Cancer Screening: Better safe than sorry?
Doctors and OHIP often advise that past a certain age, older adults can forgo various screening tests for cancer. But many patients, no matter how old or sick they may be, are reluctant to abandon tests they have been told are life-saving.
For years my advice to women in their seventies has been to stop getting annual mammograms even if they previously had breast cancer. It is highly unlikely that the potential benefit of all this discomfort outweighs the risks of false positives and unnecessary surgery.
I have seen hundreds of people with no known risk for colorectal cancer who continue to get colonoscopies well past the age of established recommendations, that is, well beyond the age of 75. Not to mention the countless men at low risk for prostate cancer who continue to get PSA tests, often at the suggestion of their doctors, when the best evidence says that for such men the test can result in more harm than good.
Few may realize that ill-advised screening tests come at a price and not just the monetary one that ads billions to the cost of health care in this country. Every screening test has a rate of false positive results—misleading indications of a possible cancer that requires usually invasive testing with its own rate of complications; breast cancers that are really not even cancerous growths and biopsies on men’s prostates that show harmless non-aggressive groups of cancerous cells confined in the prostate gland.
A new online survey of randomly selected participants showed that women are more aware of the benefits of mammography screening than its harms. If, for example, a mammogram falsely detects a lesion—a not infrequent occurrence—the false positive result may cause not only serious emotional distress but also lead to a surgical biopsy, which carries its own risks. And by the time they have had ten mammograms nearly half of women will experience a false-positive finding.
Likewise for men with a suspicious rise in the PSA test that results in multiple biopsies of the prostate. And colonoscopy itself can be hazardous, particularly for older people whose intestinal walls have become fragile and susceptible to perforation.
Why do people continue to get tests they don’t need when are health care costs continue to keep rising as the older population keeps increasing its life span?
A primary reason: The widespread belief that it is better to be safe than sorry. Why take a chance that a potentially lethal cancer will go undetected until it is too late for a cure? Doing something is often more appealing than doing nothing. People who think this way consider only the beneficial “what ifs” and not the possible downsides of cancer screening tests.
Another likely reason: It’s free. We live in a great country with a great medical system that covers our health care from cradle to grave. So why not use the system? It covers the cost of annual mammograms, but of course not the accurate digital version which is likely to be more accurate in discriminating between a real lesion and an artifact. The Ontario government has changed about 20 per cent of the machines to digital but how do you know which technology is being used on you when you go for your test. PSA tests are also free after 65 years of age but even the creator of the PSA test has publically asked that it not be used anymore because it is so inaccurate.
In this province, if you are over 50 years of age, you will actually get a letter from the Ontario government suggesting you have a colonoscopy regardless of whether you have any problems or are at risk. And even if the results are negative they will suggest you get one every ten years, and every 2 years if you are at high risk. It is important to know that colonoscopies can actually prevent cancer, not just detect it; if a polyp is found in which cancer could develop, it can be removed during the screening.
Doctors themselves often directly or indirectly encourage ill-advised screening tests. This makes them look like they sincerely care about your health and give them an excuse to schedule more follow-up visits. Although Ontario doctors have insurance, they fear litigation and want to make sure that a cancer did not go undetected and so they would rather order all the tests to protect themselves.
On the other hand, most physicians believe at least as strongly as their patients do in the benefits of screening tests. If you are a woman 55 or older, the Canadian Cancer Society and the Ontario College of Physicians and Surgeons recommend mammogram screening every two years, starting at the age of fifty. But most doctors who endorse screening think it should be done annually, even for women 75 and older.
Although among young and midlife adults the main challenge can be convincing them of the benefits of screening, among people in my age group and beyond, the difficult task more often involves advising patients that it’s time to forgo screening.
“Older adults with limited life expectancy are frequently screened for cancer even though it exposes them to risks of screening with minimal benefits.” A medical team at Johns Hopkins University School of Public Health reported in June in JAMA Internal Medicine.
Rather than being told “you may not live long enough to benefit from this test,” patients are likely to prefer a message like: “This test will not help you live longer. “I feel that it is more honest and is a better reason than age for suggesting an end to screening.