Rurality, Race Intersect for Greater Disparities in CRC Outcomes

SAVANNAH, Ga.—Colorectal cancer outcomes tend to be worse for Black Americans than white individuals, and for rural residents than urban dwellers. New research showed a combined disadvantage for Black people living in rural areas.

“The increased understanding of optimal screening and management in colorectal cancer patients has resulted in improved outcomes. Unfortunately, these outcomes are not evenly distributed. Colon cancer mortality in one study was found to be 36% higher in Black men and 34% higher in Black women compared to their white counterparts,” said Edward Tobin, MD, a surgery resident at West Virginia University, Charleston Area Medical Center.

Rural patients have also been shown to have lower survival rates than urban patients, and there’s evidence that this disparity may be worsening, he added.

“The question now is, how do these disparities intersect to affect colon cancer survival?” Dr. Tobin said.

To find an answer, Dr. Tobin and his colleagues used data from the National Cancer Database to conduct a retrospective cohort study of patients with stage II and stage III colorectal cancer diagnosed between 2004 and 2018. They divided the patients into four categories: urban white, urban Black, rural white and rural Black. Next, they performed a univariate Kaplan Meier analysis followed by a univariate analysis.

The study included 448,623 patients (88% white, 12% Black, 83% urban and 17% rural). Survival was highest among white urban patients, with a five-year mortality rate of 31.2% and an overall survival (OS) duration of 47.8 months. “Surprisingly, the rural Black population did not have the lowest survival,” Dr. Tobin said, noting that their five-year mortality rate was 33.3% with an OS of about 47 months. The worst survival outcomes were seen in rural white patients, with a five-year mortality rate of 34.6% and an OS duration of 46.7 months.

But in the multivariate analysis, which controlled for age, sex, comorbidities, insurance status, stage at diagnosis and the type of facility in which patients received treatment, white urban patients again fared best, followed by white rural patients, urban Black patients and rural Black patients.

“The two middle categories are interesting. Urban Black patients do worse than rural white patients, suggesting the disparity by race has a stronger effect than the disparity by rurality,” Dr. Tobin said.

He noted the study’s strengths in being large and comprised of data from a robust source, as well as its weaknesses being retrospective design and limitations in the rigidity of the data.

“We can also talk about clinical versus statistical significance,” Dr. Tobin added. “You may have noticed that the difference in survival between rural Black and urban white patients was less than three months. It may be easy to say that’s not statistically significant, but I challenge anyone to look a colorectal patient in the eye and tell them one or two months doesn’t matter.”

Dr. Tobin presented the study at the 2023 Southeastern Surgical Congress.

Virginia Shaffer, MD, a professor of surgery at Emory University, in Atlanta, who reviewed the paper, had one question: Why had the researchers combined colon cancer and rectal cancer as one cohort? “Most colon cancer patients will go directly to surgery, whereas a large portion of rectal cancer patients receive neoadjuvant therapy. Could that have had an influence on your outcomes?”

Dr. Tobin responded: “That is a good point and something we could look into. I will say that the disparities in race and in rurality separately have been demonstrated consistently across several different cancer types. I would not be surprised if we got similar results after separating colon cancer and rectal cancer, but of course, I can’t say that with any kind of certainty.”