My brother has CRPC and is receiving Cabazitaxel+Relugolix. Denosumab and Zoledronic acid don't work for him. I suggested an Estrogen patch to both maintain bone density and ameliorate hot flashes. His oncologist said that an Estrogen patch would interfere with the Cabazitaxel. I can't find any literature in the subject. Does anyone have any info on an interaction between Estrogen and Cabazitaxel?