Prostate Cancer Tumors Not More Aggressive In Black Men Than White Men
Black men do not necessarily have more aggressive prostate cancertumors than white men, particularly when tumor characteristics aresimilar and measurements of a certain enzyme are the same, according toa study published in the journal Anticancer Research, Reuters Health reports.
Previousresearch has shown that black men have more aggressive forms of cancerthan white men, but such studies did not include patients with similarcharacteristics and used inconsistent data, lead researcher KhouriSinha of the Veterans Affairs Medical Centerin Minneapolis, Minn., said. For the study, Sinha and colleaguesstudied 25 black and 25 white prostate cancer patients at the VAMedical Center, which provides equal medical care to all veterans.Researchers matched participants by age, tumor grade, clinical tumorstage and blood levels of serum total prostate specific antigen beforethey underwent prostate surgery.
Researchers also measured thelevels of cysteine protease cathepsin B, an enzyme needed for thedevelopment of invasive or aggressive prostate cancer, and stefin A, acathepsin B inhibitor. The ratio of cathepsin B to stefin A indicateshow aggressive tumors might be, according to Sinha. According to thestudy, researchers found that the ratios were similar in tumors ofblack and white men, which means that the tumors were consideredmoderate. Sinha said the results show that the "biological basis ofprostate cancer cell invasion, its progression and development ofaggressiveness is not race-dependent." Thus, the "previous conclusionof race-based differences in prostate cancer requires re-evaluationwith respect to the role of protease enzymes (such as cathepsin B) inthe invasion and spread of cancer cells," Sinha said.
Sinhaalso noted a "highly significant" difference between black and whitemen's use of follow-up care, with white men being four times morelikely than blacks to receive additional treatment. He said, "Mostlikely because of their inadequate follow-up appointments, diagnosis ofrecurrent cancer was delayed in black men who did not receive timelytreatment" (Reuters Health, 10/4).
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