Prostate cancer cells need male hormones, called androgens, such as testosterone, to grow. Blocking the hormones with androgen deprivation therapy (also known as ADT or hormone therapy) can slow tumor growth or shrink the tumor. This is usually accomplished with drugs called luteinizing hormone-releasing hormone (LHRH) agonists, which prevent the testicles from making more testosterone. Although it has significant side effects and almost always loses its effectiveness over time, ADT is one of the most effective whole body therapies in existence — for any cancer.
Chemotherapy, or chemo, is an option for patients whose prostate cancer has spread outside of the prostate gland and when hormone therapy is no longer working. It is not expected to destroy all of the cancer cells, but it may shrink the cancer or slow its growth and reduce pain.
Chemotherapy uses anti-cancer drugs that are injected into a vein, injected into a muscle, or taken by mouth. These drugs kill cancer cells, but they also damage some normal cells. The doctor must maintain a delicate balance of chemo doses, making them high enough to kill the cancer cells but not high enough to destroy too many healthy cells.