New research suggests surge in incurable prostate cancer from lack of early screening

A surge in the rate of incurable prostate cancer cases could be a sign to rethink Canada’s stance on screening for one of the most common diseases for men, according to new research. 

The new study, published in Current Oncology, looked at decades of prostate cancer cases and deaths. It found rates of late-stage cancers have gone up while mortality rates — which had been dropping for years — have levelled off. 

“Although we couldn’t tell who was screened, the sheer number of cases allows us to draw some conclusions about what happens when you screen or don't screen,” said Dr. Anna Wilkinson, lead author and family physician with the University of Ottawa. 

But some cancer doctors disagree with how the data has been interpreted and maintain that the screening tool — known as a prostate-specific antigen (PSA) test — isn’t accurate and could lead to overdiagnosis and the harms of unnecessary treatment. 

The Canadian task force in charge of prevention has never advocated for prostate cancer screening. 

But in the early 1990s, the U.S. approved the use of the PSA test, which Wilkinson says led to a big uptake here, too. In the early 2010s, the U.S. shifted and both countries were aligned against screening, which allowed researchers to study how case and death rates changed against the backdrops of shifting recommendations. 

“What we actually found is that since recommendations against screening in the U.S.,” Wilkinson said, referring to between 2010 and 2021, “metastatic or stage four prostate cancer has gone up by 50 per cent in men aged 50 to 74, and by about 65 per cent in men in their late 70s.” 

The study also found that mortality rates plunged when screening was more widely supported, and plateaued following the recommendations against it. 

But to Bishal Gyawali, an oncologist and associate professor at Queen’s University in Kingston, Ont., that’s a continuing sign of progress. 

“No matter what [screening] recommendation you are doing, the mortality rates keep falling. So that means this has probably more to do with all the advances in treating prostate cancer that we have achieved over the last few decades.” 

James Dickinson, one of the authors who recommended against the PSA test in Canada, says the data is sound but disagrees with the interpretation. 

He says the higher incidences of late-stage cancer can be attributed to improvements in imaging technology — but also is a byproduct of less screening. 

“If less screening occurs, then less cancer will be found,” said Dickinson, who teaches family medicine at the University of Calgary. “And more will be found when it presents with symptoms, so likely [would] be at later stages, in older men.”

One of the key issues is the PSA screening itself, a blood test which measures a protein that a prostate makes. Too much, and it can be a sign of a problem.