Surveillance colonoscopy is cost-effective for patients at high risk for developing colorectal cancer, but aggressive surveillance is costly and less effective for low-risk patients, according to a study published online June 21 in Gastroenterology.
Current guidelines recommend that patients with colon adenomas undergo periodic surveillance colonoscopy. The study sought to determine the cost-effectiveness of these recommendations, explained Sameer Dev Saini, MD, of the Veteran Affairs (VA) Health Services Research and Development Center of Excellence, Center for Clinical Management Research and the University of Michigan Medical School in Ann Arbor, Mich.
Researchers developed a Markov model based on published literature to study various surveillance strategies from the perspective of a long-term payor. The study followed a cohort of 50 year old patients with newly diagnosed adenomas until death. Of the selected cohort, 30 percent were assumed to carry a high risk for the development of colorectal cancer, and the authors measured costs, quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs).
Saini and colleagues determined that performing colonoscopies every three years in high-risk patients and every 10 years in low-risk patients (a 3/10 strategy) was a more costly but also a more effective treatment method than no surveillance. The 3/10 strategy carried an ICER of $5,743 per QALY gained.
The 3/5 strategy of colonoscopy every three years in high-risk patients and every five years in low-risk patients was more costly but marginally more effective than the 3/10 strategy, with an ICER of $296,266 per QALY. This strategy may be reasonable in populations in which a low-risk subgroup cannot be reliably identified or if the miss rate for advanced adenomas is believed to be very high (at least 14 percent), explained the authors, noting that this method resulted in five fewer cancers and one fewer cancer-related death per 1,000 patients entering surveillance.
Finally, a 3/3 strategy (colonoscopy every three years in both high- and low-risk patients) was more costly and less effective than a 3/5 strategy and resulted in two fewer cancers and one fewer cancer-related death per 1,000 patients entering surveillance.
In this method, “results were most sensitive to the annual probability of advanced adenoma formation and the relative risk of advanced adenoma formation in high-risk vs. low-risk patients,” wrote the researchers.
For most clinical circumstances, the study showed that the 3/10 strategy is the optimal strategy, while surveillance colonoscopy is cost-effective for high risk patients.
In the future, improvements in risk stratification for colonic neoplasia could further enhance physicians' ability to target surveillance to those patients most likely to benefit from this practice, researchers concluded.