Minor residual staining found adequate for colonoscopy

A Boston Bowel Preparation Scale (BBPS) score of 2 – indicating mild residual staining and small stool fragments – was as good as the optimal preparation score of 3 for visualizing polyps and adenomas larger than 5 mm and advanced adenomas during colonoscopy, researchers said.

A score of 2 might increase the chances of missing smaller polyps, but is adequate for detecting clinically significant masses, Dr. Brian Clark of Yale University, New Haven, Conn., and his associates reported in the February issue of Gastroenterology. But a score of 1 – meaning that there is enough staining or stool to obscure the mucosa – significantly increased the chances of missing adenomas larger than 5 mm, they said. Patients should undergo early repeat colonoscopy if their BBPS score is 1 or 0 in any colon segment, they emphasized.

Source: American Gastroenterological Association

Bowel preparation for colonoscopy is considered adequate if endoscopists can detect polyps larger than 5 mm, but no prior study had quantified the amount of preparation needed. This prospective observational study assessed adequate preparation in terms of the BBPS, which scores each of three colon segments on a scale of 0 (solid stool covering the mucosa) to 3 points (entire mucosa seen well, with no residual staining). Study participants included 438 men aged 50-75 years who underwent screening or surveillance colonoscopy at a single Veterans Affairs center, followed by repeat colonoscopies within 60 days performed by different blinded endoscopists. The investigators excluded patients who scored 0 in all colon segments or had familial polyposis syndrome, inflammatory bowel disease, polyps so large that they could not be completely removed, or a history of colonic or rectal resection. In all, they analyzed 1,161 colon segments (Gastroenterology. 2015 Dec 7. doi: 10.1053/j.gastro.2015.09.041).

Endoscopists missed about 5% of adenomas greater than 5 mm, regardless of whether BBPS scores were 2 or 3 in a model that accounted for age, reason for colonoscopy, colon segment, number of polyps removed in the first examination, and endoscopist performing the procedure, the researchers said. But when BBPS scores were 1, endoscopists missed 16% of adenomas larger than 5 mm, a difference of about 10%. Furthermore, 43% of screening and surveillance intervals would have been incorrect had they been based solely on an initial examination for which scores were 1 in at least one segment. In contrast, only about 15% of intervals would have been incorrect for patients who scored 2 or 3 in all segments.

In all, 80% of patients were sufficiently prepared, having scored at least 2 in all segments on the first examination. “Determining whether a patient’s preparation quality is adequate is one of the most common and important decisions made by gastroenterologists each day,” the researchers said. Between 25% and 30% of screening and surveillance colonoscopies occur at “inappropriately shortened intervals,” often because of uncertainty about what constitutes adequate visualization, they added. Defining adequate visualization based on bowel preparation could save billions of dollars in health care costs every year, minimize complications from unnecessary procedures, and pinpoint those patients who truly need an early repeat colonoscopy to help prevent interval colorectal cancer, they emphasized.

The National Institutes of Health funded the study. The investigators had no disclosures.