The Safety and Effectiveness of Surgery With or Without Raloxifene for the Treatment of Pelvic Pain Caused by Endometriosis

Overview

Many women with lower abdominal pain have endometriosis. Endometriosis is a condition in which the lining of the uterus (endometrium) is found outside of the uterus. The diagnosis of endometriosis is usually made at surgery. The treatment of endometriosis includes medical and surgical approaches alone or in combination. The hormone estrogen stimulates the growth of the endometrium and may also stimulate the growth of endometriosis. Medical therapies that act to decrease the level of estrogen can reduce the amount of endometriosis and pain. When therapies are discontinued, symptoms often return. In addition, medical treatment for endometriosis is expensive and is often associated with weak bones (osteoporosis) and hot flashes as a result of low levels of estrogen. Surgical treatment is removal or destruction of the endometriosis tissue. Studies show the pain from endometriosis is relieved longer with tissue removal than with destruction. This study was developed to see if surgery followed by daily doses of Raloxifene (Evista) is effective in reducing pain, for a longer time than surgery in combination with a placebo (inactive "sugar pill") treatment. Raloxifene acts like estrogens in some tissues and not like estrogens in others. Postmenopausal women receiving Raloxifene for the prevention of osteoporosis had an increase in bone density and an improvement of their blood lipids (fat content in the blood). However, unlike estrogen, Raloxifene does not promote the growth of breast tissue or the uterus. If Raloxifene blocks estrogen action in the lining of the uterus (endometrium) of reproductive age women, as it does in post-menopausal women, it may also limit the growth of endometriosis and prevent the return of pain.

Many women with pelvic pain have endometriosis, a condition in which tissue from the uterine lining (endometrium) is also outside the uterus. Endometriosis pain often returns after medical treatment is stopped. Surgical therapies have had varied success in reducing pain, with laparoscopic excision of implants one of the most effective methods. Raloxifene (Evista (Trademark), Lilly), has been approved by the Food and Drug Administration for use in preventing bone loss in postmenopausal women. This compound has effects that are both similar to and different from those of the hormone estrogen. Unlike estrogen, raloxifene does not stimulate growth of the uterus or breast tissue in post-menopausal women. If raloxifene blocks estrogen action in the lining of the uterus (or endometrium) of reproductive age women, as it does in postmenopausal women, it may also limit growth of endometriosis and prevent the return of pain. This phase II randomized placebo-controlled study evaluates whether surgery followed by daily administration of raloxifene for six months reduces pain for a longer time than surgery alone.