Although the role of adjuvant chemotherapy of resected gastric cancer has been established, many factors including postoperative status, patients' hesitancy or refusal, and hospital process-related delay can make treatment delay to initiate adjuvant chemotherapy. However, whether the delay of treatment impacts on clinical outcome has not been studied yet. The optimal time interval from surgery to adjuvant chemotherapy is not known, either.
Patients who diagnosed of stage II-III gastric adenocarcinoma between 2009 and 2013 in Kyung Hee university hospital were included. We retrospectively collected patients' data such as demographics, TNM stage, types of adjuvant chemotherapy, time interval (TI) between surgery and the first day of adjuvant chemotherapy. Patients were dichotomized based on TI which was predetermined as 3, 4, 5, 6, 7, or 8 weeks. Disease-free survival (DFS) and overall survival (OS) were analyzed according to TI.
One hundred and twenty five patients were identified. All underwent D2 dissection with R0 resection. Median follow-up duration was 30 (3-74) months. The number of patients with stage II and III were 75 (60.0%) and 50 (40.0%), respectively. Types of adjuvant chemotherapy were mainly oxaliplatin plus capecitabine (XELOX) (n = 22, 17.6%), TS-1 (n = 69, 55.2%) and cisplatin plus 5-fluorouracil (FP) (n = 24, 19.2%) with others (n = 10, 8%). Median TI was 4.1 (2.1-9.7) weeks. DFS of patients (n = 45, 36.0%) who started adjuvant chemotherapy within 4 weeks after surgery was significantly better compared to those (n = 80, 64.0%) who initiated after 4 weeks (DFS 4.7 vs 3.7 years, p = 0.019). OS was also significantly discriminated according to TI of 4 weeks (5.2 vs 4.0 years, p = 0.020). Other predetermined TI was not associated with survival outcomes. TNM stage (II vs III) also had significant effect on DFS (4.5 vs 3.1 years, p = 0.020) and OS (4.9 vs 3.4 years, p = 0.028). TI of 4 weeks was also found to be significant in multivariate analysis adjusted for stage (p = 0.038, HR= 0.473 for DFS and p= 0.041, HR 0.44 for OS).
This study suggests that adjuvant chemotherapy for gastric cancer can be initiated at 4 weeks after surgery. Delay more than 4 weeks might be harmful in terms of patients' survival.
Clinical trial identification
All authors have declared no conflicts of interest.