Effects of apalutamide dose reduction on skin‐related adverse events in patients with advanced prostate cancer: A multicenter retrospective study

Background We aimed to evaluate the effects of apalutamide dose reduction on skin‐related adverse events (AEs) and castration‐resistant prostate cancer (CRPC)‐free survival in patients with advanced prostate cancer (PC). Methods We retrospectively evaluated 35 patients with nonmetastatic CRPC and 72 patients with treatment‐naïve metastatic castration‐sensitive PC (mCSPC) who were treated with apalutamide. The primary outcome was the effect of apalutamide dose reduction on skin‐related AEs. The secondary outcomes were the effect of apalutamide dose reduction on skin‐related AEs in patients with small body size, postskin AE apalutamide discontinuation rate, and CRPC‐free survival in patients with mCSPC treated with upfront apalutamide plus androgen deprivation therapy. Results Of the 107 patients, 65 (60.7%) and 42 (39.3%) were treated with full and reduced doses of apalutamide, respectively. The skin‐related AE rate was not significantly different between the groups (55% vs. 43%, p = 0.761). In the group receiving reduced apalutamide dose, the incidence of skin‐related AEs was significantly lower in patients with small body sizes (body weight