Metastatic castration-resistant prostate cancer (mCRPC) is a form of prostate cancer that has spread beyond the prostate and continues to progress despite low levels of testosterone, typically after the patient has undergone androgen deprivation therapy (ADT) through either surgical or chemical castration. In this stage, the cancer becomes resistant to traditional hormone therapy, meaning it no longer responds to testosterone suppression. Common sites of metastasis include the bones (most frequently), lymph nodes, liver, and lungs.
Metastatic high-risk castration-sensitive prostate cancer (mCSPC or mHSPC) refers to prostate cancer that has also spread beyond the prostate but still responds to hormonal therapy. “Castration-sensitive” indicates that the cancer is still responsive to testosterone-lowering treatments. Patients with high-risk disease typically have high-volume metastases (such as visceral involvement or four or more bone lesions), elevated PSA levels, or a high Gleason score (≥8).