An Irish study attempting to get at the root of why men and women delay colon cancer screening found that, despite an uptick in colon cancer cases among younger adults, screening isn’t a priority for some adults while others are under the impression that a healthy diet with regular bowel movements negates the need for regular screening.
The findings are based on a survey of over 2,000 adults who participated in a population-based fecal immunochemical test (FIT) screening program. The authors found that denying the immediacy of the need to be tested and self-exempting from screening because of a belief in a healthy lifestyle were key drivers for opting out of FIT screening.
“What we found was that people who didn’t take part [in the survey] responded much more defensively to the invitation,” said Nicholas Clarke, PhD, a researcher at Dublin City University, who served as the lead author of the study published in the journal Cancer.
The domain of denying immediacy, which covers decisions like putting off a test because of more pressing life events, was associated with a 47% reduction in screening probability. “That’s quite a high percentage. They’re not saying I won’t do it. They’re saying: ‘I’ll wait to get tested for colon cancer until my other health concerns are under control, or until there’s a better test,’ ” he said.
The other suppression category of self-exempting was associated with a 20% reduction in the odds of participation. “They’re saying: ‘I don’t need to be tested because I have enough vegetables in my diet or because I have regular bowel movements,’ ” Dr. Clarke said.
Despite the proven efficacy of screening, many individuals still resist screening. In previous research, Dr. Clarke found that men in Ireland were less likely than women to undergo screening.
FIT works by identifying small amounts of blood in the stool that could suggest the presence of a tumor or precancerous polyps. The test also looks for methylation and DNA mutations that are indicative of precancer polyps or tumors. A positive test calls for a follow-up procedure such as a colonoscopy, where precancerous polyps can be removed to prevent them from developing into tumors.
FIT has similar sensitivity to colonoscopy in detecting cancers (93% vs. 95%), but is less effective with respect to polyps (42% vs. 75%-93%). For average risk adults between 50-75 years old, the U.S Preventive Services Task Force recommends colonoscopy every 10 years; flexible sigmoidoscopy or CT colonography every 5 years, or flexible sigmoidoscopy every 10 years plus fecal immunochemical test (FIT) every year; FIT DNA test every 3 years; guaiac-based fecal occult blood test or FIT test annually.
Findings from the new study
In the new study, researchers contacted both 2,299 responders and nonresponders to FIT tests that had been mailed out as part of a Dublin colorectal cancer screening program between 2008 and 2012. Researchers employed the McQueen defensive information processing (DIP) measure, which includes four domains of defensive attitudes that include information avoidance, mental disengagement or denial, suppression through belief that one is immune, and arguing against the evidence.
In this study, 7,476 men and women in Dublin were invited to participate in a population‐based FIT screening program. In follow-up questionnaires sent to those who did or did not complete FIT, 53% of those who completed FIT screening answered the questionnaire, while 8% of those who did not complete the screening returned the questionnaire. Those who didn’t complete the FIT test had higher DIP scores suggesting more rates of opting out of receiving health information, avoiding doctor visits, prevention avoidance, continually delaying screening, either claiming colon cancer is rare or normalizing cancer risk, and falsely aligning regular bowel movements with good health which was directly associated with less screening.
Increasing rates of early onset colorectal cancer
The research may shed light on reasons for increasing rates of early-onset colorectal cancer. “Often younger people feel invincible and as Beverly Green, MD, MPH, pointed out in an editorial on defensive information processing, invincibility is a good example of self-exemption DIP,” Dr. Clarke said.
“I think what’s underlying these two pieces is a lack of awareness of the trajectory of colorectal cancer, but it’s also the future consequences of not taking part [in screening]. A person can have their colorectal cancer for about 10 years before they begin to feel any symptoms from it, and usually at that point, the disease has gone to an advanced stage, so it’s much more difficult to treat, and the person will have much poorer outcomes. If it’s detected at stage 1, the outcomes are far better,” Dr. Clarke said.
Doctors should react calmly to defensiveness and listen to the patient’s concerns. “Informing them of the aim of screening, i.e. to detect it when its precancerous or at the earliest possible stage, is very important. Letting them know they are taking responsibility for their own health and giving them the best chance of a healthy old age may be a good way of counteracting defensiveness,” he said.
Dr. Green noted that nonresponders claiming lack of immediacy could be swayed with the right approach. She has conducted similar research and subjects themselves suggested the use of marketing techniques “like what happens on Amazon. People remind you frequently the same thing when they get a clue that you have an interest in that behavior. Or, they tell you it’s on sale, and you might lose out from that big bargain if you don’t buy it now. There’s a deadline. I think a lot of the things we might do to nudge people are similar to what’s already happening in marketing,” said Dr. Green, who is a family physician and a researcher at the Kaiser Permanente Washington Health Research Institute.
Dr. Clarke and Dr. Green have no relevant financial disclosures.