ObjectiveTo establish and validate a predictive nomogram for predicting the risk of distant metastasis in colorectal signet-ring cell carcinoma based on the Surveillance, Epidemiology, and End Results (SEER) database. MethodsA retrospective analysis was conducted on clinical and pathological data of patients diagnosed with colorectal signet-ring cell carcinoma in the SEER database from 2004 to 2015, and they were randomly divided into training and validation sets at a ratio of 7∶3. Independent risk factors for distant metastasis (DM) in colorectal signet-ring cell carcinoma were screened out in the training set through univariate and multivariate logistic regression analysis, and a nomogram was constructed. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the discrimination, calibration, and clinical utility of the nomogram model. ResultsA total of 2 595 patients with colorectal signet-ring cell carcinoma were included, of whom 1 022 (39.4%) had DM. According to the univariate and multivariate logistic regression analysis, gender, age, T stage, N stage, surgical treatment, radiotherapy and chemotherapy were independent risk factors for DM of colorectal signet-ring cell carcinoma (P<0.05). Based on the above independent risk factors, a nomogram for DM of colorectal signet-ring cell carcinoma was constructed. The nomogram AUC of the ROC was 0.78 [ 95%CI (0.76, 0.80) ] and 0.77 [ 95%CI (0.74,0.81) ] in the training and validation sets, respectively. The calibration curves showed a good fit in the training and validation sets, with the Hosmer-Lemeshow test results being χ2=9.43, P=0.31 and χ2=12.47, P=0.13, respectively. The DCA curves showed that the model had a net benefit when the threshold probabilities of the training and validation sets were in the range of 10%–95% and 11%–990%, respectively. ConclusionThe nomogram constructed in this study exhibits higher accuracy and reliability, and can be used for early intervention and risk prediction of DM in colorectal signet-ring cell carcinoma.