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Surveillance colonoscopy linked to lower CRC incidence in at-risk patients
Follow-up surveillance colonoscopy after resection of intermediate-risk adenomas was associated with a reduced incidence of colorectal cancer in the U.K., according to research published in the Lancet Oncology.
However, the value of surveillance colonoscopy for low-risk patients remains unclear, investigators concluded.
“The findings could influence national and international guidelines for the screening and surveillance of bowel cancer and could lead to cost savings for the NHS by reducing unnecessary procedures,” Wendy Atkin, PhD, from the department of surgery and cancer at Imperial College London, said in a press release. “Colonoscopies carry a small risk of complications for patients, and are demanding on NHS resources, with around 20% of colonoscopies in the U.K. performed for surveillance. It is therefore important to assess whether all people classed as being at intermediate risk need to undergo follow-up colonoscopy.”
Atkin and colleagues performed a retrospective cohort study of 11,944 patients (median age, 66.7 years; 55% men) who had intermediate-risk adenomas (high-risk, according to U.S. criteria) resected at 17 hospitals in the U.K. from 1990 through 2010, and who were then offered surveillance colonoscopy every 3 years. These patients were then followed up through 2014 (median follow-up, 7.9 years).
The investigators stratified these patients into lower- and higher-risk subgroups based on polyp and procedural factors, and then evaluated the effect of surveillance on CRC incidence.
Colorectal cancer occurred in 210 patients, and CRC incidence at 10 years was 3.3% in higher-risk patients vs. 1.1% in lower-risk patients. Overall, 42% of patients did not undergo surveillance colonoscopy, while 58% underwent at least one.
Atkin and colleagues found an association between undergoing one (adjusted HR = 0.57; 95% CI, 0.4-0.8) or two surveillance colonoscopies (aHR = 0.51; 95% CI, 0.31-0.84) and a significantly lower incidence of CRC compared with no surveillance.
Further, 74% of patients had a suboptimal quality colonoscopy, proximal polyps, a high-grade adenoma or a large adenoma exceeding 20 mm at baseline; researchers deemed these patients higher-risk. Among them, patients who did not undergo surveillance colonoscopy showed a significantly higher CRC incidence compared with the general population (standardized incidence ratio [SIR] = 1.3; 95% CI, 1.06-1.57). Conversely, CRC incidence was lower compared with the general population in lower risk patients who lacked these characteristics (SIR = 0.51; 95% CI, 0.29-0.84).
“The quality of colonoscopy has improved in recent years and it is important we identify those people who would benefit from a follow-up colonoscopy,” Atkin said in the press release. “This research showed that there is a subgroup that definitely benefits but there is also a subgroup that possibly don’t require a follow-up colonoscopy. The results of this study provide robust evidence which will be important for informing future surveillance guidelines for how we monitor people in the intermediate-risk group, and will help minimize the costs and risks associated with the unnecessary colonoscopies that are currently performed.”
Prospective studies are needed to validate this evidence, because although the study is “excellent,” it is limited by its retrospective design, according to a related editorial by Sidney J. Winawer, MD, and Ann G. Zauber, PhD, both of the Memorial Sloan Kettering Cancer Center in New York. Such prospective studies can help to inform guideline modifications by further examining “the question of whether some patients really need surveillance and whether further lengthening of intervals can be recommended in others,” they wrote.
Studies like these will be “crucial,” they added, “given that post-polypectomy surveillance colonoscopies have become an increasing burden on endoscopy units, patients, the economy, and medical resources. Available colonoscopy resources might be better used if shifted to initial high-quality screening and diagnosis and will continue to be the driving force in the decrease in colorectal cancer incidence and mortality that has been ongoing since 1975.” – by Adam Leitenberger
Disclosures: The researchers and editorial authors report no relevant financial disclosures.