Application of a nomogram in detection of lymph node metastases in T1 colorectal cancer

Objective: The aim of this study was to establish a simple nomogram as a reference measure to predict lymph node metastases (LNM) in stage T1 colorectal cancer patients, ultimately aiding in the development of treatment strategies. Materials and methods: This study retrospectively analyzed 19,238 patients with pathological stage T1NanyM0 colorectal cancer who underwent surgical resection from 1998 to 2011 according to the Surveillance Epidemiology and End Results (SEER) database. Clinicopathological risk factors of LNM were identified by univariate and multivariate logistic regression analyses. A nomogram to predict the probability of LNM for T1 colorectal cancer was developed from the multivariate logistic regression model. Results: In total, 14.4% of the T1 colorectal cancer patients had pathological LNM. The multivariate analysis indicated that independent risk factors for LNM included the patient's age (P<0.001), race (P<0.001), tumor site (P<0.001), grade (P<0.001), histological differentiation and tumor size (P<0.001). A nomogram consisting of these six factors was developed and predicted the LNM status with a concordance index (c-index) of 0.66. The nomogram showed a good calibration with a 200 bootstrapping corrected c-index of 0.66. Conclusion: A nomogram based on patient's age, race, tumor site, grade, and tumor size is a useful tool to predict the LNM status of T1 colorectal cancer patients.