Science Spotlight

Racial disparities in endoscopy wait-time and stage at diagnosis

From the Issaka Group, Division of Public Health Sciences

Between 2012 and 2016, the colorectal cancer mortality (CRC) in Western Washington was highest in American Indian/ Alaska Natives (AI/AN) and African Americans (AA). AI/AN’s and AA’s mortality rate was 20.7 and 18.7 per 100,000 people, while Non-Hispanic whites was 14.1 per 100,000 people. In other states across the US, the lack of access and other disparity-based factors play a role in the CRC mortality.  Among these, lack of screening is one of the most frequently cited contributors to racial and ethnic CRC mortality disparities. In Washington state, according to the Behavioral Risk Factor Surveillance System, 68% of AA and 66% of AI/AN reported being up to date with CRC screening. Other potential factors could influence the national CRC mortality racial and ethnic disparities. These factors include diagnostic delays, deficient follow-up after symptoms began, and insufficient application of health care services. Furthermore, a lack of follow-up time after the onset of symptoms in CRC racial and ethnic mortality disparities is unknown.

The Issaka group (Public Health Sciences Division) examined retrospectively a cohort of CRC cases from 2011 to 2017. They published their findings a recent publication in the Journal of Racial and Ethnic Disparities. Dr. Rachel Issaka, who led the study stated that the objective was to evaluate whether the lack of diagnostic endoscopy among patients with symptoms factored into racial and ethnic CRC-mortality disparities in the state of Washington. They also sought to determine if CRC stage at time of diagnosis influenced racial mortality disparities. The researchers utilized a retrospective cohort study from 2011 to 2017 to examine CRC cases; the cases were reported by the Washington Cancer Surveillance System (CSS) and the Washington State Cancer Registry (WSCR). In order to identify the incident and first dates of CRC symptoms in association with the endoscopy, the authors used IC9 medical billing codes. The outcome variables included endoscopy completion, median wait-time to endoscopy completion, and stage at diagnosis. 

Graphical Representation of CRC stage at diagnosis
Image from Dr. Rachel Issaka

After exclusions, 2461 patients remained eligible for the study; 84% (n=2909) of patients completed an endoscopy after CRC-associated symptoms were billed. The result displayed no racial and ethnic differences among AA and AN/AI compared to non-Hispanic whites as it relates to CRC stage at diagnosis. Also, there wasn’t a difference in early stage and late stage CRC by race. There was no statistically significant difference in median wait-time (52 days, IQR: 14 – 218) among AA and AI/A.

It’s important to note that AA and AI/AN have reportedly had less access to care, especially in other US states, which has impacted the higher disease CRC mortality. Dr. Issaka elaborated on the results, “Our analysis suggests that other factors including differential access to care, delays in symptom onset to medical evaluation, differences in treatment after diagnosis, and inadequate surveillance after treatment may potentially contribute to observed mortality disparities." Based on the study’s results, it’s uncertain whether the wait time affects patient outcomes; also, this could be due to the slow- growth of CRC. Dr. Issaka summarized, “future projects focusing on these areas as identifying key factors will inform interventions to reduce mortality disparities locally and nationally.”

This research was supported by the National Institutes of Health/National Cancer Institute Cancer Center Support Grant P30 CA015704.

Fred Hutch/UW Cancer Consortium member: Rachel Issaka, John Inadomi, and Scott Ramsey

Issaka RB, Li L, Fedorenko C, Ko CW, Inadomi JM, Ramsey SD. Racial Disparities in Colorectal Cancer Mortality: the Role of Endoscopy Wait-Time and Stage at Diagnosis. Journal of Racial and Ethnic Health Disparities. 2020 Feb 12:1-8. DOI:10.1007/s40615-020-00721-x

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