Influence of abiraterone and enzalutamide on body composition in patients with metastatic castration resistant prostate cancer

INTRODUCTION: Loss of skeletal muscle (SM) and gain of subcutaneous fat (SCF) are known side-effects of androgen-deprivation in treatment of prostate cancer. Scarce data is available concerning the effects of abiraterone/pred (ABI) on body composition and no published data regarding enzalutamide (ENZA). Our objective was to analyse the effects of ENZA on SM/SCF and to compare the results with ABI in patients with metastatic castration-resistant prostate-cancer (mCRPC).

PATIENTS AND METHODS: 54 patients starting ABI (n = 17) or ENZA (n = 37) at a single-centre between 2012 and 2018 were retrospectively identified. SM and SCF were assessed using CT-scans at baseline and after a median of 10.8 months on treatment. A deep learning image-segmentation software was used to quantify SM and SCF. In a subgroup of patients receiving ENZA within a trial, we investigated change of SM using serial timepoints.

RESULTS: Median time of treatment with ABI/ENZA was 14.6 months. A significant loss of SM compared to baseline was observed for ENZA (mean loss 5.2%, p<0.0001) and ABI (mean loss 3.0%, p = 0.02). SCF was not significantly altered. The effects of both drugs did not differ significantly. Loss of SM occurred early on during treatment with ENZA.

CONCLUSION: Treatment with ENZA seems to lead to a loss of SM which is comparable to that of ABI. Further evaluation in larger patient-cohorts is warranted. In routine care, counselling of patients about side effects of ABI/ENZA should include discussions about SM loss.