By Marilynn Larkin
NEW YORK (Reuters Health) - 23/9/2019
For patients with adenomas removed during colon cancer screening, surveillance colonoscopy three to five years later provides clinically meaningful benefits and is cost-effective, a U.S. modeling study shows.
"In our model predictions, high-intensity surveillance prevented colon cancer in an additional 1.1% -1.9% of patients with polyps detected at age 50, at limited additional cost," Dr. Reiner G. S. Meester of Erasmus MC University Medical Center in Rotterdam told Reuters Health by email.
Based on U.S. cancer registry data, cost data, and the published literature, Dr. Meester and colleagues created a simulated population of average-risk patients ages 50, 60, and 70 with low-risk adenomas (LRAs; one or two adenomas <10 mm in diameter) or high-risk adenomas (HRAs; three to 10 small adenomas or at least one large one, 10 mm or greater) removed at colonoscopy done for screening or after a positive fecal immunochemical test (FIT).
"Based on the estimates of the benefit, surveillance after three years for high-risk patients and after five years for low-risk patients should at least be considered as an option," not just in the U.S. but also in other countries with similar high colon cancer rates, Dr. Meester said.
As reported online September 23 in Annals of Internal Medicine, without surveillance or screening, lifetime colorectal cancer (CRC) incidence for patients 50 and older was 10.9% after LRA removal and 17.2% after HRA removal.
CRC incidence decreased by 46% to 48% with low-intensity surveillance (10 years after LRA removal and five years after HRA removal); and 55% to 56% with high-intensity surveillance (five years after LRA removal and three years after HRA removal).
Incidences of CRC and surveillance benefits were higher for adenomas detected at FIT screening and lower for older patients.
High-intensity surveillance cost less than $30,000 per quality-adjusted life-year (QALY) gained compared with low-intensity surveillance.
Further, a sensitivity analysis showed that high-intensity surveillance cost less than $100,000 per QALY gained (threshold for cost-effectiveness) in most alternative scenarios for adenoma recurrence, CRC incidence, longevity, quality of life, screening ages, surveillance ages, test performance, disutilities, and cost.
"These findings support U.S. guidelines that recommend surveillance colonoscopy in three years for patients with HRAs and suggest that a five-year surveillance interval may be reasonable in patients with LRAs," the authors conclude.
However, Dr. Meester noted, "There are some important caveats."
"First, the additional benefit of high-intensity surveillance was modest in comparison to the benefit of less intensive strategies versus no follow-up," he said. "Because colonoscopy can be uncomfortable and cause complications, the choice for more versus less intensive strategies should ideally be a shared decision between doctor and patient."
"Second, although clinical follow-up within 10 years is recommended for patients with adenoma, few cancer cases and deaths may be averted during that initial period," he said. "In our model predictions, benefit accumulates later. More clinical studies with long-term outcomes are needed to validate this finding."
Further, he added, "The present study focused on the most common type of precursor polyp, adenomas. We are also planning to look at surveillance for the serrated polyp, a more recently discovered precursor to colon cancer."
The randomized European Polyp Surveillance trial (http://bit.ly/2maaotM), which will compare various surveillance strategies, is currently recruiting patients, he noted.
Dr. Robert Schoen of the University of Pittsburgh, coauthor of a related editorial, commented in an email to Reuters Health, "The value of surveillance colonoscopy for non-advanced adenomas is uncertain. The data are imperfect, so it's hard to construct firm guidelines. This study uses modeling and reports that surveillance is both effective and cost-effective, but a model is only as good as the inputs that go into it, and the inputs when it comes to the value of surveillance are imprecise."
"This paper will not change clinical practice, but it does contribute to the argument that the guidelines should remain flexible, given the uncertainty regarding what is best policy," he concluded.
Ann Intern Med 2019.
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