The Effect of Persistent Poverty on Cancer Outcomes in California

Patients diagnosed with cancer in persistent poverty areas (PPAs) are more likely to present with advanced-stage disease and experience decreased survival compared to those in more affluent regions nationally. However, prior studies have not considered the independent effects of PPAs on stage at diagnosis and survival in California, which could inform efforts to improve cancer outcomes.

We identified patients (≥15 years) newly diagnosed with nine cancers (female breast, prostate, lung, colorectal, cutaneous melanoma, oropharyngeal, liver, stomach, and cervical) from 2006 to 2020 in the California Cancer Registry. We used multivariable logistic regression to examine the association between living in PPAs (defined as having a poverty rate ≥20% for approximately 30 continuous years) and late-stage diagnosis (regional/distant versus in situ/localized). We used multivariable Cox proportional hazards regression to evaluate the effect of PPA on overall survival.

Among the 1,706,573 patients in the cohort, 6.0% (101,820) resided in PPAs. More patients in PPAs were younger, non-Hispanic Black or Hispanic, had public or no insurance, and lived in rural areas. Those living in PPAs (versus non-PPAs) had greater odds of late-stage diagnoses for all cancer types (adjusted odds ratios ranged from 1.09 to 1.46, p<0.02), except stomach. Across all cancer types, patients in PPAs had worse survival, even after considering stage at diagnosis and other factors (adjusted hazard ratios ranged from 1.05 to 1.35, p>0.01).

Our findings of worse outcomes for patients living in PPAs highlight the need for more targeted interventions, such as education about cancer screening and funding to support improved access to healthcare in these areas.