In a review of 526,690 patients who underwent radical prostatectomy for localized prostate cancer, researchers from Vanderbilt University Medical Center found Black patients had significantly higher mortality rates compared to other racial and ethnic groups. Asian Americans and Pacific Islanders (AAPIs) had notably lower mortality rates than non-Hispanic whites. Hispanics had slightly lower rates than non-Hispanic whites – despite lower socioeconomic status and significant underinsurance.
The review, published in Cancer, examined clinical and non-clinical factors that might contribute to disparities. “After adjustments for a number of non-clinical factors affecting access to care, the disparity was significantly decreased for Blacks and significantly increased for AAPIs in comparison with non-Hispanic whites,” said first author Wanqing Wen, M.D., a research associate professor of medicine at Vanderbilt.
“We were surprised to find that clinical scores on tumor grade and stage, prior therapy and comorbidities made less of a difference in outcomes,” he said.
Study Reveals Gaps
The researchers used patient records from the National Cancer Database, collected from more than 1,500 centers. Non-Hispanic whites represented 82.1 percent of the study group, Blacks 12.1 percent, Hispanics 4.1 percent and AAPIs 1.7 percent.
The baseline five-year mortality rates were 5.1, 3.8, 3.5 and 3.2 for non-Hispanic whites, Blacks, Hispanics and APPIs, respectively. After adjusting just for age and date of diagnosis, overall mortality rates were 51 percent higher among Blacks, 22 percent lower among AAPIs, and 6 percent lower in Hispanics compared with non-Hispanic whites.
When adjusted for all non-clinical factors, the margin shrank to 27 percent higher for Blacks, while rising to 32 percent for AAPIs. When further adjusted for clinical factors, the margins were 20 percent and 35 percent, respectively. The post-adjustment disparity between Hispanics and non-Hispanic whites was not significantly different.
“Studies of disparities in other diseases have a similar pattern. The same people who have inadequate insurance, lower education and lower earnings are not as likely to have regular annual physicals and screenings as others do,” said Amy Luckenbaugh, M.D., a urologic oncologist and co-author on the study.
This study was the first to leverage a large dataset to show the impact of non-clinical factors – education, median household income and insurance status – on outcomes.
“These are modifiable factors, making this research valuable input for those in policymaking and public education, and for primary care providers who do prostate-specific antigen screenings,” Wen said.
“These are modifiable factors, making this research valuable input for those in policymaking and public education.”
Wen notes that other factors not evaluated in the study, such as smoking, drinking, obesity and physical inactivity, should be investigated for their contribution to the mortality gaps. Additionally, genetic differences among races are likely to affect vulnerability to the disease and outcomes.
In clinic, Luckenbaugh sees a higher number of young Black men than white men with aggressive cancers. “The study supports that Blacks require higher rates of post-prostatectomy radiation and hormone therapies than non-Hispanic whites,” she said.
A Call to Expand Screening
Luckenbaugh envisions a two-fold approach to address non-clinical disparities. “First, we need to promote screening for the appropriate population,” she said. “Second, we need to ensure better access to specialty physicians who take care of prostate cancer.”
This access challenge is a familiar refrain, particularly in rural populations. “We need to know what happens if we make strides in closing the access gap and addressing cultural barriers. Then, we need to factor in the genetic and lifestyle components to create a clearer, more actionable picture,” Luckenbaugh said.
As one example of effective outreach, she notes that a Vanderbilt colleague in urologic oncology, Kelvin Moses, M.D., frequently visits predominantly Black churches to speak on the importance of screening.