Impact of acetic acid chromoendoscopy on detection of serrated lesions in the proximal colon compared with white-light endoscopy

Background and study aims: Colorectal cancer (CRC) screening programs demonstrated a significant reduction in distal CRC mortality. However, similar results are not observed in proximal cancer, probably due to subtle and easily overlooked serrated lesions (SLs) that account for up to 30% of cases. Acetic acid chromoendoscopy may be useful in characterization of SLs. Data on its impact on SL detection rates remain limited. The aim of this study was to assess SL detection rates using high-definition white-light endoscopy (HD-WLE) versus sequential HD-WLE followed by 2% acetic acid chromoendoscopy (AAC) in the proximal colon and to evaluate the association between proximal SL rates and risk factors. Patients and methods: This prospective study included colonoscopies performed at a tertiary care center in patients aged ≥ 18 years between January and July 2021. HD-WLE was followed by HD-WLE with 2% acetic acid chromoendoscopy (AAC). SL detection rates were analyzed using McNemar's test, and risk factors were evaluated using multivariable logistic regression. Results: Four hundred thirty-four patients aged 18 to 82 years underwent both inspection strategies. Among proximal lesions, 60.9% were detected under HD-WLE and 39.1% after AAC (P < 0.001). Proximal SL detection increased from 36.6% with HD-WLE to 63.4% after AAC (<i>P</i> = 0.016). After adjustment, hypertension was associated with a higher likelihood of proximal SL detection (odds ratio 2.28; <i>P</i> = 0.032). <b>Conclusions:</b> HD-WLE with sequential application of 2% acetic acid chromoendoscopy was associated with higher proximal SL detection compared with HD-WLE alone. Hypertension was the only risk factor significantly associated with proximal SL detection, within the context of a sequential examination design