Nomogram for individually predicting overall survival in rectal neuroendocrine tumours

Background This study aimed to develop a nomogram that predicts the overall survival (OS) of rectal neuroendocrine tumours (NETs). Methods We retrospectively analysed 310 patients with rectal neuroendocrine tumours in 5 hospitals in southern China. All of the patients were assigned to the training set. A multivariable analysis using Cox proportional hazards regression was performed using the training set, and a nomogram was constructed. It was validated on a dataset obtained from the Surveillance, Epidemiology, and End Result (SEER) database of America ( n = 547). Results In the training set, the nomogram exhibited improved discrimination power compared with the WHO grade guidelines (Herrell’s C-index, 0.872 vs 0.794; p < 0.001) and was also better than the seventh AJCC TNM classification (Herrell’s C-index, 0.872 vs 0.817; p < 0.001). In the SEER validation dataset, the discrimination was also excellent (C-index, 0.648 vs 0.583, p < 0.001 and 0.648 vs 0.603 , p = 0.016 , respectively, compared with G grade and TNM classification). Calibration of the nomogram predicted individual survival corresponding closely with the actual survival. Conclusions We developed a nomogram predicting 1- and 3-year OS of patients with rectal neuroendocrine tumours. Validation revealed excellent discrimination and calibration, suggesting good clinical utility.