Deciding whether to get a given screening test means weighing the potential benefits against the risks
By Wendy Haaf
An array of screening tests and tools is available to help men maintain good health as long as possible and reduce the risk for some serious medical problems. But one size doesn’t fit all, and different organizations sometimes issue conflicting advice about screening. Here’s what men—and their loved ones—need to know.
Screening Versus Investigation
Not all doctor-ordered tests are screening tests—testing to investigate a symptom isn’t screening. “Screening is related to detecting a potential health concern in people who don’t have symptoms,” explains Dr. Rahul Jain, an assistant professor in the Department of Family and Community Medicine at the University of Toronto and a family physician and hospitalist at Sunnybrook Health Sciences Centre.
The aim of screening is to “either prevent something from happening in the first place or find it before it can cause a problem,” says Dr. Henry Yu-Hin Siu, an associate professor in the Department of Family Medicine and Enhanced Skills Care of the Elderly at McMaster University and medical director of the Stonechurch Family Health Centre in Hamilton, Ont.
The catch is that every screening test carries risks as well as benefits. Deciding whether to undergo a specific screening test comes down to balancing the expected benefit against the risks. “The assumption that detecting something earlier will lead to a better outcome is something that has to be proven to me through research before I subject people without symptoms to tests,” says Dr. Roland Grad, an associate professor at McGill University, a family physician with the Herzl Family Practice Centre in Montreal, and a member of the Canadian Task Force on Preventive Health Care (CTFPHC). (The CTFPHC is an independent, arms-length panel of experts that issues national preventive-care recommendations based on the latest evidence.)
Recommended Tests
Blood Pressure
“Blood pressure is one area in which testing will make a huge difference,” Sui says. Most health-care providers now measure it at every patient visit. “High blood pressure may not present with symptoms, and it’s the number one risk factor for stroke and a major risk factor for heart disease,” Jain explains.
Cholesterol and Blood Sugar
Many care providers would agree that it’s worth doing blood tests periodically to check for diabetes and high cholesterol since these are also risk factors for cardiovascular disease. Testing might be “every few years for lower-risk patients and maybe up to every year for people at high risk,” says Dr. Ashraf Sefin, a family physician with the Grandview Family Health Team in Cambridge, Ont., and an assistant professor at McMaster University’s Michael G. DeGroote School of Medicine.
For some people, abnormal results can provide the impetus to take steps towards a heart-healthier lifestyle. Sui, for example, frames the conversation by talking about a patient’s chances of experiencing a heart event over the next 10 years. “If I take 100 people who are exactly like you, how many will have a heart event?” he explains. “And if we change some of those risk factors, you can see how your risk can go from 25 per cent to 20 or 15 or even five per cent.”
Colorectal Cancer (CRC)
This cancer screening is the one with most convincing evidence to support routine use in men between the ages of 50 and 75 who are at average risk. In this age group, Grad says, “clinical trials show benefit.” However, he adds, “what happens after age 75 is an evidence-free zone, because people that age were not included in the studies.” Those who wish to continue screening past 75 should discuss this option with their health-care provider.
Most provinces and territories have organized CRC screening programs using a test that detects hidden blood in stool, which is repeated every two years. (Quebec, Nunavut, and the Northwest Territories are planning or developing a screening program.) Most jurisdictions have switched from an older method, called fecal occult blood testing (FOBT), to a newer type, called a fecal immunochemical test (FIT). If blood is detected, the next step is a colonoscopy—a tiny camera is threaded into the colon to look for growths, called polyps, that can evolve into cancer.
“The FIT is much more accurate than the previous test,” Sefin explains. The FIT has two other advantages over FOBT: it doesn’t require restricting your diet beforehand, and “it requires only one sample, not three samples as in the past,” Sefin adds.
The CTFPHC endorses fecal screening for colorectal cancer as well as a second option for those who don’t mind a more invasive test that typically needs to be repeated only every 10 years. Called a flexible sigmoidoscopy, it’s similar to a colonoscopy but limited to just the lower part of the colon. The CTFPHC currently doesn’t recommend colonoscopy for screening because evidence of benefit is lacking and “it has more harms associated with it” than sigmoidoscopy, Grad says. These include potential bleeding and perforation of the bowel. Clinical trials now under way to probe the value of colonoscopy are expected to report results over the next two or three years.
Weak Recommendation/Potentially Beneficial
Abdominal Aortic Aneurysm
In an abdominal aortic aneurysm (AAA), a section in the wall of the body’s main artery grows weak and balloons. If the stretched out area becomes thin enough, it can rupture. Once this occurs, the chances of survival following emergency repair surgery are roughly 50 to 70 per cent. One of the risk factors for AAA is a history of smoking.
A one-time ultrasound test can detect AAA, providing an opportunity for either monitoring the condition or elective surgery intended to prevent rupture. However, testing also opens up the possibility of over-diagnosis—leading to an operation for an AAA that might never have ruptured.
The CTFPHC has issued a “weak” recommendation for this type of screening in men aged 65 to 80. “This means that the decision regarding doing it versus not doing it is a close call and the patient might reasonably choose not to do it,” Grad explains.
Here’s how the numbers stack up. For every 1,000 men screened, Sui says, “we’re able to prevent two from a potential rupture and at least one death from triple-A.” This is based on a three- to five-year follow-up period. The weak recommendation is based not just on “the [limited] impact on mortality but the complications that can come from a really bad hospitalization,” Sui adds.
For more detailed information, check out the 1,000-Person Screening Tool for AAA on the CTFPHC website: canadiantaskforce.ca.
Lung Cancer Screening
Similarly, the CTFPHC has issued a weak recommendation for one-time low-dose CT screening for lung cancer in people aged 55 to 74 who are either current smokers or quit less than 15 years ago and have an accumulated history of 30 “pack years” (one pack per day for 30 years, or three packs a day for 10 years, for example).
Access to testing depends on where you live—it’s available only in certain locations.
Controversial
Prostate Cancer Screening
Opinions are divided on screening men 55 or older for prostate cancer with a test that measures levels of a substance called prostate-specific antigen (PSA) in the blood. PSA screening is sometimes done in conjunction with a digital rectal exam (DRE)—a health-care provider uses a gloved finger to feel one side of the prostate through the wall of the rectum to check for abnormalities, such as thickening of the tissue. Elevated PSA levels can occur as a result of prostate cancer or, much more commonly, a benign enlargement of the prostate gland that all men experience as they age.
Different organizations hold different positions on PSA screening. Prostate Cancer Canada encourages men to use PSA testing to establish a baseline so that subsequent tests can pick up any unusual changes. The Canada Urological Association recommends that men aged 50 to 70 with a life expectancy of at least 10 years discuss PSA screening with their physician. By contrast, the CTPHC currently recommends against screening with PSA and/or DRE in men aged 55 or older. (An updated guideline is in the works, with a projected release date of 2025.)
Grad, a member of the CTPHC, explains the rationale behind the task force’s position. “When we look at randomized clinical trials of PSA testing for prostate cancer, you see that there are many more men being diagnosed in the screening group, but the difference in deaths due to prostate cancer is almost zero,” he says. (According to the CTFPHC’s tool, of 1,000 men who are screened over 13 years, one will escape death from prostate cancer due to PSA screening.) “I see more harm than good. I see more problems associated with false-positive test results—painful biopsies, bleeding, infection, and complications of surgery.” Then there are men who will undergo “active surveillance” to keep tabs on a tumour that otherwise might not have affected their lives. “That means we’re going to do an MRI every six months and a PSA—so you’ll be in hospital a few times a year doing tests,” Grad says.
Of those 1,000 men who are screened with PSA for 13 years, 720 will have a negative test. Another 178 will have a positive test but no evidence of prostate cancer after further investigation. Among these men, four will experience complications (such as bleeding or infection) serious enough to warrant hospitalization. A further 102 men will be diagnosed with prostate cancer; however, 33 of these cancers would not have caused illness or death. That’s important because treatment carries a risk for complications, as well as side effects such as problems with sexual function. And screening will ultimately have failed to prevent five men from dying of prostate cancer.
Decision aids like the CTFPHC’s 1,000-person tool are helpful because “one of the challenges we have is providing patients with good information that they can understand,” says Dr. Neil Bell, a professor in the Department of Medicine at the University of Alberta and a past member of the CTFPHC who has also written a series of articles on prevention in practice for Canadian Family Physician. “A lot of the ways information is presented to patients exaggerate the benefits of testing.”
In the end, however, whether to test is a matter of individual choice once you’ve weighed both sides of the equation. “That’s where the concept of shared decision-making comes in,” Bell says. “Physicians have to bring an understanding of what the evidence is, and the patient has to bring his values and preferences. You see one man and say ‘Here’s the evidence,’ and he says ‘No, I don’t want that,’ and then you go down the hall and see another person who says ‘I definitely want that.’”
Having such conversations requires something an estimated 6.5 million Canadians currently lack—regular access to a family physician or nurse practitioner. “A good physician/patient relationship is a significant part of making preventive care work in a proper way,” Safin says. “Patients really want to trust their primary-care provider.”
