Researchers from Poland developed a risk classification model that could reduce the number of individuals who would be classified as high-risk for colorectal cancer after colonoscopy screening.
Paulina Wieszczy, MSc, of the department of gastroenterology, hepatology and clinical oncology at the Centre of Postgraduate Medical Education in Poland, and colleagues wrote that their new model could reduce the burden of surveillance colonoscopies without increasing the risk for CRC in patients with adenomas.
“Increasing demand for surveillance limits the availability of colonoscopy resources for diagnostic and screening purposes,” they wrote. “There is a need to optimize the use of surveillance colonoscopy based on well quantified risk of colorectal cancer and death after adenoma removal.”
Researchers performed a multicenter, population-based cohort study within the Polish National CRC Screening Program comprising 236,089 individuals who underwent screening colonoscopies from 2000 to 2011. During a median of 7.1 years of follow-up, they collected data on development of CRC and CRC deaths. They identified associations between CRC risk and patient and adenoma characteristics — including diameter, growth pattern, grade of dysplasia and number of adenomas — and used those data to build their risk model.
Investigators identified 130 CRC cases in individuals who had adenomas removed at screening (46.5 per 100,000 person-years) compared with 309 cases in individuals without adenomas (22.2 per 100,000 patient-years).
Compared with individuals without adenomas, those with adenomas at least 20 mm in diameter and high-grade dysplasia had an increased risk for CRC (adjusted HR = 9.25; 95% CI, 6.39–13.39).
Risk for CRC was higher than or comparable to the general population only in individuals who had adenomas at least 20 mm in diameter (standardized incidence ratio = 2.07; 95% CI%, 1.4–2.93) or with high-grade dysplasia (SIR = 0.79: 95% CI, 0.39–1.41). Individuals with other adenoma characteristics had lower risk (SIR = 0.35; 95% CI, 0.28–0.44).
While the current high-risk cutoff is at least 3 adenomas or any adenoma with villous growth pattern, high-grade dysplasia or an adenoma at least 10 mm in diameter, Wieszczy and colleagues built their high-risk classification based on an adenoma size of at least 20 mm in diameter or high-grade dysplasia. They wrote that their system would reduce the number of individuals classified as high-risk and requiring surveillance from 15,242 (36.5%) to 3,980 (9.5%). They also said this could be done without increasing risk for CRC in patients with adenomas (risk difference per 100,000 person-years = 5.6; 95% CI, -10.7 to 22).
“To allow policy makers, physicians and individual patients to make an informed choice about surveillance strategies according to resources, values and preferences, we have estimated the absolute risk of colorectal cancer for the different categories of high-risk, and shown how the novel definition of high-risk alter the number of individuals in need of intensive surveillance,” Wieszczy and colleagues wrote. “Optimized use of surveillance may help to shift limited colonoscopy resources to screening and diagnostics.” – by Alex Young
Disclosures: The authors report no relevant financial disclosures.