More cases of prostate cancer were diagnosed at Stage 4 in recent years compared with about a decade earlier, a development that experts behind a new study suggest could be linked with official recommendations discouraging the use of a hotly debated screening test.<\/p>\n
The prostate-specific antigen test is a simple blood test that can serve as an early warning signal of cancer in men with no symptoms. But the test also has risks: It can lead to overdiagnosis and overtreatment of slow-growing prostate tumours that might never have caused harm had they remained undiscovered. <\/p>\n
For that reason, a national task force in the United States recommended against screening<\/a> with the PSA test in 2012. Two years later, a Canadian task force, which had never endorsed the test for screening, followed suit<\/a>. <\/p>\n The new study<\/a>, published online Saturday in the journal Current Oncology, looks at what happened in Canada before and after the U.S. recommendation changed in 2012. American guidelines often influence how Canadian doctors practise, said Anna Wilkinson, a general-practitioner oncologist at The Ottawa Hospital and lead author of the new study. <\/p>\n One key finding was that rates of prostate cancer discovered at Stage 4, when the disease is metastatic and incurable, increased by about 50 per cent in Canadian men aged 50 to 74 between 2010 and 2021. Late-stage diagnoses rose by about 65 per cent in men 75 and older during the same period. <\/p>\n \u201cI think that we stopped screening and men are presenting, clinically, with advanced disease \u2013 advanced, incurable disease,\u201d Dr. Wilkinson said.<\/p>\n Prostate cancer screening should focus on those with elevated risks, experts say<\/a><\/p>\n She and her co-authors from Statistics Canada, the University of Ottawa and the University of British Columbia analyzed nearly 544,000 prostate cancer cases and nearly 149,000 prostate cancer deaths reported to Statscan between 1984 and 2021. <\/p>\n Along with their findings on late-stage diagnoses, the researchers determined that prostate-cancer mortality decreased in Canada after PSA screening became widely available in the early 1990s, despite no formal recommendation in favour of it. <\/p>\n After the U.S. guidelines changed, however, mortality rates plateaued among Canadian men aged 55 to 69, and fell at a slower pace than before among men over 70. <\/p>\n Prostate cancer treatment options improved significantly during that timeframe, which Dr. Wilkinson said should have led to a steeper decline in mortality rates than what the data show. <\/p>\n However, as James Dickinson, one of the authors of the 2014 Canadian recommendation against PSA screening, pointed out, the new study does not include data on whether or not men took a PSA test before learning they had prostate cancer. <\/p>\n \u201cIt can\u2019t tell us about the effect of screening,\u201d said Dr. Dickinson, a family doctor and adjunct professor at the University of Calgary. <\/p>\n When and how should I be screened for prostate cancer?<\/a><\/p>\n Dr. Dickinson also said by e-mail that the increase in Stage 4 diagnoses could reflect improvements in imaging technology that make it easier to detect the spread of cancer outside the prostate. <\/p>\n \u201cTherefore the numbers have risen, not because there is more Stage 4 cancer, but because we are diagnosing it better,\u201d he wrote. <\/p>\n Scott Morgan, a radiation oncologist at The Ottawa Hospital, and another author of the new paper, said major improvements in diagnostic imaging happened too recently to explain the increase in rates of Stage 4 diagnoses over the course of the study. <\/p>\n The new research was published as Canadians await a revised official recommendation on PSA screening. <\/p>\n In March, former health minister Mark Holland ordered the Canadian Task Force on Preventive Health Care \u2013 the independent panel that crafted the 2014 PSA advice \u2013 to pause its work until an external review could be completed. <\/p>\n Ottawa halts work of task force on cancer screening, other care<\/a><\/p>\n The task force was revisiting its advice on prostate-cancer screening when the halt was called. <\/p>\n