Metastasis—also referred to as “metastatic cancer”—is the medical term for cancer that has spread to a part of the body outside its origin. With regards to prostate cancer, the terms metastatic prostate cancer, advanced prostate cancer, and stage IV (4) prostate cancer generally refer to cancer that has spread beyond the lymph nodes and tissues immediately surrounding the prostate.
How and Where Metastases Form
Metastasis most commonly occurs when cancer cells break away from the main tumor and are circulated throughout the body via the bloodstream or lymphatic system. During this process, these cancer cells can collect and grow in different parts of the body, forming metastases. Several factors influence the likelihood of metastasis in prostate cancer, including the cancer’s aggressiveness, indicated by its Gleason score, and the point at which treatment begins.
Theoretically, any cancer can spread to any part of the body. In reality, certain types of cancer tend to spread to specific places. Prostate cancer most commonly spreads to the bones, followed by the lymph nodes, lungs, liver, and brain. Regardless of where metastases form, the type of cancer remains the same. Prostate cancer that has metastasized to the bones is still prostate cancer, not bone cancer.