Assessing the impact of bowel preparation quality on colorectal cancer effectiveness: a study with unexpected results

Aims The aims of our study were to assess whether there was an association between the adequacy of bowel preparation and both adenoma detection rate and the advanced adenoma detection rate, and to investigate whether there was a correlation between the quality of preparation and the number of adenomas detected per colonoscopy.

Methods We present a retrospective, single-center study of complete screening colonoscopies performed on patients with 50 years old or more, over 18 months (from April 2022 to September 2023), and their respective histological reports. Adequate preparation was considered if all colonic segments scored 2 or more points on the Boston Bowel Preparation Scale (BBPS). Adenomas that are 1 cm or larger, exhibit high-grade dysplasia, or have a villous architecture were considered advanced adenomas. Statistical analysis was conducted using SPSS v29.0.

Results 672 total colonoscopies were analyzed. The average age was 64.5±8.0 years, and there was no predominance between genders. BBPS scores ranged from 0 to 9. The majority of patients had adequate bowel preparation (74%, n=502), with BBPS scores of 6, 7, 8, and 9 in 37.7%, 7.0%, 22.9%, and 7% of cases, respectively. The adenoma detection rate was 41.2% and the detection rate of advanced adenomas was 16.4%. The number of adenomas detected per colonoscopy ranged from 0 to 11 adenomas. No association was found between having adequate preparation and having at least 1 adenoma (p>0.05) or having at least 1 advanced adenoma (p>0.05). There was no statistically significant difference in the average number of adenomas per colonoscopy between patients with and without adequate preparation (p>0.05). There was no correlation between the BBPS score and the number of adenomas per colonoscopy (p>0.05).

Conclusions The detection rates of adenomas and advanced adenomas were not associated with the adequacy of bowel preparation. No correlation was found between the quality of preparation and the number of adenomas per colonoscopy. Despite the need to repeat another colonoscopy with adequate BBPS for optimal observation of the mucosa, concluding screening procedures in patients with inadequate bowel preparation has still proven to be useful. As long as it is considered safe, endoscopists should be encouraged to conclude all screening procedures.

Publication History

Article published online:
27 March 2025