Adjuvant Chemotherapy in Older Patients with Gastric Cancer: A Population-Based Cohort Study

SIMPLE SUMMARY: This real-world population-based cohort study evaluated the efficacy of adjuvant chemotherapy in older patients (aged ≥65 years old) after D2-gastrectomy. Adjuvant chemotherapy was associated with better overall survival and cancer-specific survival than surgery alone. There was no significant difference in survival benefit between those patients who received monotherapy or doublets chemotherapy. ABSTRACT: (1) Background: The effectiveness of adjuvant chemotherapy in older patients with gastric cancer after D2-gastrectomy is unclear. This study investigated the efficacy of adjuvant chemotherapy in elderly patients with stage II/III gastric cancer. (2) Methods: A real-world population-based retrospective cohort of patients aged ≥65 with stage II/III gastric cancer (n = 2616; median age: 73.5; 12.2% aged >80 years) treated between 1 January 1997 and 31 December 2020 were included. All data was retrieved from the Hong Kong Hospital Authority Clinical Management System (CMS). Clinical characteristics of those patients with and without adjuvant chemotherapy treatment were balanced after propensity score matching (PSM). In total, 732 patients treated with adjuvant chemotherapy were matched with 732 patients treated with surgery alone. Hazard ratios (HRs) estimated via Cox proportional hazards regression models were used to compare the overall survival (OS) and cancer-specific survival (CSS) of the two patient groups. (3) Results: Adjuvant chemotherapy was associated with better OS (37 vs. 25 months; HR: 0.80; 95% CI: 0.75–0.84; p < 0.001) than surgery alone. The OS benefit was observed in both the 65–80 (44 vs. 27 months; HR: 0.79; 95% CI: 0.74–0.84; p < 0.001) and >80 (14 vs. 11 months; HR: 0.82; 95% CI: 0.71–0.96; p < 0.001) age groups. A better CSS was observed in patients who received adjuvant chemotherapy than those who only had surgery (5-year CSS: 64.1% vs. 61.1%, HR: 0.85; 95% CI: 0.79–0.93; p < 0.001). (4) Conclusions: adjuvant chemotherapy significantly improved OS and CSS in older patients with stage II/III gastric cancer.