Impact of Novel Hormonal Agents (Abiraterone, Enzalutamide) on the Development of Visceral and/or Brain Metastases in Patients With Bone-metastatic Castration-resistant Prostate Cancer.

INTRODUCTION

The overall survival (OS) of metastatic castration-resistant prostate cancer (mCRPC) patients has improved since 2011 with the use of novel hormonal agents (NHAs). The incidence of brain metastases (mets) has been reported to increase since 2004 with the use of docetaxel, but not the incidence of visceral mets. Our objective was to study whether the use of NHAs increases the risk of developing visceral or brain mets (VBMs).

PATIENTS AND METHODS

mCRPC patients with mets limited to bone (bmCRPC), treated at Tours University Hospital between 2007 and 2015, were included retrospectively. The primary endpoint was to determine whether treatment with NHAs was associated with an increased incidence of VBMs. Secondary endpoints included the search for putative predictive factors to develop VBMs.

RESULTS

On 187 bmCRPC patients included, 65 developed VBMs. VBM incidence increased in bmCRPC patients alive after 2011, compared to patients who died before (39.7 vs. 24.6%, P = .04). Meanwhile, their median OS increased from 16.3 months to 28.5 months (P = .01). The longer was the treatment with NHAs, the lower was the risk of VBMs (HR = 0.96, 95% CI [0.94; 0.99]), whereas age < 70 years (HR = 3.33, 95% CI [1.50; 7.40]) and low PSA level at diagnosis (HR = 1.58, 95% CI [1.16; 2.15]) increased this risk.

CONCLUSION

Though retrospective, our results showed an increased incidence of VBMs in bmCRPC patients after 2011. However, this was not associated with NHA exposure duration. The role of NHA exposure remains unclear and needs further investigation.