The value of PSA (prostate-specific antigen) screening in prostate cancer is under discussion, with overzealous use potentially leading to overdiagnosis, and a U.S. task force no longer recommending its use. Recent research published in The Journal of Urology suggests that combining drug treatment with the PSA biomarker could raise screening accuracy, particularly in men with hard to diagnose disease whose cancer might otherwise be missed.
Some men have high or fluctuating levels of PSA along with negative prostate cancer biopsies, and may have to undergo the pain, inconvenience (and let's face it, indignity) of repeated biopsies of their prostate to rule in or try to rule out prostate cancer, or find those patients who are likely to have aggressive disease. To try to improve this process, a team from Weill Cornell Medical College gave 276 men from this group daily doses of the 5-alpha-reductase inhibitors finasteride or dutasteride, both of which are designed to reduce the size of an enlarged prostate. In the first phase, in about a third of the men, the researchers measured PSA at 6 and 12 months and biopsied their prostates at 12 months, and in the second phase, in the other two-thirds, they carried out biopsies if PSA levels changed.
In the first phase, the drug therapy reduced PSA levels in all men, but to a greater degree in those with benign rather than malignant disease. In the second phase, around a quarter of the men had a biopsy, and just over half of those showed cancer. Of the cancers, 77% were high-grade tumors.
From the results, the researchers concluded that PSA was a more effective marker in prostate cancer when used with drug therapy, and that they could differentiate prostate cancer from benign prostate disease in patients who are difficult to diagnose, perhaps because biopsies are more effective in smaller prostates. The protocol in the second phase also meant that only those men who didn't need a biopsy did not have one.
"At a time when the value of PSA is being increasingly debated, we have shown that when used in a specific way, it can be of great value in identifying men with previously undetected prostate cancer," says lead investigator Dr. Steven A. Kaplan.
- read the press release
- see the abstract
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