By Lisa Rapaport
(Reuters Health) - Black men are more likely to die of prostate cancer than white men in the U.S., but a new study suggests this racial disparity may be largely due to differences in the medical care men receive.
Black men are more likely to be diagnosed with prostate cancer, more apt to have advanced disease at the time of diagnosis, and more than twice as likely to die of the disease than white men in the U.S., researchers note in JAMA Oncology.
African American men are also more prone to chronic illnesses like heart disease and diabetes that diminish their prostate cancer survival odds, and more likely to face financial barriers to care, the authors write.
To better understand what's behind the disparities in mortality, researchers compared outcomes for three groups with the same type of prostate cancer. Most of the men were part of a national registry of 296,273 cancer patients who didn't receive uniform treatment or access to care. Two smaller groups of men did have the same access to care and standardized treatment regimens because they were part of clinical trials (5,854 men) or were receiving care in the Veterans Affairs (VA) health system (3,972 men).
In the two groups receiving equal medical care, black men had the same survival odds as white men, the study found. That suggests the disparate outcomes evident in the larger group result from unequal access to care, the study team concludes.
"Our study showed that when you do not account for any social factors, black men are more likely than white men to die from prostate cancer," said senior author Dr. Daniel Spratt of the University of Michigan in Ann Arbor.
"However, this is likely largely, if not entirely, due to black men having lower socioeconomic status, less insurance, lack of access to quality care, and not receiving standardized guideline concordant care, among many other factors," Spratt said by email. "When you account for equal access to care and standardize treatment, black men do not die more often of prostate cancer."
None of the patients in the study had prostate cancer that had spread beyond surrounding lymph nodes or tissue in the pelvis to other parts of the body.
Most of the men in the study had medium- and high-risk localized prostate tumors that tend to benefit from aggressive treatment like surgery or radiation, rather than the conservative approaches of watchful waiting or hormone therapy often used for men with low-risk tumors.
Among the men in the national cancer registry, black patients were 30 percent more likely to die of prostate cancer than their white counterparts of the same age, the study found.
However, black men in this group were also more likely to be poor and insured by Medicaid, and less likely to receive curative treatment. When researchers adjusted for these kinds of factors, as well as how advanced tumors were at the time of diagnosis, much of the increased death risk disappeared.
Following this adjustment, black men in the cancer registry had an absolute 10-year risk of dying from prostate cancer only 0.5 percent higher than that of white men. This increased mortality risk was concentrated among black men with low- and medium-risk tumors, and wasn't present among black men with high-risk disease.
Among men in the VA and clinical trial groups that had uniform access to care and standardized treatment regimens, researchers found no meaningful difference in prostate cancer mortality rates among patients the same age. In fact, black men in the clinical trial group had a lower 10-year rate of death from prostate cancer than white men.
In all three groups, however, black men had higher rates of death from causes other than prostate cancer than white men.
One limitation of the study is that researchers lacked data to examine any biological differences between black and white men in the risk of developing prostate cancer or of having high-risk or advanced tumors at diagnosis, the study authors note.
"The study does say that a black man of any given stage of disease of prostate cancer should have the same risk of death from prostate cancer as a white man with the same stage and overall health if given proper treatment," said Dr. Otis Brawley of Johns Hopkins University School of Medicine in Baltimore, Maryland, co-author of an accompanying editorial and former chief medical and scientific officer for the American Cancer Society.
"Access to high quality care differs by race in the U.S.," Brawley said by email.
SOURCE: https://bit.ly/2VNQxg8 and https://bit.ly/2XgkV4m JAMA Oncology, online May 23, 2019.