Disparities in Survival Across Multiple Cancer Sites at Low-Income-Serving Hospitals

Social determinants of health play a significant role in the incidence, diagnosis, and treatment of cancers, contributing to healthcare disparities. However, the impact of facility-level factors on patient outcomes are often obscured. We aimed to determine whether hospitals serving the lowest-income patients have poorer overall survival outcomes.

We identified patients diagnosed with nonmetastatic colorectal, breast, gastric, and pancreatic cancers (2010-2019) using the National Cancer Database. Patient median income, estimated by residential zip code, was converted into linear mean scores (LMS), with aggregated scores compiled for each hospital. Hospitals were ranked according to average patient LMS and grouped by quartile, with the lowest quartile representing lowest-income-serving hospitals (LIH) and the top quartile denoting highest-income-serving hospitals (HIH).

A total of 833,874 patients were included for analysis, consisting of patients with colorectal (n = 379,423), breast (n = 389,852), pancreatic (n = 45,543) and gastric (n = 19,056) cancer. The 5-year overall survival (OS) was lower for patients receiving treatment for colorectal (67.6 versus 73.6%, p < 0.001), breast (81.9 versus 89.5%, p < 001), gastric (41.9 versus 56.0%, p < 0.001), and pancreatic (31.5 versus 42.1%, p < 0.001) cancer at LIH versus HIH, and this effect had a dose-dependent relationship with hospital income quartile. Within each hospital quartile, patients with higher income had decreased risk of death compared with those with lower income (p < 0.001).

Patients treated for colorectal, breast, gastric, and pancreatic cancer at LIH have worse survival than those at HIH. Income inequality contributes to differences in healthcare outcomes, and these differences are further compounded by the institution at which a patient receives care.