Use of aromatase inhibitors to treat endometriosis-related pain symptoms: a systematic review

Abstract

This systematic review aims to assess the efficacy of aromatase inhibitors (AIs) in treating pain symptoms caused by endometriosis. A comprehensive literature search was conducted to identify all the published studies evaluating the efficacy of type II nonsteroidal aromatase inhibitors (anastrozole and letrozole) in treating endometriosis-related pain symptoms. The MEDLINE, EMBASE, PubMed, and SCOPUS databases and the Cochrane System Reviews were searched up to October 2010. This review comprises of the results of 10 publications fitting the inclusion criteria; these studies included a total of 251 women. Five studies were prospective non-comparative, four were randomized controlled trials (RCTs) and one was a prospective patient preference trial. Seven studies examined the efficacy of AIs in improving endometriosis-related pain symptoms, whilst three RCTs investigated the use of AIs as post-operative therapy in preventing the recurrence of pain symptoms after surgery for endometriosis. All the observational studies demonstrated that AIs combined with either progestogens or oral contraceptive pill reduce the severity of pain symptoms and improve quality of life. One patient preference study demonstrated that letrozole combined with norethisterone acetate is more effective in reducing pain and deep dyspareunia than norethisterone acetate alone. However, letrozole causes a higher incidence of adverse effects and does not improve patients' satisfaction or influence recurrence of symptoms after discontinuation of treatment. A RCT showed that combining letrozole with norethisterone acetate causes a lower incidence of adverse effects and lower discontinuation rate than combining letrozole with triptorelin. Two RCTs demonstrated that, after surgical treatment of endometriosis, the administration of AIs combined with gonadotropin releasing hormone analogue for 6 months reduces the risk of endometriosis recurrence when compared with gonadotropin releasing hormone analogue alone. In conclusion, AIs effectively reduce the severity of endometriosis-related pain symptoms. Since endometriosis is a chronic disease, future investigations should clarify whether the long-term administration of AIs is superior to currently available endocrine therapies in terms of improvement of pain, adverse effects and patient satisfaction.

Chronic Pelvic Pain

“…[55][56][57] For deeply infiltrating endometriosis, aromatase inhibitors with norethindrone may work similarly without as significant hypoestrogenic effects. 58,59 Surgery Two basic surgical approaches have been used to treat chronic pelvic pain: removing pelvic organs and treating visible disease while leaving the pelvic organs in place. The use of both approaches is guided by clinical experience, because high-quality scientific data regarding the role of surgery in pelvic pain are sparse.…”

Letrozole and Curcumin Loaded-PLGA Nanoparticles: A Therapeutic Strategy for Endometriosis

“…Unfortunately, hypoestrogenism induces many unpleasant side-effects such as hot flashes, uterine spotting and decrease in bone mineral density [21]. As mentioned earlier, aromatase inhibitors such as letrozole are being proposed as the new medical therapy for endometriosis [22]; however, well-designed clinical studies to test the efficacy of these drugs on an adequate sample size are still lacking [23].…”

“…It is also concluded that the NPs are biocompatible and do not possess any significant toxicity in vitro (Figure 8). Moreover, Cur and Let are proven non-toxic drugs having undergone rigorous human clinical trials [9,22]. For selecting the ideal dose, 40 mg/kg of Let-Cur-NPs was administered in mice every day intra peritoneally and was studied for 7 consecutive days.…”

Involvement of Prostaglandins in the Pathophysiology of Endometriosis

“…This systematic study shows that the AIs, letrozole and anastrozole, are effective in treating pain symptoms; when withdrawn symptoms reappear, but they cannot be used for a long term therapy because of the adverse effects these compounds have on bone density (Ferrero et al, 2011). Endometriosis patients need chronic treatment, and this could be achieved combining AIs with a hormonal therapy to reduce the loss of bone density (Ferrero et al, 2011).…”