Nomogram for predicting the survival outcome of cabazitaxel treatment in patients with metastatic castration-resistant prostate cancer: A multi-institutional analysis

Background: Cabazitaxel (CBZ) is the mainstay of treatment for metastatic castration-resistant prostate cancer (mCRPC). In the present study, we developed a nomogram to predict the individual survival probability after CBZ treatment in patients with mCRPC. Methods: We retrospectively analyzed 345 patients with mCRPC who started CBZ treatment between September 2019 and March 2024 and randomly divided them into a development cohort (n=230) and a validation cohort (n=115). We investigated several potential risk factors for a poor overall survival (OS) using the Cox proportional hazard model and developed a nomogram to predict the 1-year survival probability. The accuracy and discrimination ability of the nomograms were evaluated according to Harrell's concordance index (C-index) and calibration plot. Results: We developed a nomogram predicting the 1-year survival probability with predictors including ECOG-PS ≥2, presence of liver metastasis, an initial PSA ≥30 ng/mL, a PSADT ≤3 months, radiological progression of disease during docetaxel, Hb ≤12 g/dL, and LDH ≥250 U/L. C-indices of our Cox hazard model at internal validation and external validation were 0.72 and 0.67, respectively. The model was adequately calibrated, and their predictions were correlated with the observed outcomes in both cohorts. The OS was significantly different among the risk groups defined by the total points calculated from the nomogram in both cohorts. Conclusion: Our validated nomogram, which is predictive of the survival outcome after CBZ treatment in patients with mCRPC, may help in individual clinical decision-making.