Predictive factors for abiraterone withdrawal syndrome.

INTRODUCTION AND

OBJECTIVE

Abiraterone withdrawal syndrome (AWS) is characterized by a transient decrease in the PSA after abiraterone acetate (AA) treatment discontinuation in patients diagnosed with metastatic castration-resistant prostate cancer (mCRPC). The aim of our study is to identify the possible predictive factors of AWS at diagnosis.

MATERIALS AND

METHODS

We performed a retrospective study of 70 patients treated with AA at the Institut Català d'Oncologia - L'Hospitalet between 2015 and 2017.

RESULTS

11 patients presented AWS. The mean age at diagnosis was 65.73 years and the mean age of presentation was 74.18 years. Patients were in the ninth treatment cycle. The median PSA was: 30.5ng/ml at diagnosis, 33.24ng/ml in the AWS, and 15.78ng/ml before starting another treatment. The median follow-up period after AWS was 8.2 months. The predictive factors of AWS would be: high PSA (p=.002), ISUP≥4 (p=.002) and stage IV at diagnosis (p<.001). Patients with a T stage present high risk, but without statistical significance. An AUC of 0.84 was obtained, with a 95% CI between 0.77 and 0.92 (p<.001).

CONCLUSIONS

The incidence of AWS is not negligible, describing prolonged responses after AA withdrawal, including the possibility of increased overall survival. These results could entail new treatment schemes for mCRPC.