Unfortunately prostate cancer may eventually stop responding to ADT and becomes hormone resistant. This is when the tumour no longer responds to the therapy and the prostate cancer cells carry on growing. This may occur as some cancer cells do not require testosterone to grow and are thus not affected by ADT and sometimes the cancer may change (mutate) so that the ADT which was initially sensitive to ADT, no longer is sensitive to its effects.

Over a period of 10 years of hormone treatment, it is expected that approximately 10% of men will have no evidence of prostate cancer regrowth.

If hormone therapy stops working and the PSA starts to rise, patients are left on their LHRH agonists and often started on an antiandrogen. The reason for that is that a proportion of the cancer cells are still thought to be sensitive to testosterone withdrawal. If one antiandrogen doesn’t work or initially works and then ceases to work then it can be substituted for another antiandrogen.

Other treatment options once hormone therapy stops working are localised radiotherapy to areas where the prostate cancer has spread and is causing symptoms, chemotherapy and experimental therapies.

Many new treatments are being discovered such as gene therapy, antiangiogenesis drugs, immunological approaches, and growth factor blocking drug and are providing promising new advances. If you are interested in being involved in a clinical trial with experimental therapies please discuss this with Dr Swindle.