This will be a national observational, non-randomised, multicentre study, conducted in France.

Patients will be recruited in routine clinical practice by office- or hospital-based urology and/or oncology specialists when a first line treatment for their castrate resistant prostate cancer is initiated. The decision to treat patients with either agent preceding study enrolment will be left to the investigator's decision, per routine clinical practice. The nature of treatment and clinical care of patients will not be influenced by their participation in the study. All patients meeting the study criteria who visit the study physician will be consecutively invited to participate in the study to minimise recruitment bias. All medications administered will be collected. This is a non-interventional study. The investigators are free to choose products, and modalities of administration in accordance with the local Summary of Product Characteristics Therefore, the decision to prescribe one of these therapies must be made prior to and independently from the decision to enrol patients in this non interventional study.

Potential DDI will be identified using electronic screening methods (Micromedex Software and Theriaque Software).

This design will enable assessment of treatment and subsequent outcomes based on local standards, and is likely to encompass a wider range of therapeutic decisions compared with the stricter, defined limits on therapy required by investigational study protocols. Decisions and outcomes made in real-world conditions are likely to be more widely applicable to clinical practice than those from interventional studies.

Following French regulation there is no need for an approval of ethic committee for this type of observational study.

• Males aged ≥18 years;
• Histologically or cytologically confirmed diagnosis of adenocarcinoma of the prostate
• For patients with a nmCRPC, documented castration resistance with progression of prostate cancer on androgen deprivation therapy (ADT) (surgical or chemical);
• Initiation of first- line systemic therapy (with abiraterone, apalutamide, darolutamide, docetaxel or enzalutamide) for a non metastatic castrate-resistant or a metastatic castrate naïve prostate cancer according to the approved labels and current guidelines. The metastatic status is based on conventional imaging (CT scan, bone scan).

Patients are not eligible if they are receiving an investigational treatment for prostate cancer of any kind.

Patients with a non metastatic castration-resistant or a metastatic castrate naïve prostate cancer, with a minimum of 100 patients with a non metastatic castrate-resistant prostate cancer.