June 20, 2008 — Aromatase inhibitors appear to be promising in alleviating pain, reducing lesion size and perhaps improving quality of life in women with painful endometriosis, researchers conclude based on a review of published studies.
Endometriosis is prevalent among women in the general population, affecting up to 50% of premenopausal women, and its symptoms such as chronic pelvic pain can be debilitating, note Dr. Sanjay Patwardhan and colleagues from Birmingham Women's Hospital, UK, in the June issue of BJOG: An International Journal of Obstetrics and Gynecology.
"Aromatase inhibitors inhibit aromatase p-450, which is the key enzyme for estrogen biosynthesis as it catalyses conversion of androstenedione and testosterone to estrone and estradiol (E2)," lead investigator Dr. Patwardhan explained in comments to Reuters Health. "Therefore, they provide an invaluable tool to treat estrogen-dependent conditions."
"These agents are well established in the management of breast cancer. However in benign gynecological conditions such as endometriosis and fibroids, their use is still in the context of research, which clearly reflects (the) dearth of primary data available for analysis," Dr. Patwardhan added.
Against this backdrop, the research team conducted a systematic review of eight studies in which the outcome of aromatase inhibitor therapy was evaluated in a total of 137 women with endometriosis.
In four case reports and three observational studies involving 40 women, they observed that aromatase inhibitors combined with progestogens, oral contraceptives, or gonadotrophin-releasing hormone (GnRH) analogues reduced average pain scores and lesion size and improved quality of life.
In the one randomized controlled trial involving 97 women, aromatase inhibitors in combination with GnRH analogues significantly improved pain and "multidimensional patient scores" compared with GnRH analogues alone (p < 0.0001 for both).
There was no significant decline in bone density at the hip or spine, as may have been expected, the investigators note. "As far as bone density changes are concerned, the available data reveal non-significant reductions," Dr. Patwardhan added.
"Treating chronic pain associated with endometriosis can be frustrating to both clinicians and patients, especially when it is recurrent or resistant to standard medical or surgical management," Dr. Patwardhan noted.
"Our systematic review provides the 'proof of principle' that aromatase inhibitors appear to be safe and effective in alleviating chronic pelvic pain associated with endometriosis, but it also exposes the limitations of the literature," he pointed out. "These clinical effects need confirmation by a prospective powerful, randomized controlled trial."
Reuters Health Information 2008. © 2008 Reuters Ltd.