ORLANDO-In clinical trials, black men with metastatic hormone-refractory prostate cancer have the same and possibly longer survival, compared with whites, according to a pooled analysis of nearly 1,000 patients in four separate randomized phase III Cancer and Leukemia Group B (CALGB) trials.
ORLANDOIn clinical trials, black men with metastatic hormone-refractory prostate cancer have the same and possibly longer survival, compared with whites, according to a pooled analysis of nearly 1,000 patients in four separate randomized phase III Cancer and Leukemia Group B (CALGB) trials.
"The important finding is not the trend toward benefit in African Americans, but the absence of advantage in whites," said Timothy D. Gilligan, MD, a genitourinary oncologist with Dana-Farber Cancer Institute.
It is unclear how far the results can be interpreted, Dr. Gilligan said at the 38th Annual Meeting of the American Society of Clinical Oncology (abstract 725). He added that the data do argue against the disease being inherently more aggressive in black men, at least in this select group of patients.
The finding was unexpected, given the number of studies that suggest black men in the United States have a higher prostate cancer in-cidence, mortality, younger age at diagnosis, and more advanced disease at diagnosis than men who belong to other racial or ethnic groups.
Dr. Gilligan and his colleagues reported on a pooled outcome analysis including 144 black men and 844 whites with hormone-refractory prostate cancer (median age 71, 57% with Gleason sum of 8 or more) enrolled in four different CALGB trials between 1992 and 2000.
The trials evaluated different regimens, including low- vs high-dose megestrol (Megace), antiandrogen withdrawal with or without ketoconazole, hydrocortisone with or without mitoxantrone (Novan-trone), and varying doses of suramin.
Median survival was 15 months for the black patients vs 14 months for whites (P = .425). In addition, the unadjusted hazard ratio for blacks compared with whites was 0.95 (95% CI 0.77-1.12).
In a multivariate analysis, there was a trend toward benefit favoring black patients. Adjusting for a variety of factors (years since diagnosis, baseline PSA, Gleason sum, LDH, alkaline phosphatase, disease measurability, and hemoglobin), blacks had significantly longer survival than whites (hazard ratio .80, P = .033).
Dr. Gilligan hopes the results will help encourage the enrollment of more minorities in clinical trials, so that study results will better apply to the population as a whole. Also, he said, the results suggest that race provides little meaningful prognostic information beyond that obtained from PSA and other established methods. Therefore, researchers need to look at other factors, such as access to care or quality of care, to explain the findings in other studies that survival differences break down along racial lines.
One hope is that researchers will find specific genetic mutations that identify which cancers are high risk and which have more favorable prognostic features. "While, overall, African Americans seem to do worse, race is a very crude marker," Dr. Gilligan said. "We need to figure out the biological, socioeconomic, or cultural issues that underlie the difference in a more scientifically definable way."