Black men diagnosed with low-risk prostate cancer may have more aggressive forms of the disease than nonblack men with the same diagnosis, according to a study published in JAMA.
Thus, even black men classified as having the same Gleason-grade prostate cancer may have a greater risk for death than their white counterparts.
“Data suggest that African American men who have surgery for Gleason 6 cancers are more likely to have more aggressive surgical features than predicted prior to surgery than nonblack men having surgery,” Brandon Mahal, MD, lead researcher from the department of radiation oncology at Dana-Farber Cancer Institute, said in a press release. “The reasons are likely multifactorial ... It could be that Gleason 6 cancer in black men is inherently more aggressive or it may have to do with other nontumor related factors such as how we perform biopsies. Maybe we are undersampling their tumors and missing more aggressive disease, [or] there could be other socioeconomic or access to care factors that drive differences.”
Mahal and colleagues used the SEER and Prostate Active Surveillance/Watchful Waiting databases to analyze 192,224 men (black, n = 31,841; median age, 62 years; nonblack, n = 160,383; median age, 65 years) with localized prostate cancer.
A greater proportion of black patients had clinical T1- to T2a-stage disease (81.3% vs. 75.3%; P < .001) and Gleason 7 to Gleason 10 disease (60.1% vs. 55.8%; P < .001).
Median follow-up was 36 months.
Overall, Gleason 6 disease was associated with a lower risk for prostate cancer death (206 of 83,645; 0.25%) compared with Gleason 7 to Gleason 10 disease (1,481 of 108,579; 0.77%; adjusted HR [aHR] = 0.25; 95% CI, 0.22-0.3).
Also, risk for prostate cancer death overall was not significantly different statistically between black patients (n = 326; 1.02%) and nonblack patients (n = 1,361; 0.85% aHR = 1.1; 95% CI, 0.96-1.25).
However, results showed that 51 of 12,707 (0.4%) black patients with Gleason 6 disease died compared with 155 of 70,938 (0.22%) nonblack patients with Gleason 6 disease (aHR = 1.95; 95% CI, 1.42-2.67), suggesting an increased risk for death among black patients with Gleason 6 disease.
For patients with Gleason 7 to Gleason 10 disease, 275 of 19,134 (1.44%) black patients died of prostate cancer compared with 1,206 of 89,445 (1.35%) nonblack patients (aHR = 1.01; 95% CI, 0.87-1.16), showing comparable risk between the groups.
Researchers found similar results in cohort of 403,022 patients (black, n = 62,736; nonblack, n = 340,286) with prostate cancer with a median follow-up of 65 months. Results in this cohort showed higher 12-year mortality rates among black vs. nonblack patients with Gleason 6 disease (2.2% vs. 1.4%), but comparable rates among those with Gleason 7 to Gleason 10 disease (5.5% vs. 5.3%; P < .001 for interaction).
Limitations of this study included short follow-up periods.
“These data would be an impetus for randomized, prospective trials to both better characterize Gleason 6 disease in black men and to test different management strategies,” Mahal said.
In the U.S., data suggest that an increasing number of men with Gleason 6 prostate cancer are opting for active surveillance, but that option is used less frequently among black men, he added. “That probably is partly because of provider preferences and partly because of patient preferences — both of which are likely impacted by historically observed disparities,” he said. – by John DeRosier
Disclosures : Mahal reports research funding from the Prostate Cancer Foundation. Please see the study for all other authors’ relevant financial disclosures.