The Persistence of Poverty and its Impact on Cancer Diagnosis, Treatment and Survival

Objective: To determine the effect of persistent poverty on the diagnosis, surgical resection and survival of patients with non-small cell lung (NSCLC), breast, and colorectal cancer.

Background: Disparities in cancer outcomes exist in counties with high levels of poverty, defined as ≥20% of residents below the federal poverty level. Despite this well-established association, little is known about how the duration of poverty impacts cancer care and outcomes. One measure of poverty duration is that of "persistent poverty," defined as counties in high poverty since 1980.

Methods: In this retrospective cohort study, patients with NSCLC, breast and colorectal cancer were identified from SEER (2012-2016). County-level poverty was obtained from the American Community Survey (1980-2015). Outcomes included advanced stage at diagnosis (stage III-IV), resection of localized disease (stage I-II) and cancer-specific survival. Hierarchical generalized linear models and accelerated failure time models with Weibull distribution were used, adjusted for patient-level covariates and region.

Results: Overall, 522,514 patients were identified, of which 5.1% were in persistent poverty. Patients in persistent poverty were more likely to present with advanced disease [NSCLC odds ratio (OR): 1.12, 95% confidence interval (CI): 1.06-1.18; breast OR: 1.09, 95% CI: 1.02-1.17; colorectal OR: 1.00, 95% CI: 0.94-1.06], less likely to undergo surgery (NSCLC OR: 0.81, 95% CI: 0.73-0.90; breast OR: 0.82, 95% CI: 0.72-0.94; colorectal OR: 0.84, 95% CI: 0.70-1.00) and had increased cancer-specific mortality (NSCLC HR: 1.09, 95% CI: 1.06-1.13; breast HR: 1.18, 95% CI: 1.05-1.32; colorectal HR: 1.09, 95% CI: 1.03-1.17) as compared with those without poverty. These differences were observed to a lesser magnitude in counties with current, but not persistent, poverty and disappeared in counties no longer in poverty.

Conclusions: The duration of poverty has a direct impact on cancer-specific outcomes, with the greatest effect seen in persistent poverty and resolution of disparities when a county is no longer in poverty. Policy focused on directing resources to communities in persistent poverty may represent a possible strategy to reduce disparities in cancer care and outcomes.