Abstract
BACKGROUND AND AIMS: Postoperative adjuvant chemotherapy in older adults aged ≥ 80 years with locally advanced gastric cancer (LAGC) remains debated owing to concerns over treatment tolerance and limited data. We aimed to assess the effectiveness of postoperative adjuvant chemotherapy in adults aged ≥ 80 years with LAGC using data from the Surveillance, Epidemiology, and End Results database. METHODS AND RESULTS: A total of 2395 patients with LAGC aged ≥ 80 years who underwent radical surgery between 2004 and 2015 were identified. Propensity score matching (1:1) was applied to pair 422 patients receiving adjuvant chemotherapy with 1973 patients who underwent surgery alone. Multivariate logistic regression identified independent predictors of adjuvant chemotherapy, including the period from 2012-2015, pN1-2 and pN3 stages, and radiation therapy. Conversely, age ≥ 85 years predicted decreased chemotherapy use. Cancer-specific survival (CSS) and overall survival (OS) were compared using multivariate Cox analysis, showing significantly longer OS and CSS in the adjuvant chemotherapy group, before and after matching. Subgroup analysis revealed that patients aged 80-84 years and those with N + stages benefited most from adjuvant chemotherapy, whereas patients aged ≥ 90 years did not show significant benefit. CONCLUSION: Postoperative adjuvant chemotherapy should be considered for patients aged ≥ 80 years with LAGC, especially those with lymph node involvement, as it offers significant survival benefits. However, as age approaches 90 years, the benefits of adjuvant chemotherapy may diminish, warranting more cautious application.