 |
May 28, 2002 |
||||||
|
Browse Archives
n Lung n Breast n General n Prostate n Leukemia n Lymphoma n Colon n News/Issues |
Study shows differences in prostate cancer test for Hispanics ORLANDO May 28, 2002 (Cancer Digest) -- In one of the few studies to look at a common blood test for prostate cancer in Hispanics researchers found that different criteria may be needed to interpret the test results for Hispanic men as compared to Caucasians. The prostate-specific antigen (PSA) test, which measures the amount of a protein in the blood produced by prostate cells, is one test used by doctors to diagnose prostate cancer. The new study, however, shows when the test is extended to the point of measuring PSA density (PSAD), it is better able to predict whether a man has malignant or benign disease if the man is a Caucasian than if he is Hispanic. Led by Dr. Erik Goluboff, assistant professor of urology at Columbia University College of Physicians & Surgeons, the researchers presented their data at this week's meeting of the American Urological Association in Orlando, Fla. In their presentation, the researchers said that there is a "cutoff point, in which readings in the PSAD have a 40 percent likelihood of being correlated with confirmed cases of cancer in Caucasian men, but that cutoff point was not useful with Hispanic men. "We don't know what it (the cutoff point) is, but we should probably have a different cutoff point for Hispanic men in interpreting the PSAD, or some other way of managing the Hispanic PSADs," said Goluboff, who is Director of Urology at the Allen Pavilion of NewYork-Presbyterian Hospital. A total of 404 Hispanics and 341 non-Hispanic Caucasians who had "elevated" PSA or abnormal rectal exam underwent transrectal ultrasound and biopsies between 1996 and 2001. (Men were classified as Hispanic if they identified themselves that way, or by their surname.) Prior to biopsy, all patients underwent volume measurements of the entire prostate. Of these patients, 242 Hispanics and 255 Caucasians had a PSA between 2.5 and 10 ng./ml. For these patients, PSAD (that is, PSA as a ratio to the volume of the prostate) was calculated, and the data were broken down between the two ethnic groups and between the negative and positive biopsy groups. The biopsies showed that 35 percent of the Hispanics, and 25.5 percent of the Caucasians, had cancer. When the researchers looked at the PSA there was no difference in the average PSA between Hispanics and Caucasians, or between men with malignant versus benign disease. When it came to PSAD, however, the average for the Hispanics with cancer was 0.194 compared to 0.143 for Caucasians with cancer, a significant difference. Goluboff acknowledges that the 0.143 for the malignant group is below the traditional cutoff point of 0.15. He explains that the cutoff point is "not absolute"-that some cases of cancer will occur below that, and that he biopsies everyone, while some other doctors rely on the cutoff point in trying to avoid unnecessary biopsies. The study is the first to show that at similar levels of PSA, PSAD is higher in Hispanics with prostate cancer than in Caucasians. But in interpreting PSAD readings for Hispanics, it was impossible to tell which would have malignant disease and which would have benign disease. The average for the malignant group was 0.17, and for the benign group 0.12. "Although that might seem to be a big difference, the ranges of the two groups were such that the difference was not statistically significant," Goluboff said. Thus, he concludes that while PSAD is able to predict, with some reliability, between malignant and benign disease in Caucasians, it is not able to do so in Hispanics. Goluboff suggests that a different "cutoff point" for PSAD-rather than the traditional 0.15-may be called for with Hispanic men, or there needs to be some other way of analyzing PSAD in Hispanics. |
||||||
SUBSCRIBE
FREE