Abstract

The index of hemoglobin (IHb) has not been applied in colonoscopy to correlate the histological features of colon polyps. This study tested whether the net change of IHb values between polyp and normal mucosa correlates with the pathological features of colon polyps. This study consecutively enrolled patients who underwent colonoscopy during September 2011–August 2012 in a single tertiary referral colorectal unit. Endoscopic pictures and IHb values of each part of the colon were taken at the levels of cecum, ascending colon, transverse colon, sigmoid colon, and rectum. The net change of IHb values was calculated as follows: IHb value of colon polyp minus that of the surrounding mucosa. A total of 117 patients (32 with hyperplastic polyp, 5 with sessile serrated adenoma, 53 with tubular adenoma, 10 with villotubular adenoma, and 3 with adenocarcinoma) were recruited. The net change of IHb values increased in following order: hyperplastic polyp, tubular adenoma, sessile serrated adenoma, villotubular adenoma, and adenocarcinoma (−3.8 ± 6.3, −1.2 ± 1.7, −1.2 ± 5.7, 2.9 ± 8.1, and 12.7 ± 9.3, respectively, p < 0.001). Alcohol drinking and serum hemoglobin level were two independent factors related to the IHb values of non-polyp colon mucosa. Using a cutoff value of 2.4 for the net change of IHb values, selected based on the receiver operating characteristic curve analysis, the optimal sensitivity (52.9%) and specificity (75.6%) could be achieved for defining the polyp histology as an advanced colon lesion. The net change of IHb values between colon polyp and nonpolyp mucosa can correlate with the pathological features of colon polyps. A positive net change of IHb values may indicate a more adverse histological pattern with a higher malignant potential.