# Implementing narrow banding imaging with dual focus magnification for histological prediction of small rectosigmoid polyps in Vietnamese setting

## TL;DR

This study shows that using narrow band imaging with dual focus magnification improves accuracy in predicting small rectosigmoid polyps' neoplastic status, supporting a safer and cost-effective 'diagnose-and-leave' strategy.

## Contribution

The study introduces dual focus magnification with narrow band imaging for real-time diagnosis of small rectosigmoid polyps in a Vietnamese setting.

## Key findings

- NBI with dual focus magnification significantly increased high-confidence optical diagnoses for diminutive polyps.
- The 'diagnose-and-leave' strategy could reduce 58.2% of unnecessary polypectomies without missing advanced neoplastic lesions.
- WLE + NBI + NBI-DF achieved 90.1% sensitivity and 95.5% specificity in high-confidence predictions.

## Abstract

Small rectosigmoid colorectal polyps (<10 mm) are prevalent, with a low prevalence of advanced neoplastic lesions. The “diagnose‐and‐leave” strategy, employing narrow band imaging (NBI), is gaining popularity for its safety and cost‐effectiveness by reducing polypectomy complications and minimizing histopathology expenses. This study assessed the diagnostic efficacy of NBI with dual focus (DF) magnification for real‐time neoplastic prediction of rectosigmoid polyps and explored the feasibility of implementing this strategy in Vietnam.

In a prospective single‐center study, 307 rectosigmoid polyps from 245 patients were analyzed using three consecutive endoscopic modes: white light endoscopy (WLE), NBI, and NBI‐DF. Endoscopists assessed polyps for size, location, macroscopic shape, optical diagnosis, and confidence levels before histopathological evaluation. High confidence was assigned when the polyp exhibited all features of a single histology type. Predictions were compared with final histopathology results.

Of the total, 237 (77.2%) were diminutive (≤5 mm) polyps, and 18 (5.8%) were advanced neoplastic lesions. WLE + NBI and WLE + NBI + NBI‐DF exhibited significantly higher accuracy compared to WLE (88.6% and 90.2% vs 74.2%, P < 0.01). For diminutive polyps, the DF mode significantly increased the rate of high‐confidence optical diagnoses (89.1% vs 94.9%, P < 0.001). WLE + NBI + NBI‐DF demonstrated high sensitivity (90.1%), specificity (95.5%), and negative predictive value (93.4%) in high‐confidence predictions, enabling the implementation of the “diagnose‐and‐leave” strategy. This approach would have reduced 58.2% of unnecessary polypectomies without missing any advanced neoplastic lesions.

NBI and DF modes provide accurate neoplastic predictions for rectosigmoid polyps. For diminutive polyps, DF magnification improves the confidence level of the optical diagnosis, allowing the safe implementation of the “diagnose‐and‐leave” strategy.

This study assessed the diagnostic efficacy of NBI with dual focus (DF) magnification for real‐time neoplastic prediction of diminutive rectosigmoid polyps. WLE + NBI and WLE + NBI + NBI‐DF exhibited significantly higher accuracy compared to WLE. The DF mode significantly increased the rate of high‐confidence optical diagnoses. WLE + NBI + NBI‐DF demonstrated high sensitivity (90.1%), specificity (95.5%), and negative predictive value (93.4%) in high‐confidence predictions, enabling the implementation of the “diagnose‐and‐leave” strategy.