Guideline recommended gastric cancer care in the elderly: Insights into the applicability of cancer trials to real world

Background: Given the underrepresentation of older persons in cancer trials, the association between increasing age and receipt of recommended gastric cancer care in the United States was examined. Materials and Methods: Using the 1998-2006 SEER database, 8637 Medicare-eligible patients, aged ≤65 years who underwent gastrectomy for nonmetastatic gastric adenocarcinoma were identified. Multivariate analyses was used to assess the effect of increasing age on receipt of recommended gastric cancer care (adequate lymph node evaluation [≤15 lymph nodes] and adjuvant radiation therapy for AJCC Ib-IVM0) and cancer-specific mortality controlling for covariates. Results: While 61% of gastric cancer operations were performed in patients ≤65 years, less than 30% received adequate lymphadenectomy or adjuvant radiation therapy. Older patients were less likely to receive adequate nodal evaluation and adjuvant radiotherapy (P < 0.0001). These findings persisted on multivariate analyses. Older age was also associated with worse cancer-specific mortality. Because an age-tumor location interaction for cancer mortality (P = 0.047) was observed, stratified analyses were performed which showed that the adverse effect of older age on cancer-specific mortality was augmented in proximal gastric cancers. Conclusions: This population-based study showed significant age-based variations in gastric cancer care. These results should encourage assessment of generalizability of gastric cancer trials to this expanding population of elderly in the era of comparative effectiveness research.