Survival analysis and development of a prognostic nomogram for bone-metastatic prostate cancer patients: A single-center experience in Indonesia

Objectives: To analyze predictive clinical factors of survival in bone-metastatic prostate cancer, and to develop a prognostic nomogram for patients with this condition. Methods: The present study included 392 patients with bone-metastatic prostate cancer treated with androgen deprivation therapy. Pretreatment parameters were analyzed using the Cox proportional hazards model to identify the predictors of overall survival. Covariates – which showed statistical significance on multivariate analysis – were used to develop a nomogram. A linear predictor model was utilized to develop the nomogram. Results: The median overall survival was 40.3 months (95% confidence interval 32.2–48.5). Univariate analysis showed that clinical T stage, Gleason score, initial prostate-specific antigen value and the number of metastatic lesions were independent prognostic factors for overall survival. These predictors remained significant as independent prognostic factors for overall survival after analysis using the multivariate Cox regression model. The nomogram constructed from those prognostic factors showed good discrimination for predicting the 5-year overall survival, with an area under the curve of 0.69. Acceptable agreement of the observed and predicted probabilities was observed in the calibration plot. Conclusions: The present prognostic nomogram might be a useful tool for predicting overall survival in pretreatment bone-metastatic prostate cancer, specifically among Indonesian patients. Further studies are required to provide external validation to support the utilization of this nomogram.