An active controversy among oncologists is centered on when to treat prostate cancer, with some even suggesting that the word “cancer” be removed from the description of low-grade disease to prevent overtreatment. However, a new study shows that these guidelines may not be appropriate for everyone, especially African American men.

“We know that African American men have more aggressive prostate cancer than Caucasian men,” said Kosj Yamoah MD, PhD, chief resident, Department of Radiation Oncology at Thomas Jefferson University in Philadelphia, Pennsylvania. Yamoah’s study demonstrated that African American men with low-grade cancer—which are sometimes watched rather than treated—are more likely to develop aggressive disease sooner than are white men.

Yamoah, together with Timothy Rebbeck, PhD, and colleagues from the University of Pennsylvania, looked at patients whose cancers were low- to intermediate-grade and who underwent surgery to remove all or part of their prostate. The surgery was important because often men are given a biopsy Gleason score of cancer severity based on 12-core biopsy of the prostate gland. This method is imprecise, however, and may not accurately capture men with truly low-risk cancers.

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To bypass this issue, Yamoah and colleagues analyzed only the records of men whose cancers were confirmed to be low-grade via pathologic Gleason scoring after surgical removal. This method looks at several cross-sections of the entire tumor, rather than relying on a spot test. The researchers found that even in these confirmed low-grade cancers, African American men were more likely to have disease progression and worse outcomes than white men. There was an approximately 10% to 15% difference in 7-year disease control in this low-grade group (90% disease control at 7 years for white men versus 79% in African American men).

The study was published in Urologic Oncology (2014; doi:10.1016/j.urolonc.2014.07.005).

Yamoah and colleagues stress that these findings are based on retrospective analysis, which looks at patient records, and that a prospective analysis will be more definitive in helping determine whether African American men with a low Gleeson score should receive more aggressive treatment. In the meantime, Yamoah is investigating the molecular fingerprint that would help identify the African American men at highest risk for disease progression compared with those for whom watchful waiting could still be the best option.