BackgroundProstate cancer (PCa) accounts for 20% of all cancers in subjects over 50 years in Italy. The majority of patients with PCa present with localized disease at the time of diagnosis, but many patients develop recurrent metastatic disease after treatment with curative intent. Androgen deprivation therapy is the standard of care for metastatic PCa patients; unfortunately, most of them progress to castrate-resistant prostate cancer (CRPC) within 5 years. Metastatic CRPC (mCRPC) heavily affects patients in terms of quality of life, side effects, and survival, and greatly impacts economic costs. The approval of new effective agents in recent years, including cabazitaxel, abiraterone acetate, enzalutamide, and radium-223, has dramatically changed patient management.Materials and methodsHere, we aimed to estimate the current costs of illness of mCRPC in Italy. All patients affected by mCRPC and treated with a single agent in an annual time horizon were considered. Therefore, the analysis was not focused on the management pathway of single patients through different lines of treatment. Direct medical costs referred to therapy, adverse event management, and skeletal-related event management were analyzed. A bottom-up approach was used to estimate the resource consumption: through national guidelines and expert opinions, the mean cost per patient was estimated and then multiplied by the total number of patients diagnosed with mCRPC.ResultsDirect medical costs ranged from €196.5 million to €228.0 million, representing ~0.2% of the financing of the Italian National Health Service in 2016. The main cost driver was the cost of treatment, which represented more than 77% of the overall economic burden.ConclusionOur analysis, reflective of real clinical practice, shows for the first time the high economic cost of mCRPC in Italy.