It has long been known that once prostate cancer develops, the male hormone testosterone, produced by the testicles, is closely involved in stimulating the cancer’s growth and spread. Earlier treatments for the disease often involved removing the testicles surgically to reduce testosterone production by the body. Now products are available that can be taken in the form of tablets or injections to suppress testosterone even more effectively. The process is known as hormone therapy.
Hormone therapy is often used to shrink the prostate and the tumour before commencing radiotherapy. It is now quite common for a course of hormone therapy to be administered after primary treatment by radiation or surgery, particularly if there is evidence that the tumour may have spread beyond the capsule (tissue immediately surrounding the prostate). There is emerging evidence that better outcomes are being achieved from these combined techniques.
If the prostate cancer has already spread to other organs or to bone at the time of diagnosis, hormone therapy becomes the primary method of treatment. Monthly or three monthly injections, possibly also accompanied by tablets, are used to try to reduce the PSA reading as close as possible to zero. Most advanced cancers respond well to hormone therapy for several years. Some doctors apply the therapy intermittently - six or twelve months on treatment then some months off - known as "pulsing". This gives the patient some respite from side effects and may extend the period of effective treatment, although this has not been proved.
The advantages of hormone therapy are that it is simple to administer. The disadvantages are the side effects, which can be distressing. They include hot flushes, loss of libido and erections, sweating, mood swings, disturbed sleep, loss of energy and personal motivation, body hair loss, bone loss, weight gain and breast development or tenderness. Unfortunately, most advanced cancers eventually become resistant to hormone therapy, after which the disease resumes its progress.