CANCER CONUNDRUM
PSA test remains controversial
One typically thinks of men 50 and older getting a PSA blood test to help smoke out prostate cancer.
But B.C. politician Rick Glumac took the test at age 46, a life-changing decision that he encourages others to pursue.
“I noticed some subtle changes that were easy to ignore — and I did for over a year,” says the NDP MLA for Port Moody-Coquitlam. “It started to worry me.”
Turns out he had an elevated PSA score of 4.9. A biopsy confirmed in December that he had prostate cancer, and Dr. Larry Goldenberg performed roboticassisted surgery soon thereafter.
Married with two children, Glumac lost just two weeks of work at the legislature. His prognosis is good.
“It’s been challenging, for sure,” he allows. “I’d never been in the hospital overnight for anything in my entire life. I’ve always been healthy. It was quite a shock.”
Glumac fully supports early detection through the PSA test; it’s not definitive, but an important clue that can help men uncover a potentially deadly cancer early on. He’s a fit man, and had no known family history of prostate cancer. “It’s something I’ll do ongoing to make sure there is no recurrence of this cancer.”
The PSA test measures the amount of prostate-specific antigen, a type of protein, in a man’s blood. When a man has an elevated PSA, it may be caused by prostate cancer, but it could be caused by other conditions such as an enlarged or inflamed prostate.
The trick before undergoing invasive treatment is to determine which cancers are likely to be aggressive and spread, and which are not, instead growing so slowly they are unlikely to pose a threat during a man’s lifetime.
And that’s a big part of the controversy that has raged over PSA testing the past several years.
“The test itself is fairly harmless, a blood test,” explained Ryan Woods, scientific director of the B.C. Cancer Registry. “The concern is if it identifies a whole bunch of cancers that wouldn’t have been diagnosed in someone’s life without that test.
“Those men will get follow-ups for biopsies, some of them aggressive procedures to deal with the tumours. The harm involves additional procedures that might not have been necessary.”
But without the PSA test, men with aggressive cancers might not be diagnosed — at least, not until it’s late in the game.
A troubling chart on Woods’ computer reflects the controversy.
It shows a spike in the rate of prostate cancer diagnosis among B.C. men in the late 1980s through early ’90s. That coincided with the PSA test becoming common, and more men learning that they silently carried the disease.
The troubling part is the sharp decline in detections in recent years, which could be caused by the uncertainty and controversy over the PSA causing fewer family physicians to order the blood test for patients.
And that could mean more men with undetected aggressive cancers.
“We saw a dramatic rise in prostate cancer rates, pretty much consistent in all the developed world, due to a lot more cases being discovered,” Woods said.
The rate of prostate cancer detections was 226 for every 100,000 men in 1993. By 2015, it fell to 103 cases per 100,000, or about the same rate as in 1978.
“Are we now missing some of the ones that really are going to become clinically apparent?” Woods said. “Are we going to catch those ones later on? That’s where we need to monitor data to assess that.”
CHALLENGING THE TEST
In 2014, the Canadian Task Force on Preventive Health Care issued a report recommending against PSA screening for men, although the strength of its recommendations varied by age group: strongest for men under 55 years of age and those 70 years and older; and less so for the 55-69 age group, saying “there is inconsistent evidence of a small potential benefit of screening, and evidence of harms.”
There is a remote risk of death due to a biopsy test, and the potential for infections. Removal of the prostate carries the risk of incontinence and erectile dysfunction.
The task force, which will report back in five years, said its recommendations reflect “concerns with false positive results, unnecessary biopsies, over-diagnosis of prostate cancer, and harms associated with unnecessary treatment.”
Dr. Neil Bell is a professor of family medicine at the University of Alberta in Edmonton. He chaired the team that made the recommendation. The task force mainly involved experts in preventive screening and epidemiology, and concluded that the PSA test had little effect on survivability.
Bell argued in an interview that the “vast majority” of men diagnosed with cancer through the PSA test will not benefit from therapy. “Controversy in prostate cancer screening is going to go on forever, until they get a better test than the PSA test,” he said.
“If you go through all the steps, including surgery, and you’re fine ... your belief system is that it cured you and everyone should have the test.”
The bottom line is that doctors must carefully discuss the implications of treatment with patients before any decision is made.
“There is a concept of shared decision making, which urologists talk about, but I don’t think they actually do it in the manner ... it should be done,” Bell said. “Often, it’s ‘I’ll share my decision with you or figure it out on your own.’”
In the U.S., the medical community has also addressed the issue, but recently made some subtle but important changes. In 2017, draft recommendations of the U.S. Preventive Services Task Force softened its 2012 opposition to PSA screening by suggesting only men 70 and older should not receive such tests.
Within the 55 to 69 age group, it noted the risk of over-treatment has been reduced in recent years by the use of active surveillance in men with low-risk prostate cancer, a way of monitoring prostate cancer that hasn’t spread outside the prostate.
Men whose cancers progress during surveillance are offered surgery or radiation treatment. The U.S. group urges “individualized decision making about screening for prostate cancer after discussion with a clinician.”
QUESTION OF TREATMENT, NOT DIAGNOSIS
Urology surgeons associated with the Vancouver Prostate Centre fully support the PSA test.
“It’s a continuous variable — the higher your PSA, the poorer your outcome,” says executive director Dr. Martin Gleave. “What’s the best way to diagnose prostate cancer? It’s by far PSA. By far. Is there a controversy? Yes, but a lot of that controversy is through misunderstanding.
“The argument was that PSA was catching too many small fish. But across Canada we’ve led the world over the past 20 years in establishing active surveillance as the way to reduce your risk of PSA-detected morbidity.”
Magnetic resonance imaging (MRI) is also used to assess the presence of cancer and the best treatment. Too expensive for general use, the MRI can provide more detailed followup information,
including on whether a cancer has advanced to tissue beyond the prostate. Because of backlogs in the public system, patients may spend $1,000-plus for an MRI in the private system.
At what PSA level should family doctors refer their patients to a urologist?
As a guideline, Gleave says men in their 40s should have a PSA score under 2.5; in their 50s under 3.5; in their 60s under 4.5; and in their 70s under 6.5 — rates that should be followed over time to ensure they don’t increase too quickly. Modest rises over time are considered acceptable.
Dr. Mira Keyes, B.C. Cancer’s head of brachytherapy in Vancouver, said that as a result of the PSA controversy she’s “seeing more patients with more higher-risk prostate cancer, more aggressive disease, requiring multi-disciplinary treatments.”
While the goal is not for every man to receive a PSA test annually, she said that a baseline test before age 50 could be valuable in tracking the disease over time. “It puts the patients into low or high risks of developing prostate cancer.”
Goldenberg fears that the Canadian task force recommendations are robbing men of the chance for early detection and treatment.
“There’s a good expression: Every case of metastatic cancer was once localized curable cancer.”
There is already evidence that the task force recommendations are swaying family doctors.
Goldenberg’s son Mitchell, a urology surgeon in Toronto, headed a 2016 survey, published in the Canadian Urological Association Journal, of 1,254 primary care providers.
The survey found that 54.7 per cent of physicians who were aware of the recommendations reported conducting fewer PSA tests as a result.
Overall, 55.6 per cent of physicians feel that the risks of PSA screening outweigh the benefits.
In B.C., men have to pay about $35 for the PSA test unless the doctor has grounds to request it. The province funded PSA tests for 192,002 men in the 2016-17 fiscal year, which compares with 206,630 men in 2013-14.
Decades ago, Goldenberg would see patients “on crutches with metastasis in their spine or their hips, bone disease, needed their testicles removed — castration — and they would die miserable deaths.
“That’s an uncommon presentation today. Why? Because of PSA screening. The debate should not be on over-diagnoses, it should be on over-treatment. And we’re fixing that.”
Is there a controversy? Yes, but a lot of that controversy is through misunderstanding.