Benefits of cancer tests in dispute

Questions raised: Breast screening. Picture: Natalie Slade/The Kalgoorlie Miner

An Australian public health expert has made a controversial warning about the downside of breast cancer screening, saying it is up to five times more likely to result in a false alarm for a woman than save her life.

Alexandra Barratt from Sydney University's School of Public Health believes the potential harms from prostate cancer screening are even greater, with a man up to 50 times more likely to have cancer over- diagnosed than to have his life saved from a PSA blood test.

The comments come ahead of her public talk in Perth today at the invitation of the Cancer Council of WA, which supports established programs screening for breast, cervical and bowel cancers.

The council maintains it is important people understand the downside of screening, which can include false positive test results or having a relatively harmless abnormality treated aggressively.

Professor Barratt said screening helped in early detection but it should not be viewed as a silver magic bullet.

An over-diagnosed cancer was a harmless cancer detected by screening, which otherwise would never have been found and the person would have died from something else.

"In those cases there is no benefit - there is only the harm of undergoing cancer treatment and the risk of experiencing side effects that go with it," she said.

"What we do know is that your chance of having an over-diagnosed cancer is greater than having your life saved by screening.

"In the case of breast cancer screening, we think it's three to five times greater and with prostate cancer the risk is estimated to be 10-50 times greater than having your life saved."

Cancer Council WA director of education and research Terry Slevin said it was important people responded to reminders about screening and discussed them with their doctor.

"We appreciate that some people may think this is sending mixed messages but what we are doing is trying to move towards a more sophisticated understanding of cancer screening," he said.

Professor Barratt's free talk is at 12.30pm in the State Library Theatre at Alexander Library in Francis Street.