Benefit for single-agent adjuvant chemotherapy in elderly patients with locally advanced gastric adenocarcinoma

Background: Current NCCN guidelines exclude the possibility of using single-agent adjuvant chemotherapy in locally advanced gastric adenocarcinoma, while allowing doublet chemotherapy. However, single-agent adjuvant chemotherapy is a valid treatment option in other gastrointestinal malignancies, preferred for elderly and/or frail patients. The current study used a nationwide oncology database to assess the benefit of single-agent adjuvant chemotherapy, specifically in the elderly population. Methods: Using the National Cancer Database (2004–2016) we identified 1953 individuals with non-metastatic gastric adenocarcinoma who underwent upfront D2 gastrectomy with pathologic stage ≥ T3 or Npos and free surgical margins, and had not received either preoperative chemotherapy or pre-/postoperative radiotherapy. We used IPTW analysis to compare overall survival between individuals receiving either single- or multi-agent adjuvant chemotherapy, or referred to observation alone. Results: Individuals receiving single-agent chemotherapy had an overall survival benefit compared with observation alone, with an HR of 0.70 (95% CI 0.55–0.88, p < 0.001). Individuals over the age of 65 had an OS benefit with an HR of 0.61 (95% CI 0.46–0.82, p < 0.001). Comparing individuals over the age of 65 receiving single- vs. multi-agent chemotherapy, there was no overall survival difference with an HR of 0.87 (95% CI 0.64–1.18, p = 0.38). Conclusions: Single-agent adjuvant chemotherapy with a fluoropyrimidine in locally advanced gastric adenocarcinoma following D2 gastrectomy can improve overall survival in elderly patients. Clinicians may consider using either capecitabine or 5-FU as a treatment option in the adjuvant setting for this age group.