Understanding Disparities in Colorectal Cancer Care in California

Despite being one of the most preventable types of cancer, colorectal cancer (CRC) is the second leading cause of cancer deaths in the US, accounting for 9% of cancer deaths. A crucial factor impacting mortality is stage at diagnosis, and screening improves the likelihood of detection at an earlier stage. Due to various socioeconomic factors, however, different racial/ethnic groups get screened at different rates. In particular, Hispanic individuals tend to get screened at much lower rates than both the population at large and their non-Hispanic White (NHW) counterparts. While we may expect lower screening rates to translate into worse CRC outcomes like later stage at diagnosis and higher mortality rates, gross numbers suggest that Hispanic patients do not experience worse outcomes. However, gross numbers may be masking the fact that there are significant demographic differences between Hispanic and NHW individuals like population age structure, income and education levels, and access to medical care, among others.
To better understand the factors that contribute to disparities in screening and whether there are corresponding disparities in outcomes, we conduct our analysis in two steps: we analyze data from the Behavioral Risk Factor Surveillance Survey (BRFSS) and California Cancer Registry (CCR) to examine trends and factors related to screening adherence rates and stage at diagnosis, respectively.
We use BRFSS data to identify factors that explain the screening disparity between Hispanic and NHW individuals in California. We find that this screening gap can be fully explained by differences in observable factors. Specifically, we find that differences in education and income explain the largest portion of the screening gap between Hispanic and NHW individuals. Additionally, we find that having a primary care provider (PCP) and being insured were the most important factors that explained whether someone received screening overall.
We use CCR data to investigate whether Hispanics are more likely to be diagnosed at a late-stage, and if particular factors are associated with late-stage diagnosis. We find that Hispanic patients are slightly less likely to be diagnosed at Stage 1 and slightly more likely to have an unspecified stage of diagnosis compared to NHW patients. The most important factors associated with late-stage diagnosis are area-level poverty and younger age, while rural residence and provider concentration are not associated with late-stage diagnosis.
Given our findings, we suggest increasing knowledge of and adherence to screening recommendations in Hispanic communities, and expanding access to screening in impoverished communities.