Endometriosis occurs when the tissue that lines the womb, the endometrium, grows outside the womb. It affects many millions of women worldwide. This tissue grows at the same time as the normal womb lining in response to our bodies hormones, but at the time of menstruation it has nowhere to go. The tissue is found almost anywhere in the body but is most commonly in the pelvic cavity, the area surrounding the womb, including the bowels, bladder and vagina. The break down of the tissue at the time of menstruation results in pain, inflammation, internal bleeding and sometimes infections and internal scarring. Usually the body would take care of the misplaced but in women with endometriosis it doesn't leading to symptoms of pain before and during periods, pain during sex, fatigue, painful urination and bowel movements before and during periods, infertility and gastrointestinal upset.
It is thought that this tissue settles in the pelvic cavity from a backwash effect up the fallopian tubes, or in farther reaches of the body, via the lymphatic system. It is most likely that all women suffer from this backwash, but that for some reason, in women with endometriosis, the immune system doesn't clear it away. Prevalence is increasing at the moment, possibly due to lower birth rates. Women used to spend a larger proportion of there reproductive lives pregnant. Toxins in our environment are also postulated as a cause for this rise.
Treatment used to involve the women becoming pregnant, at which time the tissue would shrivel, or surgery. Complications of surgery are common, often worsening symptoms, and indeed surgery is one postulated cause of endometriosis.
Drugs that suppress ovulation, such as the pill, are used but with mixed results.
The development of hormone analogues, drugs that mimic the action of natural hormones, led to an alternative treatment. Zoladex, (Gonaderelin) was originally developed to treat prostate cancer. It is an analogue of Gonadotrophin, the hormone that controls our sex hormones. Our monthly cycles are controlled by a complicated negative feedback system, basically increasing levels of one hormone cause the release of other hormones, which in turn stop the production of other hormones. Zoladex works by initially stimulating the ovaries and pituitaries, until they reach the switch off point, and hormone production stops. This is an artificial menopause, but it is completely reversible.
Zoladex is given by depot injections, which means one injection or implant each month for six months. At the end of this time the endometrial tissue should have shrunk away. Symptoms are often aggravated by the first injection because of the way it works. Inducing a false menopause induces menopausal side effects including hot flushes, sweating, and loss of periods, vaginal dryness, breast tenderness, sexual dysfunction, loss of libido and mood changes. Other side effects include aching muscles, water retention and aching joints. Patients may get a reaction at the injection site. The false menopause means that only one course of six months is usually given. More than this increases the risk of osteoporosis in later life.
T he discomfort of the treatment, and the severity of the side effects mean that Zoladex should only be used in cases where other treatment options have failed.