Rates of late-stage prostate cancer increased when screening was reduced, new research finds
A rise in the rate of incurable prostate cancer cases may be a signal to reconsider Canada’s stance on screening for one of the most common diseases for men, according to new research.
new studypublished in current oncologyLooked at decades of prostate cancer cases and deaths. It found that rates of late-stage cancer have increased while death rates – which had been falling for years – have decreased.
“Although we can’t tell who was screened, the sheer number of cases allows us to draw some conclusions about what happens when you get screened or don’t get screened,” Dr. Anna W saidIlkinson, lead author and family physician at the University of Ottawa.
But some cancer doctors disagree with how the data has been interpreted and say the screening tool – known as the prostate-specific antigen (PSA) test – is not accurate and could lead to the harms of overdiagnosis and unnecessary treatment.
Changes in screening
The Canadian task force in charge of prevention has never advocated prostate cancer screening.
But in the early 1990s, the US approved the use of the PSA test, which Wilkinson says led to a big uptake here too. In the early 2010s, the US shifted and both countries united against screening, allowing researchers to study how case and death rates changed against the backdrop of the shifted recommendations.
“We actually found that since the recommendations against screening in the US,” Wilkinson said, referring to between 2010 and 2021, “metastatic or stage four prostate cancer has increased by 50 percent in men aged 50 to 74 and by about 65 percent in men in their late 70s.”
The study also found that death rates declined when screening was more widely supported and stabilized after recommendations against it were lifted.
But for Bishal Gyawali, oncologist and associate professor at Queen’s University in Kingston, Ontario, it’s a continued sign of progress.
“No matter what[screening]recommendations you make, the death rate keeps falling. So what that means is that it’s probably related to all the advances in prostate cancer treatment that we’ve made over the last few decades.”
James Dickinson is one of those writers recommended against PSA testing in Canada says data is accurate but disagrees with interpretation.
He says the higher incidence of late-stage cancer can be attributed to improvements in imaging technology – but it is also a byproduct of less screening.
“If there’s less screening, less cancer will be found,” said Dickinson, who teaches family medicine at the University of Calgary. “More will be found when it manifests with symptoms, so likely (will be) in later stages, in older men.”
Simple but controversial test
One of the major issues is the PSA screening itself, a blood test that measures a protein made by the prostate. Too much, and it could be a sign of a problem.
“The test itself is not that accurate,” said Suping Ling, a cancer care researcher at the London School of Hygiene & Tropical Medicine. “For a screening test, it can identify a lot of false positive cases.”
He and other experts argue that this inaccuracy will potentially lead to more harmful pathways.
“There will be more people who will need to follow up with more accurate diagnostic testing (like) MRI, biopsy, which is invasive,” Ling said. The UK used some of this logic in its draft recommendation Against prostate cancer screening.
Gyawali agrees that the harms of acting on PSA results are real and often not talked about — including surgery that can lead to incontinence or sexual dysfunction. Plus, he says not all cancers have to be removed, so we need a test that can be more specific.
“We need to distinguish between prostate cancer that can kill you… versus prostate cancer that can just happen and grow slowly,” Gyawali said.
Study author Wilkinson agrees but says we have made progress in reducing harm, including the option of doing nothing.
“There has been a shift toward separating diagnosis and treatment,” Wilkinson said.
“Active surveillance is keeping an eye on those low-risk prostate cancers so you don’t get any harm from treatment, but you’re ready to jump in when you need to.”
burden of knowing
Dennis Farbstein, 72, knows both the benefits and risks of screening. His “adventure,” as he calls it, started with a PSA test at age 48 — but it included testing and monitoring for six years.
“I was followed for six years, had a PSA every 18 months, and my numbers went up,” Farbstein recalled. He even had biopsies, one of which left him infected. He eventually had surgery and has been cancer-free for nearly two decades.
“If I hadn’t been tested, it could have gone to other parts of my body, and then I would have been in trouble. So, for me, personally, I was very fortunate,” he said from the Toronto clinic, where he helps newly diagnosed prostate cancer patients.
His case is not unique, but indicative of a culture that Gyawali says is built around screening – where the success of individual cases is used to justify population-level decisions. He says that whether or not something is found from the screening, there is relief and intervention is justified in itself.
“There are a lot of people who have these benign cancers who undergo these procedures, but some of them suffer complications from those procedures for the rest of their lives,” Gyawali said.
“But these people will also always view their screening as something they did right.”
New guidance on all cancer screenings is expected next year after an external review that halted the work of the body in charge of the Canadian Task Force on Preventive Health Care. While prostate cancer guidelines were to be updated, public health officials told CBC News, the pause “Guidelines under developmentWhich also includes prostate cancer screening.
Both Canadian Cancer Society And Canadian Urological Association Advocate PSA screening, but only after discussing the harms and benefits with your doctor.
