The prostate gland and prostate cancer are under the influence of testosterone, the male sex hormone, which drives the tumour to grow and spread. By blocking the body’s production of testosterone, or preventing its action, hormone therapy may greatly reduce the cancer’s capacity to grow. When the cancer has spread away from the prostate, usually going to either the lymph nodes or bones, hormone therapy can be effective at shrinking the tumour and reducing the side effects of the disease. It will often keep the cancer in check for a number of years. This can be assessed by keeping an eye on the PSA blood test.
Hormone therapy is also often used in conjunction with external beam radiotherapy as for some cancers it improves their response to the radiotherapy. In these circumstances, patients typically have hormone therapy for 3 months prior to the radiotherapy starting and may continue with the medication for between three months and two years.
There are two basic types of hormone therapy. Anti-androgens, delivered daily in tablet form, do not stop the production of testosterone, but block its effects on the prostate. An LH-RH analogue comes in the form of a slowly dissolving pellet that is usually injected every month or three months to prevent the production of testosterone by the testicles (Prostap and Zoladex are drugs commonly used for this purpose). The injection is straightforward and can be given at a GP’s surgery or is sometimes self-administered. It is common for anti-androgens to be prescribed for a short period before Prostap or Zoladex are injected.
Possible side effects from the treatment with hormones include weight gain, hot flushes, tiredness, mood change, reduced sex drive and loss of erection. Some patients may experience tenderness in the breast area and in rare cases some degree of breast enlargement. It is important to discuss the relative effectiveness of different hormone treatments and the likelihood of possible side effects with your consultant or clinical nurse specialist.