Sophisticated new prostate cancer tests are coming to market that might supplement the unreliable P.S.A. test, potentially saving tens of thousands of men each year from unnecessary biopsies, operations and radiation treatments.

Some of the tests are aimed at reducing the false alarms, and accompanying anxiety, caused by elevated P.S.A. readings. Others, intended for use after a definitive diagnosis, examine the genetic workings of the cancer to distinguish dangerous tumors that need treatment from slow-growing ones that might be left alone.

The tests could provide a way out of the bitter debate over whether healthy men should be screened for prostate cancer.

The problem with the P.S.A. blood test is that many of the cancers it detects are unlikely to cause harm. But there is no reliable way to identify them. So a large majority of men with positive tests undergo surgery or radiation treatment, and many suffer for years, needlessly, from complications like incontinence and erectile dysfunction.