Construction and Validation of a Nomogram to Predict Overall Survival in Patients with Inflammatory Breast Cancer

In the present study, we examined the factors affecting survival of women with inflammatory breast cancer (IBC) and constructed and validated a nomogram to predict overall survival (OS) in these patients. The cohort was selected from the Surveillance, Epidemiology, and End Results (SEER) program between 1 January 2004 and 31 December 2013. Univariate and multivariate Cox proportional hazards regression models were constructed. A nomogram was developed based on significant prognostic indicators of OS. The discriminatory and predictive capacities of the nomogram were assessed using Harrell's concordance index (C-index) and calibration plots. A total of 1651 eligible patients were identified, with a median survival time of 31 months (range 0-131 months), and the 3- and 5-year OS rates were 52.8% and 39.5%, respectively. Multivariate analysis revealed that race (P < .001), marital status (P = .011), N stage (P = .002), M stage (P < .001), hormone receptor (P < .001), human epidermal growth factor receptor-2 (HER2) (P = .001), surgery (P < .001), chemotherapy (P < .001), and radiotherapy (P = .010) were independent prognostic indicators of IBC. These nine variables were incorporated to construct a nomogram. The C-indexes of the nomogram were 0.738 (95% confidence interval [CI]: 0.717, 0.759) and 0.741 (95% CI: 0.717, 0.765) for the internal and external validations, respectively. The nomogram had a better discriminatory capacity for predicting OS than did the SEER summary stage (P < .001) or the American Joint Committee on Cancer tumor-node metastasis staging systems (8th edition; P < .001). The calibration plot revealed satisfactory agreement between the findings and predicted outcomes in both the internal and external validations. The nomogram-based 3- and 5-year OS predictions for patients with IBC exhibited superior accuracy over the existing models.