Incurable prostate cancer rates have increased nationwide, but prostate-specific antigen tests can find cases at an earlier stage when they are more curable.CHAD HIPOLITO/GM
Anna Wilkinson is a family physician, GP oncologist and an associate professor in the Department of Family Medicine at the University of Ottawa.
Rates of incurable prostate cancer have jumped by about 50 per cent in Canadian men aged 50 to 74, and by 65 per cent in men in their late 70s. Mortality declines, which were dropping rapidly for years, are slowing down despite a multitude of recent treatment advances. Overall, prostate-cancer survival is lower now than it was two decades ago. It might sound unbelievable, but unfortunately this is the current reality of prostate cancer in Canada.
Breast-cancer screening is continuously at the forefront of public discourse. Prostate cancer, beyond Movember, remains firmly in the shadows, with threats of impotence and incontinence muzzling the debate.
A PSA (prostate-specific antigen) test is a blood test that can screen for prostate cancer. It finds cases at an earlier stage when they are more curable, and treatments are less intensive. The PSA is by no means a perfect test – an increased PSA level can be indicative of cancer, but can also be the result of other medical issues, like an enlarged prostate. As well, an elevated PSA result does not always differentiate between slow-growing and aggressive cancers. This can lead to overdiagnosis – finding cancers that you die with, instead of from – as well as overtreatment – medical intervention with limited clinical benefit, but side effects all the same.
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But while the PSA test is imperfect, doing nothing is even less perfect. In the mid-1980s, before there was screening, the only way that prostate cancer was diagnosed was if a man sought medical attention when he developed symptoms, usually bone pain from metastatic disease. Metastatic, or stage IV cancers, are incurable right from diagnosis. Prostate cancer rates during this time climbed continually with age, reaching about 1,000 cases per 100,000 men; more than 600 of those 1,000 men would die from prostate cancer.
Then came prostate cancer screening in the 1990s. Its early use was overexuberant, as even older men with life-limiting medical issues were being screened. Treatment of prostate cancer at that time was a blunt, one-size-fits-all approach, akin to using a sledgehammer for a finishing nail.
Fast forward 30 years: Far from the growing pains of the 1990s, huge strides have been made to mitigate overdiagnosis and overtreatment. Age limits and testing intervals are more clearly defined. The use of MRI prevents one-third of men with an elevated PSA from unnecessary biopsy. Diagnosis and treatment are now uncoupled: Prostate cancers can be managed with “active surveillance,” monitoring the activity and aggressiveness of the cancer and jumping in with treatment only when necessary. Innovations in radiation, surgical and systemic treatments have revolutionized how we treat prostate cancer and lessen the side effects.
But we are still stuck in a rut. The conversation about screening doesn’t even start because we continue to judge the utility of PSA screening based on our outdated, 1990s experience. We are using a yardstick to measure a metre.
A group of colleagues and I recently conducted a study of prostate cancer using Statistics Canada’s Canadian Cancer Registry. We found that when screening was widely used, prostate-cancer rates in men 75 and older actually went down, as more cases were diagnosed in younger men. Mortality rates dropped precipitously for all men, but after U.S. recommendations against screening in 2008, survival peaked and mortality declines lessened despite numerous treatment innovations. At the same time, the number of stage IV cases jumped in men of all ages.
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Although survival for stage IV prostate cancer has increased, the overall survival rate for prostate cancer has not, because the rising number of stage IV cases is overwhelming the benefit of treatment advances. We are running to stand still.
It is clear that despite recommendations against prostate-cancer screening in Canada, a substantial amount of screening activity has been occurring. This status quo means there are no guardrails to ensure that PSA testing happens at the right ages and frequencies. The PSA test requires a primary-care provider to order it, and in many provinces is self-paid. Only those men who are able to self-advocate, who have a provider and who can afford the test can access it. The silence surrounding this issue drives inequity and inappropriate use.
It is time to acknowledge that PSA testing significantly decreases prostate-cancer mortality and incurable disease, and that significant strides have been made to minimize overdiagnosis and overtreatment. PSA screening should not be taken lightly, but neither should the pain, suffering and lives cut short by prostate cancers that could have been cured if diagnosed earlier. Men deserve to have the choice to be screened. It’s time to stop measuring PSA screening with yesterday’s yardstick and start a serious conversation based on the realities of modern screening and treatment. That was then. This is now.