Objective To investigate the risk factors for submucosal invasive carcinoma developed by colorectal laterally spreading tumor of granular type(LST-G).

Methods A total of 320 patients with colorectal LST-G admitted to the Department of Gastroenterology were retrospectively selected as study subjects, all of them underwent endoscopic submucosal dissection (ESD). According to the postoperative pathological results, the patients were divided into submucosal invasive carcinoma group (36 cases) and non-occurrence of submucosal invasive carcinoma group (284 cases). General data and pathological characteristics of the two groups were compared, and multivariate Logistic regression analysis was used to explore the risk factors of submucosal invasive carcinoma developed by colorectal LST-G. Receiver operating characteristic (ROC) curve was drawn; the area under the curve (AUC) was calculated. The diagnostic efficacy of the lesion diameter and maximum nodule diameter combined with location of the lesion in the rectum for submucosal invasive carcinoma developed by colorectal LST-G was evaluated.

Results The proportion of patients with family history of colorectal cancer, lesion diameter, maximum nodule diameter and proportion of patients with site of lesion in the rectum in the submucosal invasive carcinoma group were higher or more than those in the non-occurrence of submucosal invasive carcinoma group (P < 0.001). Multivariate Logistic regression analysis showed that family history of colorectal cancer, lesion diameter≥38.25 mm, maximum nodule diameter≥14.33 mm and site of lesion in the rectum were risk factors for submucosal invasive carcinoma developed by colorectal LST-G (OR=16.994, 95%CI, 1.409 to 198.265, P=0.027; OR=1.308, 95%CI, 1.008 to 1.721, P=0.041; OR=28.654, 95%CI, 4.615 to 187.265, P < 0.001; OR=1.411, 95%CI, 1.015 to 1.819, P=0.033). The AUC of lesion diameter and maximum nodule diameter combined with site of lesion in the rectum in the diagnosis of submucosal invasive carcinoma developed by colorectal LST-G was 0.891 (95%CI, 0.814 to 0.932), the sensitivity was 89.82%, and the specificity was 75.37%, which were significantly better than the diagnostic efficiency of the lesion diameter and maximum nodule diameter separately combined with site of lesion in the rectum(Z=2.678, P=0.007; Z=3.188, P=0.001).

Conclusion Family history of colorectal cancer, lesion diameter≥38.25 mm, maximum nodule diameter≥14.33 mm, and site of lesion in the rectum are the risk factors of submucosal invasive carcinoma developed by colorectal LST-G. Lesion diameter, maximum nodule diameter combined with site of lesion in the rectum has the best efficacy in diagnosis of submucosal invasive carcinoma developed by colorectal LST-G.