Colorectal cancer survival disparities in persistent poverty areas

We examined whether living in persistent poverty census tracts was associated with disparities in colorectal cancer (CRC) survival and whether the association varied between urban and rural settings.

Using 2013-2019 state-wide cancer registry and 2013-2021 death records data, CRC patients were classified by tract-level persistent poverty and rural/urban status. Overall and CRC-specific survival were compared using Kaplan-Meier estimation and log-rank tests. Adjusted analyses were conducted using Cox proportional hazard and Fine-Gray competing risk models.

During the study period, 558 (53%) of 1055 CRC patients died in persistent poverty tracts versus 3117 (45%) of 6938 patients in nonpersistent poverty tracts. Of the 3675 deaths, 2269 (61.7%) were from CRC-specific causes. In unadjusted analysis, CRC patients in persistent poverty areas had a higher risk of all-cause (HR, 95%CI: 1.28, 1.17-1.40) and CRC-specific (HR, 95% CI: 1.17, 1.04-1.31) mortality. After covariates adjustment, the relationship between persistent poverty and all-cause mortality (HR, 95% CI: 1.17, 1.06-1.29) and non-CRC-specific mortality (HR, 95% CI: 1.34, 1.15-1.57) remained significant, but CRC-specific mortality did not. In subgroup analyses, persistent poverty was associated with increased overall mortality among urban tracts (HR, 95% CI: 1.22, 1.08-1.38), but not rural tracts.

After covariates adjustment, CRC patients in persistent poverty tracts are more likely to die of all causes and non-CRC causes but not CRC-specific causes than those in nonpersistent poverty areas, suggesting that differences in CRC-specific deaths may be partly attributed to demographics, geography, tumor characteristics, and treatment.