Nonmetastatic castration-resistant prostate cancer (nmCRPC) is defined by a rising prostate-specific antigen (PSA) level despite testosterone castration, without evidence of bone, visceral, or distant extrapelvic nodal metastases, for a man with histologically confirmed prostate adenocarcinoma. These patients are often observed until radiographic progression of disease, at which point several treatment options are approved for treatment of metastatic CRPC (mCRPC).
Until recently, there were no regulatory-approved (ie, US Food and Drug Administration) treatment options for these patients. Earlier this year, 2 highly anticipated phase 3 randomized clinical trials reported on the efficacy of novel antiandrogen agents for the treatment of patients with nmCRPC. Among 1401 men, the PROSPER trial1 demonstrated significantly improved metastasis-free survival for patients receiving enzalutamide (36.6 months vs 14.7 months; hazard ratio [HR], 0.29; 95% CI, 0.24-0.35) compared with placebo. Similarly, among 1207 men, the SPARTAN trial2 reported improved metastasis-free survival for patients receiving apalutamide (40.5 months vs 16.2 months; HR, 0.28; 95% CI, 0.23-0.35) compared with placebo.2