Predictors for underestimated pathology in forceps biopsy compared with resection specimen of colorectal neoplasia; focus on surface appearance

Abstract

Background There have been substantial differences in pathologic results between forceps biopsies (FB) and resection specimen (RS) of the colorectal neoplasm. The aim of this study was to investigate predictive factors of the underestimated pathology in FB compared with RS. Methods Data from 248 consecutive patients with colorectal intraepithelial neoplasm C10 mm, which was removed by endoscopic mucosal resection or endoscopic submucosal dissection, were reviewed retrospectively. We excluded patients with no FB on the neoplasm before the resection. Demographic data and tumor characteristics including size, locations, surface appearances, and the number of FB fragments were evaluated as potential factors associated with the discrepancies by logistic regression analysis. Results Overall, 179 lesions from 171 patients were included in the study (size, 28.37 ± 12.00 mm; range 10–80 mm). The overall number of discrepancy cases was 103 (57.5 %), where 90 (50.3 %) were underestimated in FB and 13 (7.2 %) downgraded in their RS. In the multivariate analysis, round [odds ratio (OR) 4.46, 95 % confidence interval (CI) 1.76–11.30, p = 0.002], depressed (OR 3.23, 95 % CI 1.11–9.39, p = 0.031), and mixed type of surface appearance (OR 5.47, 95 % CI 2.38–12.60, p\0.001), and tumor size C30 mm (OR 2.14, 95 % CI 1.12–4.10, p = 0.021) were significant predictive factors for underestimated pathology in FB. Conclusions Underestimation in FB is remarkable in colorectal tumors C10 mm in size. This discrepancy is associated with the tumor characteristics, such as surface appearance and size. Endoscopic characteristics of tumor should be carefully examined for an adequate management strategy of colorectal epithelial neoplasm. Keywords Colorectal neoplasm Discrepancy Endoscopic resection Forceps biopsy Colorectal neoplastic lesions are called superficial when their depth is limited to the mucosa and submucosa [1]. Thus, superficial colorectal neoplasia includes intraepithelial neoplasia (adenomas, dysplasia, and premalignancy) in the mucosa and invasive lesions categorized as intramucosal or submucosal cancers. These lesions can be treated by endoscopic management such as endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD). Although ESD is technically demanding, it results in a high en bloc complete resection rate and is often the preferred option for suspicious cancer lesions, which requires precise histological evaluation [2, 3]. In the case of superficial cancers with deep submucosal invasion (sm2 or sm3), surgical treatment should be considered because of the risk of lymph node metastasis [4]. In addition, it is not necessary to remove nonneoplastic lesions, such as hyperplastic or inflammatory polyps. Therefore, it is crucial to determine histological features or the invasion depth of tumors for selecting an optimal management strategy. Cold biopsy by forceps before resection still appears to be used in real clinical practice, particularly for large tumors, for which a one-stage polypectomy might not be available. There has been increasing evidence of substantial difference in the pathologic results between forceps biopsies (FB) and resection specimen (RS) of gastric epithelial tumors [5–8]. However, few studies have evaluated and compared the concordance rate between FB and RS of large colorectal tumors. Therefore, the aim of this study was to estimate the discrepant pathologic diagnosis between FB and RS of colorectal epithelial tumors that are C10 mm in size and to investigate predictive factors of these discrepancies with a focus on the surface appearance of the tumors. In addition, we also evaluated the endoscopic characteristics of colorectal cancers associated with submucosal invasiveness.