Active Surveillance May Miss Aggressive Prostate Cancers in African American Men
A study of more than 1,800 men aged 52 to 62 suggests that African Americans diagnosed with very low-risk prostate cancers are much more likely than white men to actually have aggressive disease that goes unrecognized with current diagnostic approaches. Although prior studies have found it safe to delay treatment and monitor some presumably slow-growing or low-risk prostate cancers, the results of this study indicate that active surveillance does not appear to be a good idea for black men.
The study, the largest analysis of potential race-based health disparities among men diagnosed with a slow-growing, very nonaggressive form of prostate cancer, was reported online in the Journal of Clinical Oncology.
Active Surveillance Not Suitable for All
“This study offers the most conclusive evidence to date that broad application of active surveillance recommendations may not be suitable for African Americans,” said study coauthor Edward M. Schaeffer, MD, PhD, of the Department of Urology at Johns Hopkins University School of Medicine.
“This is critical information because if African American men do have more aggressive cancers, as statistics would suggest, then simply monitoring even small cancers that are very low risk would not be a good idea because aggressive cancers are less likely to be cured,” he said. “We think we are following a small, nonaggressive cancer, but in reality, this study highlights that in black men, these tumors are sometimes more aggressive than previously thought. It turns out that black men have a much higher chance of having a more aggressive tumor developing in a location that is not easily sampled by a standard prostate biopsy.”
Study Details
All study participants, of which 1,473 were white and 256 black, had very low-risk prostate cancer as defined by current National Comprehensive Cancer Network criteria and were thus good candidates for active surveillance. Study participants were selected from a group of 19,142 patients who had undergone radical prostatectomy at Johns Hopkins between 1992 and 2012.
The median age of men in the study was 58, younger than the median ages (62–70) of most men in active surveillance groups. Dr. Schaeffer cautioned that the age difference is a potential “confounder” of the results, highlighting the need for more studies to gauge the safety of active surveillance.
Outcomes
Preoperative characteristics were similar for very low-risk whites and blacks, although black men had slightly worse Charlson comorbidity index scores. Detailed analysis showed that black men had a lower rate of organ-confined cancers (87.9% vs 91%), a higher rate of Gleason score upgrading (27.3% vs 14.4%), and a significantly higher hazard of prostate-specific antigen (PSA)–defined biochemical recurrence of prostate cancer.
The rate of increased pathologic risk, as measured by the Cancer of the Prostate Risk Assessment (CAPRA), was also significantly higher in African Americans (14.8% vs. 6.9%). The 12-point CAPRA score is an accepted predictor of biochemical disease recurrence based on blood levels of PSA, Gleason score, lymph node involvement, extracapsular extension, seminal vesicle invasion, and positive surgical margins.
The data suggest that very low-risk African Americans have different regional distributions of their cancers and appear to also develop more high-grade cancers. Researchers added that these tumors hide in the anterior prostate, a region that is difficult to assess using current biopsy techniques.
Race-specific Surveillance Entry Criteria Needed
Dr. Schaeffer emphasized that “the criteria physicians use to define very low-risk prostate cancer works well in whites—this makes sense, since the studies used to validate the commonly used risk classification systems are largely based on white men.” But, he added, “Among the vast majority of African American males with very low-risk cancer who underwent surgical removal of the prostate, we discovered that they face an entirely different set of risks.”
According to Dr. Schaeffer, the main limitation to the study is that it is a retrospective analysis of the experience of a single academic medical center. “The results of our study do not support the universal rejection of active surveillance in black men,” he noted. “Rather, [they] should promote future studies to address whether alternate race-specific surveillance entry criteria should be used for African American men to ensure oncologic parity with their white counterparts.” The research team at Hopkins is currently developing new strategies to more accurately risk-stratify African Americans with newly diagnosed prostate cancer, he said.
The study was financially supported by the National Institutes of Health’s National Institute of Diabetes and Digestive and Kidney Diseases training Grant No. T32DK007552, the American Urological Association Foundation’s Astellas Rising Star Award, and the Howard Hughes Medical Institute’s Physician-Scientist Early Career Award.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
