Prostate tests find harmless cancers

Almost half of all prostate cancers detected through common screening tests in Australia have been unnecessarily diagnosed.

John Caldwell was diagnosed with prostate cancer aged 49 and is now cancer-free. Picture: Russell Shakespeare

Almost half of all prostate cancers detected through common screening tests in Australia have been unnecessarily diagnosed, putting men through needless worry, treatment and expense.

Research led by Bond University, and published in the journal BMJ Open, found at least 41 per cent of prostate cancers detected through screening in Australia would have remained harmless if left untreated.

In Australia, the lifetime risk of being diagnosed with prostate cancer rose from 6.1 per cent in 1982 to 19.6 per cent in 2012, with a rapid increase following the introduction of prostate-specific antigen testing in 1989.

“The spike strongly suggests we have been overdiagnosing, and by that I mean we are detecting dormant cancers that would never have become symptomatic,” said study co-author Paul Glasziou, director of the university’s Centre for Research in ­Evidence-Based Practice.

“To address this issue of overdiagnosis, all asymptomatic men should engage in an informed discussion with their general practitioner about the risks and potential benefits of prostate ­cancer screening.

“Don’t get me wrong — men still need to remain vigilant when it comes to early detection, however they need to be informed and engage in shared decision-­making with their medical professionals about the harms of prostate cancer screening and other associated procedures.”

The study’s lead author, Than­ya Pathirana, a researcher at CREBP, said overdiagnosis could lead to interventions with risks separate to any cancer.

“What we know about over­diagnosis is it can lead to unnecessary and, in some cases, harmful procedures and treatments such as prostate surgery, radiotherapy and hormone therapy,” Dr Pathirana said.

“In the case of prostate cancer, this can also include a prostat­ectomy (removal of the prostate gland), which can cause incontinence or impotence.”

John Caldwell was diagnosed with prostate cancer in 2009 at the age of 49 through a PSA test. Doctors told him that the non-­aggressive, low-grade cancer was not likely to be a problem for at least 10 years and gave him two options: wait and watch the cancer for any growth, or undergo a prostatectomy as a precaution.

With a wife and two young boys at home, he decided to act early. After a 14-month search for an alternative treatment, Mr Cald­well opted for an isolated form of radiation therapy called brachytherapy and is now ­cancer-free. While agreeing that unnecessarily early diagnosis can affect the mental health of some men, Mr Caldwell reckons it is usually better to know.

“Testing is most important,” he said. “For some, it will be 15 or 20 years before something happens but for some it will be quicker. I think in a majority of cases, (diagnosis) is worth it.”

Katy Bell, another co-author and senior lecturer in clinical epidemiology at the University of Sydney, said the findings would help measure the effectiveness of best-practice initiatives.