Prospective Study
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World J Gastroenterol. Nov 21, 2014; 20(43): 16306-16310
Published online Nov 21, 2014. doi: 10.3748/wjg.v20.i43.16306
Magnifying narrow-band imaging with acetic acid to diagnose early colorectal cancer
Norihiro Goto, Toshihiro Kusaka, Yumi Tomita, Hideyuki Tanaka, Yoshio Itokawa, Yorimitsu Koshikawa, Daisuke Yamaguchi, Yoshitaka Nakai, Shigehiko Fujii, Hiroyuki Kokuryu
Norihiro Goto, Toshihiro Kusaka, Yumi Tomita, Hideyuki Tanaka, Yoshio Itokawa, Yorimitsu Koshikawa, Daisuke Yamaguchi, Yoshitaka Nakai, Shigehiko Fujii, Hiroyuki Kokuryu, Department of Gastroenterology and Hepatology, Kyoto Katsura Hospital, Kyoto 615-8256, Japan
Author contributions: Goto N, Kusaka T, Fujii S and Kokuryu H designed the study; Goto N, Kusaka T, Tomita Y, Tanaka H, Itokawa Y, Koshikawa Y, Yamaguchi D, Nakai Y and Fujii S performed the colonoscopy; Goto N analyzed the data and wrote the manuscript.
Correspondence to: Norihiro Goto, MD, Department of Gastroenterology and Hepatology, Kyoto Katsura Hospital, 17 Yamada Hiraocho, Nishikyoku, Kyoto 615-8256, Japan. norihirogoto@hotmail.co.jp
Telephone: +81-75-3915811 Fax: +81-75-3923517
Received: March 17, 2014
Revised: June 8, 2014
Accepted: July 11, 2014
Published online: November 21, 2014
Processing time: 247 Days and 22.3 Hours
Abstract

AIM: To evaluate the diagnostic characteristics of magnifying endoscopy with acetic acid spray and narrow-band imaging (MA-NBI) for early colorectal cancer.

METHODS: We conducted a prospective study to evaluate the diagnostic characteristics of MA-NBI in differentiating early colorectal adenocarcinomas from adenomas. To compare the results, we used magnifying endoscopy with NBI (M-NBI) and magnifying endoscopy with crystal violet staining (M-CV). The study was performed in 2 phases. In phase 1, 10 colonoscopists at our institution were shown still photographs of 35 colorectal polyps (24 adenocarcinomas and 11 adenomas) in M-NBI, MA-NBI, and M-CV. They made diagnostic predictions using a five-grade scoring evaluation. We plotted receiver operating characteristic curves and compared the areas under the curves (AUCs). In phase 2, colorectal polyps measuring ≥ 8 mm were prospectively enrolled. During real-time colonoscopy, one of the 7 colonoscopists scored the lesion as an adenocarcinoma or an adenoma and assigned a level of confidence to the prediction (high or low). We calculated the accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for each method and compared the proportions of high-confidence predictions.

RESULTS: In phase 1, the mean ± SD AUCs were 0.64 ± 0.031 in M-NBI, 0.71 ± 0.066 in MA-NBI, and 0.76 ± 0.059 in M-CV (P < 0.05 for M-NBI vs MA-NBI, P < 0.001 for M-NBI vs M-CV, and not significant for MA-NBI vs M-CV). In phase 2, 84 patients with 91 lesions (46 adenocarcinomas and 45 adenomas) were enrolled. The diagnostic characteristics were as follows: 73% accuracy, 85% sensitivity, 60% specificity, 68% PPV, and 79% NPV in M-NBI; 73% accuracy, 80% sensitivity, 64% specificity, 70% PPV, and 76% NPV in MA-NBI; and 73% accuracy, 83% sensitivity, 62% specificity, 69% PPV, and 78% NPV in M-CV. The proportions of high-confidence predictions were 57% in M-NBI, 75% in MA-NBI, and 76% in M-CV (P < 0.005 for M-NBI vs MA-NBI, P < 0.0005 for M-NBI vs M-CV, and P = 1.0 for MA-NBI vs M-CV).

CONCLUSION: MA-NBI is useful for differentiating early colorectal adenocarcinomas from adenomas.

Keywords: Colorectal cancer; Endoscopy; Neoplasia; Narrow-band imaging; Acetic acid

Core tip: Differentiating early colorectal adenocarcinomas from adenomas using magnifying endoscopy with narrow-band imaging can sometimes be difficult because the surface pattern is frequently obscure. Magnifying endoscopy with acetic acid spray and narrow-band imaging (MA-NBI) accentuates the surface pattern of colorectal polyps. This study showed that MA-NBI and magnifying endoscopy with crystal violet staining (M-CV) are useful for differentiating early colorectal adenocarcinomas from adenomas. Moreover, MA-NBI is more time- and cost-effective than M-CV and could be beneficial for routine colonoscopies in terms of diagnostic accuracy, efficiency, and cost-effectiveness.