Medscape Medical News > Features
Carolyn Crist
August 26, 2024
Colonoscopy remains the gold standard method for detecting colorectal cancer (CRC) and removing precancerous polyps.
The recommended age for CRC screening in the United States spans 45-75 years, with the benefits of colonoscopy diminishing considerably after this point.
Older adults are much more likely to experience complications before, during, and after a colonoscopy. Bowel preps can cause dehydration or electrolyte problems in some, while bleeding and bowel perforation can occur perioperatively, and pulmonary or cardiovascular complications may arise postoperatively.
These risks often outweigh the benefits of catching a precancerous lesion or early-stage cancer, especially given the low rates of advanced neoplasia and CRC detected from screening and surveillance after age 75. Yet the research overall suggests that more than half of older individuals continue to receive screening and surveillance colonoscopies outside the recommended screening window.
So is there a point in time when a person is too old to receive a colonoscopy? The answer is not always clear-cut, but life expectancy should be a key consideration.
Michael Rothberg, MD
“Taking the most extreme example, if you have 6 months to live, finding early-stage cancer is not going to help you,” Michael Rothberg, MD, of Medical Institute and director of the Center for Value-Based Care Research, Cleveland Clinic, Cleveland, told Medscape Medical News.
For those with more time, the benefits of continued screening and surveillance may outweigh the risks, but when that balance shifts from helpful to not helpful remains inexact, Rothberg noted.
What’s Recommended?
In May 2021, the US Preventive Services Task Force (USPSTF) lowered the CRC screening threshold to age 45, recommending all adults aged between 45 and 75 years receive screening.
For those aged between 76 and 85 years, the USPSTF upheld its 2016 recommendation of selective screening, noting that the “net benefit of screening all persons in this age group is small” and should be determined on an individual basis. The USPSTF, however, did not provide recommendations on surveillance colonoscopies among those with previously identified polyps.
In November 2023, the American Gastroenterological Association (AGA) issued a clinical practice update that provided advice on risk stratification for CRC screening and post-polypectomy surveillance. For adults older than 75 years specifically, the AGA recommended that the decision to continue CRC screening or perform post-polypectomy surveillance be based on risks, benefits, comorbidities, and screening history and decided on a case-by-case basis.
For instance, previously unscreened patients without comorbidities could benefit from screening beyond age 75 — up to age 80 for men and 90 for women — while those who have had regular colonoscopies, per recommended guidelines, but severe comorbidities that may limit life expectancy could stop sooner, even by age 65.
Although an individualized approach leaves room for variation, it’s essential to consider life expectancy and the time it takes for a polyp to progress to CRC, as well as the risks associated with the procedure itself. Certain older adults are “less likely to live long enough to benefit from surveillance colonoscopy, due to competing, non-CRC mortality risks,” and clinicians should discuss these risks with their patients, the experts explained.
When to Stop Screening Colonoscopies
Research shows that screening colonoscopies continue well after the recommended stop age.
A 2023 JAMA Internal Medicine study found, for instance, that a large proportion of screening colonoscopies occurred among the 7067 patients who were 75 years and older with a life expectancy < 10 years. Overall, 30% of patients aged between 76 and 80 years with a limited life expectancy had a colonoscopy. That percentage increased to 71% for those aged 81-85 years and to 100% for those older than 85 years.
But the benefits of screening were minimal. Overall, colonoscopies detected advanced neoplasia in 5.4% of patients aged 76-80 years, 6.2% of those aged 81-85 years, and 9.5% of those older than 85 years. Only 15 patients (0.2%) had CRC detected via colonoscopy, five of whom underwent cancer treatment. Of those five, four had a life expectancy ≥ 10 years, and one had a life expectancy < 10 years.
At the same time, adverse events requiring hospitalization were common 10 days post-colonoscopy (13.58 per 1000), and the risk for hospitalization increased with age.
“For all kinds of screening, we’re not that comfortable in America with the idea that people are eventually going to die, but as you get older, the potential benefits for screening decrease,” study author Rothberg told Medscape Medical News.
In general, life expectancy provides a good predictor of whether people should continue screening or receive treatment following a CRC diagnosis.
Patients aged 76-80 years in good health, for instance, could benefit from screening and, potentially, treatment, Rothberg said. And “if doctors don’t feel comfortable or confident about predicting life expectancy, taking comorbid illnesses into account can be helpful, especially for that age range.”
Weighing Surveillance Benefits
Surveillance colonoscopy is often recommended post-polypectomy to reduce the risk for CRC. But even in this higher-risk population, those older than 75 years may not benefit.
Recent evidence indicates that those with a history of one or two adenomas less than 1 cm in size have only a slightly (1.3-fold) increased risk for incident CRC — and no significant increased risk for fatal CRC.
Another recent study found that detecting CRC at surveillance colonoscopy was rare among older adults. In surveillance colonoscopies performed among 9601 individuals aged 70-85 years with prior adenomas, 12% had advanced neoplasia detected, and only 0.3% had CRC detected.
Similar rates of advanced polyps (7.8%) or CRC (0.2%) were reported in another recent analysis of more than 9800 adults older than 65 years receiving surveillance colonoscopies.
Despite the low rates of polyp and CRC detection, nearly 90% of patients with recommendation information available received advice to return for a future colonoscopy. Even among patients with no polyps or small ones, almost 60% who had life expectancy of less than 5 years were told to return.
Samir Gupta, MD
Although someone with prior adenomas has a higher risk for CRC, that doesn’t tell the whole story for an individual patient, Samir Gupta, MD, professor of gastroenterology at the University of California San Diego, and co-lead of the Cancer Control Program at Moores Cancer Center, told Medscape Medical News. For older adults, it’s vital to consider the competing risks and how much time it might take for CRC to develop.
At Digestive Disease Week in May, Gupta presented new research that looked at cumulative risk among patients aged 75 years and older with prior precancerous polyps vs prior normal colonoscopies. Although those with prior adenomas had a higher risk for CRC overall, their cumulative CRC risk was low — about 0.3% at 5 years and 0.8% at 10 years. Cumulative CRC deaths were even lower — 0.2% at 5 years and 0.7% at 10 years — while the risk of dying from something other than CRC was 20% at 5 years and 40% at 10 years.
“What this means to me is that patients who are 75 and older should think really carefully about whether they want to do surveillance,” said Gupta, who co-authored the AGA’s clinical practice update. “Someone who is very healthy and doesn’t have obvious medical problems can look at that risk for developing colon cancer and the risk of dying and make a decision about whether there’s enough concern to go ahead with surveillance.”
Those with competing health priorities, on other hand, should likely concentrate on those instead, he said, and feel reassured that even if they choose not to do surveillance, they’re probably not doing themselves any harm.
“The bottom line is that referring older adults or frail adults for surveillance colonoscopy shouldn’t be a rubber stamp or check-the-box action,” Gupta said. “We need to think about it carefully and give ourselves — as clinicians and patients — the room to decide that it may not need to take high priority.”
What to Tell Patients
Overall, older adults who have had prior colonoscopies, no or low-risk polyps, and low CRC risk will likely face greater risks from the procedure than benefits.
“The more invasive the screening the test, the more dangerous it could be,” Rothberg noted.
Audrey Calderwood, MD
Many patients, however, are open to stopping and often trust their primary care provider in the decision-making process, said Audrey Calderwood, MD, director of the Comprehensive Gastroenterology Center at Dartmouth Hitchcock Medical Center. “But the systems we have in place don’t optimally support that decision-making at the time it matters most.”
For example, at a prior colonoscopy, a gastroenterologist may recommend surveillance again in 5-7 years. But in the interim, the patient could have new medications or develop comorbidities and other health issues. Rather than defer to the gastroenterologist’s recommendations from years ago, clinicians and patients can reassess the pros and cons of screening or surveillance based on current circumstances, Calderwood said.
“There should be lines of communication and systems of support to allow primary care providers to decide whether it is still needed,” she said.
While some may be ready to stop, other patients are going to continue to want and ask about CRC screening or surveillance, Rothberg said.
In these instances, communication style matters.
“You don’t want to tell a patient that they’re not going to be screened because they’re not going to live long enough to benefit,” Rothberg said.
However, steering people toward less invasive tests or telling them it’s important to give other health problems priority may be more sensitive ways to communicate that it’s time to ramp down or halt screening.
“Sometimes when you say you’re going to stop cancer screening, older adults misperceive that you’re giving up on them,” Gupta said. “We spend 30-40 years driving home the message that prevention and screening are important, and then it feels like we’re taking it away, so we need to find the best way to discuss it and make the choice that’s comfortable for them.”
Rothberg, Gupta, and Calderwood disclosed no relevant conflicts of interest.
Carolyn Crist is a health and medical journalist who reports on the latest studies for Medscape Medical News, MDedge, and WebMD.
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