Prostate cancer screening: It’s time for advocates to put up or shut up
In 2014, the Canadian Task Force on Preventive Health Care (of which I was a member) published its recommendations against screening for prostate cancer, saying that there was inconsistent evidence for a small benefit, but clear evidence that many men would be harmed by the follow-up of a false positive test.
Prostate Cancer Canada, an organization that advocates for screening and care of men with prostate cancer, responded vigorously to the recommendations, asserting that, “Quite simply, these guidelines do not only a great disservice but also a great injustice to men and their loved ones.” PCC recommends that men be screened from the age of 40 or even earlier. They use gimmicks such the Famous Fingers campaign, Movember, “Wear Plaid for Dad,” and Prostate Cancer Awareness Month, coming in September, to encourage fundraising and keep prostate screening in the public eye.
These efforts have wide reach. Articles in print and TV interviews feature prominent men who have had the test, followed by surgery or other treatments, and believe they have been cured. These include former B.C. judge and politician Wally Oppal, wrestler Bret Hart, former Dragons Den star Brett Wilson, and CFLer Damon Allen. Prostate Cancer Canada asserts that one in seven Canadian men will be diagnosed with prostate cancer, not mentioning that if men are not screened, the diagnosis rate is less than half that. Interviews with urologists depict them as skilled surgeons saving men’s lives, and downplay the risk that no matter how good the surgeon, men may develop post-operative complications and even die. They discuss loss of sexual function and incontinence, but minimize these. They avoid mentioning the high proportion of men whose cancer recurs despite treatment. They do not warn that most of the men who would have died from disseminated prostate cancer without screening still die, since the effectiveness of screening is small.
The PCC has offered misleading assertions such as, “With early detection, survival is close to 100 percent.” Yes, because most of these men have a cancer that would never kill them, nor even be diagnosed if they were not tested. Or, “It’s a simple blood test.” It is, but given its inaccuracy, many men then go through a diagnostic and treatment process that is anything but simple. The first step is multiple-needle biopsies that take samples from their prostate (which entails risk of infection). Biopsies must be interpreted by a pathologist, a difficult and often uncertain process for early disease. Imaging measures the extent of disease. Then men have to choose between treatment options. These include close observation with repeat testing to see if the disease is progressing, major surgery, radiotherapy by implants or external beam, and chemotherapy of various types.
Stuart Edmonds, vice-president of research, health promotion and survivorship at PCC, says that because men with low-risk cancer are now not initially treated but undergo regular surveillance, the harm is much reduced. But it appears that within a few years of being diagnosed with low-risk prostate cancer, many men or their physicians become anxious about regular repeat testing and opt for surgery. Once men have had the initial positive test, they are on a roller coaster, out of control, with no way to get off.
Edmonds also says that by screening and treating early, the health care system would spend less money treating men with advanced cancers. This is possible, but with the PSA screening approach, the system spends much more treating men with cancers that would never advance at all if left alone. And they spend money on care for long-term complications and side effects, since these treatments cause incontinence of urine in some and impotence in many. Radiotherapy can cause severe malaise for a long period, rectal inflammation with bloody diarrhea, and in the long term, tissue fibrosis. Hormone-deprivation therapy causes men to have menopause-like symptoms, while chemotherapy may cause nausea, vomiting, and infection.
The Canadian Urology Association recommends screening for men age 45 to 69. However, it recognizes the fine balance between small benefits and substantial harms, and it recommends that men make a fully informed decision before screening, but neither they nor PCC has specified their estimate of the probability of benefit and how to balance this benefit against the possibility for harm.
The Canadian Task Force has made these calculations, and summarizes them in the form of decision aids. The pro-screening organizations disagree with the Task Force but conspicuously avoid justifying their position by not providing their interpretation of the research on the outcomes of screening. While they suggest that men should talk to their doctors, neither Prostate Cancer Canada nor the Canadian Urology Association provides any decision aids for doctors to help men fully understand their choices. Given the massive difference in invasive cancer rates between men in their 40s and those in their 60s, probability figures need to be presented for each age group. Since PCC advises that high-risk men (those with family history of prostate cancer and Black men) should be screened even earlier, they should also provide evidence as to how they estimate the outcome for these groups.
It is time for the leaders of Prostate Cancer Canada and the Canadian Urology Association to put up or shut up: Tell us what they think the outcomes are when men are screened. What proportion of men in each age group will be found positive, will be advised to have further investigation including prostate biopsy, and will proceed to operations or other treatments? What proportion will have complications, how many will have their lives saved, and how many will still die of metastatic prostate cancer? Men deserve that information. Otherwise, having the test and following its consequences is like buying an old car from an advertisement without inspection or road report, and not even knowing the price until after taking delivery.
And while they are at it, perhaps Prostate Cancer Canada will also inform us how much funding they get from companies that profit by selling tests, medical devices for use in operations, drugs for treatment of this disease, and diapers to collect incontinent urine. Their meetings and annual reports feature the logos of these beneficent companies, but not how much they contribute, whether directly or indirectly. The public should know how the money from these donors has been leveraged, and the people who fundraise for PCC should know how much their contributions assist the marketing and profits of those companies.
James Dickinson is a professor of Family Medicine and Community Health Sciences at the University of Calgary. He was a member of the Canadian Task Force on Preventive Health Care, and a co-author of their guidelines on prostate screening. As the owner of a prostate gland, the issue of what to do about prostate cancer is personal!