PSA tests measure the amount of prostate-specific antigen (PSA) in your blood and are used to check for early signs of prostate cancer. In a recent statement designed to help guide men concerned about the disease, the American College of Physicians (ACP) recommends that doctors should only give PSA tests to men 50-69 years old who show a strong desire to be tested. Even in these patients, the harm of testing will largely outweigh the benefits for most of them.

PSA is a protein produced in the prostate and found mostly in semen. High levels of PSA may indicate the presence of prostate cancer. However, many other conditions, such as an enlarged or inflamed prostate, can also increase PSA levels.

A biopsy involves inserting multiple needles into the prostate and carries its own risks of infection, significant bleeding and hospitalization.

The ACP, the second largest organization of physicians in the U.S., issued a “guidance statement ” recommending against PSA testing in men younger than 50 who are at average risk for the disease, in men older than 69, or in men who have a life expectancy of less than 10 to 15 years. Testing is likely to do more harm than good for these men. The ACP also wants more patient-doctor discussion of the harms and benefits of the test before PSA tests are given.

A substantial percentage of prostate cancers are so tiny and grow so slowly that they cause no symptoms. A PSA test is the first step in detecting those cancers. Yet nearly 90% of men with PSA-detected prostate cancer opt for surgery, radiation treatment or hormone therapy.

These treatments can cause more harm than would leaving the cancer undetected. Up to five in 1,000 men will die within one month of prostate cancer surgery and between 10 and 70 men will suffer life-long adverse effects such as urinary incontinence or erectile dysfunction. This might not have happened if those men had not had a PSA test.

The ACP thinks that fewer patients would expect or want a PSA test if doctors spent time explaining the risks of testing to them. Yet doctors have shown a reluctance to do this in the past, with one survey suggesting that it's easier for physicians to simply continue screening than it is to take the time needed to explain to patients why they should not have a PSA test.

Few patients understand that the PSA test gives many false positives. Or that a biopsy, often the next step after a high PSA reading, is a much less innocuous and more invasive procedure than it may seem. A biopsy involves inserting multiple needles into the prostate and carries its own risks of infection, significant bleeding and hospitalization.

Knowing all this, fewer patients would want or expect a PSA test.

Right now, because doctors may be reluctant to open the discussion, patients may need to do so themselves. The ACP would like that to change.

The guidance statement appears in Annals of Internal Medicine.