Association of facility type and metastatic burden with survival in gastric adenocarcinoma: A National Cancer Database study.

Abstract

11065 Background: While we know metastatic burden dictates survival in gastric adenocarcinoma (GA), how this intersects with where a patient receives care remains less clear. Academic centers (AC) often report better outcomes, but we haven't fully determined if this "academic advantage" holds true once you account for the sheer extent of disease at the time of diagnosis. We set out to test whether AC care offers a survival benefit that persists regardless of a patient's baseline metastatic burden. Methods: We retrospectively analyzed the National Cancer Database (2016–2023), identifying 102,869 patients with GA. We grouped patients by facility type (AC vs. community). We mapped metastatic burden at diagnosis across six specific sites: bone, brain, liver, lung, distant lymph nodes, and other. After comparing baseline characteristics, we estimated 3-year overall survival (OS) using Kaplan–Meier methods. Our primary tool was a multivariable Cox model, adjusting for age, Charlson–Deyo score, clinical stage, and metastatic burden to isolate the link between facility type and mortality. Results: Of the 102,869 patients, 58.4% (n = 60,064) were treated at ACs and 41.6% (n = 42,805) at community sites. Interestingly, community patients arrived with a higher burden of disease (33.8% vs. 30.4%; p < 0.001), and 11.7% of the total cohort had multi-site metastasis (≥2 sites). The liver was the most frequent site of spread, appearing more often in community settings (18.4% vs 15.4%; p < 0.001). Three-year OS was significantly higher at ACs (45.2% vs 35.8%; p < 0.001). After adjusting for site count, comorbidity, age, and stage, AC treatment remained independently associated with lower mortality (HR 0.81; 95% CI 0.80–0.83; p < 0.001). Notably, this academic survival advantage was not driven by any single metastatic site; the benefit persisted across all individual sites of involvement, including brain and lung, with no site showing a loss of AC advantage. Conclusions: Survival differed by treatment facility even after accounting for metastatic burden. Patients treated at academic centers had better outcomes across metastatic sites, including those with extensive disease. These findings point to differences in care delivery and access to specialized expertise. Expanding academic practices, such as multidisciplinary tumor boards and referral pathways, into community settings may help reduce these gaps.