Growing doubts over standard prostate cancer test

In a commentary in The New York Times, Richard Ablin of the University of Arizona said the screening tool he discovered four decades ago now costs too much and is ineffective.

The American Cancer Society, which does not recommend the prostate specific antigen (PSA) test -- a standard screening for men since the 1990s -- has urged doctors to speak to their patients about its risks and its limits.

Prostate cancer, the second most common cancer in men worldwide after lung cancer, kills an estimated 254,000 men each year.

The new recommendations were based on preliminary results from two major studies -- one led in Europe and the other in the United States -- published last year in the New England Journal of Medicine journal.

The clinical trials found that the blood test could not be proved to save lives.

PSA does not allow to distinguish between aggressive cancers that require intervention and slow-developing tumors that, depending on the patient's age, likely will not be a primary cause of death, according to the American Cancer Society.

Furthermore, the test can also provide erroneous results.

As soon as they turn 50 years old, healthy men who bear no symptoms of cancer and are expected to live at least 10 more years should be informed by their doctors of the pros and cons of a PSA screening before deciding to undergo the test, the cancer society recommends.

"For them, the risks likely outweigh the benefits," it said in a statement.

According to Ablin, American men have a 16 percent chance of being diagnosed with prostate cancer but only a three percent chance of dying from it because most cancers develop slowly over time.

He deplored PSA screenings' annual cost of at least three billion dollars, much of that paid for by Medicare, the insurance program for the elderly, and the Veterans Administration.

"The test's popularity has led to a hugely expensive public health disaster," he wrote in his column.

"As I've been trying to make clear for many years now, PSA testing can't detect prostate cancer and, more important, it can't distinguish between the two types of prostate cancer -- the one that will kill you and the one that won't.

"Instead, the test simply reveals how much of the prostate antigen a man has in his blood," he added.

Levels of PSA, a protein produced only prostate cells, can jump when a prostate tumor grows in size. But they can also increase as the prostate enlarges naturally with a patient's age.

(c) 2010 AFP