Prostate screening test does more harm than good: panel

A Canadian panel of advisers is urging doctors to stop administering PSA tests to routinely screen for prostate cancer. This has re-ignited debate on the value of the simple blood test often administered to men in Canada.

“It’s a balance between the very small and uncertain benefits (of PSA testing) against clear and definite harms,” said Dr. James Dickinson, a professor of medicine and member of the Canadian Task Force on Preventive Health Care. The task force is a panel set up by the government to set national guidelines for cancer screening.

ListenMembers of the panel looked at two large studies on the effects of PSA screening on mortality rates. It focused on a European study of more than 162,000 men in seven countries for 13 years.

Routine PSA screening provides ‘small benefit’

It found that of the men who had the PSA test, five out of every thousand died of prostate cancer. Of the men who didn’t get the test, six died out of every thousand died. That difference of one person in a thousand, is a “small benefit” says Dickinson, and it only occurred in men between the ages of 55 and 69 in only two of the seven centres in the trial.

Prostate cancer is very common in Canada. Over half of men over 60 years old have it. But this type of cancer is most often very slow-moving and most men will die of something else before this cancer become dangerous.

The task force found that 40 to 56 per cent of all men diagnosed with cancer are over diagnosed and their cancer would not have caused symptoms or death during their lifetimes.

Science finds harmful risks of routine PSA testing

When people do test positive, that can trigger a “cascade of events,” explains Dickinson, some of which can be harmful. These may include further tests, biopsies, and surgeries which themselves carry risks such as infection, incontinence and impotence. The scientific data suggest that for every man who benefits from PSA testing, 27 are harmed by unnecessary treatment.

Recommendations do ‘a great injustice to men’

The advocacy group Prostate Cancer Canada expressed outrage at the recommendation that doctors stop doing routine PSA tests. President Rocco Rossi called it “a great injustice to men and their loved ones,” in a newpaper opinion piece.

Rossi does not advocate for mass population screening or annual PSA tests but argues if testing is eliminated men who are at high risk for prostate cancer won’t benefit from early detection.

Ultimately, doctors decide

The panel agrees PSA tests are useful when someone is already undergoing treatment for aggressive prostate cancer, but says the science indicates it make no difference to outcomes otherwise.

It is now up to individual doctors in Canada to decide whether to administer the PSA test or not. Some urologists have already expressed their disagreement with the recommendation to not routinely use PSA testing.