More Cons Than Pros Seen with Lowering PSA Cutoff

NEW YORK (Reuters Health) - In screening men for prostate cancer, lowering the threshold for an "abnormal" level of the biomarker PSA from 4 standard units to 2.5 would dramatically increase the number of unnecessary biopsies without reducing the number of prostate cancer deaths, researchers say,

"Millions of men currently have abnormal PSAs (PSA greater than 4) -- many times the number that will develop clinically important prostate cancer," Dr. H. Gilbert Welch noted in comments to Reuters Health. "Some doctors are advocating for a lower threshold to define abnormal (PSA above 2.5). If adopted, this would double the number of men defined as abnormal," he explained.

Welch, of the VA Medical Center in White River Junction, Vermont, and colleagues used survey data to calculate that roughly 1.5 million American men between the ages of 40 to 69 have a PSA level higher than 4.0, justifying a biopsy.

Lowering the threshold to 2.5 would add an additional 1.8 million men to the biopsy list, if all men were screened, the team reports in the Journal of the National Cancer Institute.

This group of men with "abnormal" PSAs would comprise nearly 11 percent of all US men between the ages of 50 and 59 and 17 percent of those between the ages of 60 and 69. However, only 0.3 percent of men in their 50s and only 0.9 percent of men in their 60s are expected to die from prostate cancer in the next 10 years.

"Until there is evidence that screening is effective, increasing the number of men recommended for prostate biopsy -- and the number potentially diagnosed and treated unnecessarily -- would be a mistake," Welch said.

If anything, consideration should be given to raising the PSA cutoff, he and his colleagues contend.

"Because screening always has benefits and harms, it is possible that raising the PSA threshold would enhance the net effect of PSA screening by identifying the people at highest risk of clinically significant disease and thereby limiting the number of healthy people harmed," they write.

SOURCE: Journal of the National Cancer Institute, August 3, 2005.