Objective To compare the efficacy of single-agent versus multi-agent adjuvant chemotherapy after radical gastrectomy for elderly patients with stage Ⅲ gastric cancer.

Methods The propensity score matching and retrospective cohort study were conducted. The clinicopatholo-gical data of 456 elderly patients with stage Ⅲ gastric cancer who underwent D₂ radical resection in the Renji Hospital affiliated to Shanghai Jiaotong University School of Medicine from January 2016 to December 2020 were collected. There were 343 males and 113 females, aged 71(range, 65‒89)years. Of the 456 patients, 274 cases undergoing single-agent adjuvant chemotherapy after surgery were divided into single-agent chemotherapy group, 182 cases undergoing double-agent or triple-agent adjuvant chemotherapy after surgery were divided into multi-agent chemotherapy group. Observa-tion indicators: (1) propensity score matching and comparison of general data of patients between the two groups after matching; (2) adverse events during chemotherapy; (3) follow-up. Propensity score matching was done by the 1∶1 ratio, with the caliper value of 0.05. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was conducted using the t test. Measurement data with skewed distribution were represented as M(range). Count data were described as absolute numbers, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Comparison of ordinal data between groups was conducted using the non-parameter rank sum test. The Kaplan-Meier method was used to draw survival curves and calculate survival rates, and the Log-Rank test was used for survival analysis.

Results (1) Propensity score matching and comparison of general data of patients between the two groups after matching. Of 456 patients, 306 cases were successfully matched, including 153 cases in the single-agent chemotherapy group and 153 cases in the multi-agent chemotherapy group. The elimination of age, age-adjusted Charlson comorbidity index, pathological TNM staging confounding bias ensured comparability between the two groups after propensity score matching. (2) Adverse events during chemotherapy. In terms of hematological adverse events, 6 cases in the single-agent chemotherapy group and 16 cases in the multi-agent chemotherapy group had neutropenia, showing a significant difference in the neutropenia (χ²=4.90, P<0.05). In terms of non-hematological adverse events, cases with anorexia and nausea were 77 and 50 for the single-agent chemotherapy group, versus 96 and 69 for the multi-agent chemotherapy group, showing significant differences between the two groups (χ²=4.80, 4.96, P<0.05). (3)Follow-up. All the 306 patients were followed up for 48(range, 8‒61)months. The 5-year overall survival rates of the single-agent chemotherapy group and the multi-agent chemotherapy group were 36.08% and 38.31%, respectively, showing no significant difference between the two groups (hazard ratio=0.93, 95% confidence interval as 0.70‒1.20, P>0.05). Results of further analysis showed that the 5-year overall survival rates were 32.41% and 39.40% for 97 patients of the single-agent chemotherapy group and 97 patients with double-agent regimen of the multi-agent chemotherapy group, respectively, showing no significant difference between them (hazard ratio=1.20, 95% confidence interval as 0.82‒1.70, P>0.05). The 5-year overall survival rates were 43.15% and 37.11% for 56 patients of the single-agent chemotherapy group and 56 patients with triple-agent regimen of the multi-agent chemotherapy group, respectively, showing no significant difference between them (hazard ratio=0.81, 95% confidence interval as 0.65‒1.00, P>0.05).

Conclusions For adjuvant chemotherapy in elderly patients with stage Ⅲ gastric cancer, there is no significant survival advantage of double-agent or triple-agent chemotherapy over single-agent oral chemotherapy. However, there is a higher incidence of neutropenia, anorexia, ausea.