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High-intensity surveillance in patients whose colorectal adenomas were removed at screening translated to modest lifetime benefits versus low-intensity surveillance -- with acceptable incremental cost-effectiveness, a Dutch-U.S. microsimulation study reported.

Both approaches, however, yielded similar benefits in terms of colorectal cancer (CRC) incidence in the intermediate term.

Without screening or surveillance, base-case analysis of lifetime CRC incidence in a simulated population of 50-year-olds was 10.9% after removal after screening colonoscopy of low-risk adenomas (LRAs) and 17.2% after removal of high-risk adenomas (HRAs), said Reinier G.S. Meester, PhD, of Erasmus MC University Medical Center in Rotterdam, the Netherlands, and colleagues.

With subsequent colonoscopic screening, low-intensity surveillance, or high-intensity surveillance, incidence fell by 39%, 46-48%, and 55-56%, respectively.

"Our results support the current of 3-year surveillance after HRA removal and suggest that 5-year surveillance after LRA removal is reasonable," the investigators wrote in their study online in .

Less intensive strategies, however, may be a better fit in individual care settings, depending on acceptable cost levels, medical resources, and patient preferences, the researchers added.

Other major findings from the study were as follows:

• CRC incidence and surveillance benefits were higher for adenomas detected at fecal immunochemical testing (FIT) screening and lower for older patients

• Compared with low-intensity surveillance, high-intensity surveillance cost less than $30,000 per quality-adjusted life-year (QALY) gained

• In sensitivity analysis, high-intensity surveillance cost less than $100,000 per QALY gained in most of the following scenarios: adenoma recurrence, CRC incidence, longevity, quality of life, screening ages, surveillance ages, test performance, patient disutilities, and cost

Study Details

Using a validated Cancer Intervention and Surveillance Modeling Network, Meester and co-authors modeled U.S. patients ages 50, 60, or 70 with LRAs (one or two small lesions) or HRAs (three to 10 small lesions or one or more large adenomas) removed after colonoscopic or FIT screening.

Surveillance ended at age 80, CRC diagnosis, or death, whichever came first. For comparison, the model also evaluated the following strategies: no further surveillance or screening beyond baseline, and return to routine screening after 10 years with either screening colonoscopy every 10 years or annual FIT screening as recommended for those without prior adenomas in the U.S. and patients with LRAs in Europe.

The study did not simulate sessile serrated polyps because of the lack of high-quality data on prevalence and CRC risk, the researcher explained. Furthermore, in the base-case analysis, the approximately 3% of patients with LRAs harboring villous histology or high-grade dysplasia were not distinguished from other patients with LRAs but were examined in a sensitivity analysis.

Low-intensity surveillance increased colonoscopy use but decreased CRC care costs. Because the lower CRC care costs with a return to screening versus no screening or surveillance more than offset the higher colonoscopy costs, returning to screening became the reference strategy for 50-year-olds, the authors concluded.

The cost-effectiveness ratios of $4,000 per QALY gained for low-intensity surveillance over a return to screening and $18,400 per QALY gained for high- vs low-intensity surveillance were well below the cost effectiveness threshold. However, the team pointed to research suggesting that surveillance may not be cost-effective in LRA patients: A recent , for example, concluded that surveillance may not be cost-effective compared with continued FIT.

In addition, 麻豆传媒 had previously Norwegian findings that adenoma resection without surveillance colonoscopy led to a CRC mortality similar to that of the general population.

Writing in an that accompanied the Annals study, David S. Weinberg, MD, MSc, of Fox Chase Cancer Center in Philadelphia, and Robert E. Schoen, MD, MPH, of the University of Pittsburgh, called the analysis a "well-executed study."

They stressed that despite follow-up surveillance's increased identification of patients with preneoplastic colonic polyps, there is still considerable uncertainty about the usefulness of the approach.

Establishing a firm, evidence-based surveillance policy is challenging, and the frequency of, time required, and the specific factors in the transformation from advanced adenoma to cancer remain poorly understood, Weinberg and Schoen continued. "Therefore, extrapolation of cancer risk and, by extension, surveillance benefit remains inexact."

The editorialists noted that in a recent retrospective , surveillance colonoscopy for advanced adenomas correlated with a 43% reduction in CRC incidence. The benefit of surveillance for LRAs, however, which are four times as common (about 30% vs 7%), is still unknown.

Perhaps these questions will be answered by prospective randomized trials of surveillance colonoscopy intervals now under way in Europe and by the forthcoming FORTE study (Five OR TEn Year Colonoscopy for 1-2 Non-advanced Adenomas), in the U.S., but these trials will take many years to complete, Weinberg and Schoen noted.

Study limitations, Meester, et al. said, included that despite extensive model validation, there is still much uncertainty about CRC development over time across individual patients. In addition, the study model did not distinguish the histologic features of adenomas, nor separately consider sessile serrated polyps. Villous histology and high-grade dysplasia are strongly correlated with large size and higher risk, and excluding these features could have impacted the incidence of CRC and the cost effectiveness of timely surveillance in patients with synchronous serrated polyps, the researchers said.