Development and validation of the nomogram for predicting cancer-specific survival in patients with muscle-invasive bladder cancer after radical cystectomy

Abstract

Background Accurate survival prediction in muscle-invasive bladder cancer (MIBC) is critical for clinical decision-making. The study aimed to build and validate a practical nomogram to predict the cancer-specific survival (CSS) and assist to formulate clinical-decision for patients with MIBC. Methods The data of 5,474 MIBC patients who underwent radical cystectomy were included from the SEER database between 2004 and 2014. These patients were randomly divided into training cohort and validation cohort with a 7:3 ratio. The nomogram for predicting the CSS was constructed on the basis of univariate and multivariate Cox regression analyses. Kaplan–Meier curves were used to compare the survival patterns in the different subgroups. Finally, the model was assessed by the concordance index (C-index), receiver operating characteristic curve (ROC), area under the curve (AUC) and calibration plot. Results A total of 5,474 patients diagnosed with MIBC were identified and randomized into training (n = 3,832) and validation (n = 1,642) cohort. Multivariate analysis revealed that age, race, T stage, N stage, tumor size, regional nodes positive and neoadjuvant chemotherapy were independent prognostic factors of CSS and were integrated to develop a nomogram for predicting prognosis. Kaplan-Meier curves showed all these variables could influence the prognosis of MIBC patients. The C-indexes of the nomogram were 0.698 (0.685–0.709) in training cohort and 0.685 (0.665–0.705) in validation cohort, respectively. The AUCs of the nomogram were 0.747 for 3-year survival, 0.75 for 5-year survival in the training cohort and 0.742 for 3-year survival, 0.739 for 5-year survival in the validation cohort, respectively. The calibration plots also showed good performance. All the patients were divided into high-risk group and low-risk group based on our model, significant survival difference was also observed between high and low risk groups (P < 0.001). Conclusion We have created a nomogram to predict the cancer-specific survival for MIBC patients underwent radical cystectomy, which may provide a reference for clinical decision-making of postoperative treatment and improve prognosis for individual patients.