 45 days and after 45 days, respectively (p=0.006). Multivariate analysis identified early initiation of adjuvant chemotherapy, completion of the planned chemotherapy, and early-stage disease as favorable prognostic factors in terms of OS (p<0.05). Subgroup analysis suggested that starting chemotherapy within 45 days after surgery was associated with significant OS benefit compared with initiation of chemotherapy after 45 days from surgery in most subgroups.
Conclusions: This retrospective analysis suggests that delaying adjuvant chemotherapy for longer than 45 days after surgery may be associated with poorer survival in patients with resected gastric cancer.