A prognostic index model for predicting overall survival in patients with metastatic castration-resistant prostate cancer treated with abiraterone acetate after docetaxel
Menée à partir de données portant sur 762 patients atteints d'un cancer métastatique de la prostate résistant à la castration et ayant reçu un traitement par docétaxel, acétate d'abiratérone et prednisone, puis validée sur 286 patients complémentaires, cette étude évalue la performance d'un modèle pronostique, basé sur six paramètres clinico-pathologiques (niveau sérique de la lactate déshydrogénase, présence de métastases hépatiques, ...), pour stratifier les patients
Background : Few prognostic models for overall survival (OS) are available for patients with metastatic castration-resistant prostate cancer (mCRPC) treated with recently approved agents. We developed a prognostic index model using readily available clinical and laboratory factors from a phase III trial of abiraterone acetate (hereafter abiraterone) in combination with prednisone in post-docetaxel mCRPC.
Patients and methods : Baseline data were available from 762 patients treated with abiraterone-prednisone. Factors were assessed for association with OS through a univariate Cox model and used in a multivariate Cox model with a stepwise procedure to identify those of significance. Data were validated using an independent, external, population-based cohort.
Results : Six risk factors individually associated with poor prognosis were included in the final model: lactate dehydrogenase>upper limit of normal (ULN) (hazard ratio [HR]=2.31), Eastern Cooperative Oncology Group performance status of 2 (HR=2.19), presence of liver metastases (HR=2.00), albumin≤4 g/dl (HR=1.54), alkaline phosphatase>ULN (HR=1.38) and time from start of initial androgen-deprivation therapy to start of treatment≤36 months (HR=1.30). Patients were categorized into good (n=369, 46%), intermediate (n=321, 40%) and poor (n=107, 13%) prognosis groups based on number of risk factors and relative HRs. The C-index was 0.70±0.014. The model was validated by the external dataset (n=286).
Conclusion : This analysis identified six factors used to model survival in mCRPC and categorized patients into three distinct risk groups. Prognostic stratification with this model could assist clinical practice decisions for follow-up and monitoring, and may aid in clinical trial design.
Annals of Oncology , résumé, 2015