Development and Validation of the First Multi-Racial Prognostic Nomogram for Patients with Bone Metastatic Prostate Cancer Worldwide

Abstract

Background: The independent prognostic factors for survival of patients with bone metastatic prostate cancer (PCa) remain controversial; Besides, a nomogram for application to multiple ethnicities has yet to be established. We aimed to build a generic nomogram to predict the prognosis of bone metastatic PCa. Methods: The independent prognostic factors for survival were identified, and the nomogram was further developed in a retrospective study of 1,556 patients with bone metastatic PCa registered in the Surveillance, Epidemiology and End Results (SEER) database. The discriminative ability of the nomogram was assessed by C-index (concordance index) and ROC (receiver operating characteristic) curve analysis, whereas its predictive accuracy was measured by calibration curve assessment. Furthermore, the model was externally validated using the data of 711 patients enrolled in the same database at different times. Results: Age ≥70 years, Gleason score ≥8, stage T4, stage N1, liver metastases, and Asian/Pacific ethnicity were identified as independent prognostic factors. The C-index of the nomogram for predicting cancer-specific survival (CSS) was 0.68 (95% confidence interval [CI]: 0.65-0.70), with areas under the receiver operating characteristic (ROC) curve (AUCs) for one, three, and five years of 0.70, 0.70, and 0.76, respectively. In the validation cohort, the C-index was 0.66 (95% CI: 0.62 to 0.69), with AUCs for one, three, and five years of 0.67, 0.66 and 0.71, respectively. The calibration curve presented a strong agreement between the nomogram-predicted and actual one-, three-, and five-year CSSs in both the primary and external validation cohorts. Conclusion: We established and validated the first nomogram applied to multiple races for predicting the one-, three-, and five-year CSSs of patients with bone metastatic PCa, which will further facilitate individualized clinical decision-making and will be useful for patient counseling. Funding: This study is supported by the Key Science and Technology Program of Shaanxi Province, PR China (grant number: 2016SF-162) and the Development Funds of Shaanxi Science and Technology Agency of China (grant number:2018SF/091). Declaration of Interest: There are no conflicts of interest. Ethical Approval: The present study conformed to the 1964 Helsinki Declaration and its later amendments and was performed under the ethical standards of the institutional and national research committees.