Chicken skin mucosa surrounding small colorectal cancer could be an endoscopic predictive marker of submucosal invasion

BACKGROUND: Chicken skin mucosa (CSM) surrounding colon polyps is a common endoscopic finding with pale yellow-speckled mucosa during a colonoscopy screening. Although reports about CSM surrounding small colorectal cancer are scarce, and its clinical significance in intramucosal and submucosal cancers is unclear, previous studies have suggested it could be an endoscopic predictive marker for colonic neoplastic and advanced polyps. Currently, because of the inaccurate preoperative evaluation by endoscopists, many small colorectal cancers, particularly lesions with a diameter < 2 cm, are improperly treated. Therefore, more effective methods are required to better assess the depth of the lesion before treatment. AIM: To explore potential markers of small colorectal cancer early invasion under white light endoscopy, providing patients with better treatment alternatives. METHODS: This retrospective cross-sectional study included 198 consecutive patients [233 early colorectal cancers (ECCs)] who underwent endoscopy or surgical procedures at the Digestive Endoscopy Center of Chengdu Second People’s Hospital between January 2021 and August 2022. The participants had pathologically confirmed colorectal cancer with a lesion diameter < 2 cm and received endoscopic or surgical treatment, including endoscopic mucosal resection and submucosal dissection. Clinical pathology and endoscopy parameters, including tumor size, invasion depth, anatomical position, and morphology, were reviewed. Fisher’s exact test, the χ(2) test, and Student’s t-test were used to analyze the patient’s basic characteristics. Logistic regression analysis was used to examine the relationship between morphological characteristics, size, CSM prevalence, and ECC invasion depth under white light endoscopy. Statistical significance was set at P < 0.05. RESULTS: The submucosal carcinoma (SM stage) was larger than the mucosal carcinoma (M stage) with a significant difference (17.2 ± 4.1 vs 13.4 ± 4.6 mm, P < 0.01). M- and SM-stage cancers were common in the left colon; however, no significant differences were found between them (151/196, 77% and 32/37, 86.5%, respectively, P = 0.199). The endoscopic features of colorectal cancer revealed that CSM, depressed areas with clear boundaries, and erosion or ulcer bleeding were more common in the SM-stage cancer group than in the M-stage cancer group (59.5% vs 26.2%, 46% vs 8.7%, and 27.3% vs 4.1%, respectively, P < 0.05). CSM prevalence in this study was 31.3% (73/233). The positive rates of CSM in flat, protruded, and sessile lesions were 18% (11/61), 30.6% (30/98), and 43.2% (32/74), respectively, with significant differences (P = 0.007). CONCLUSION: CSM-related small colorectal cancer was primarily located in the left colon and could be a predictive marker of submucosal invasion in the left colon.