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

Pain after oocyte retrieval in women with endometriosis undergoing fertility preservation or IVF

RESEARCH QUESTION

Do women with endometriosis undergoing oocyte retrieval for fertility preservation experience the same level of pain as women undergoing oocyte retrieval for IVF?

DESIGN

This retrospective cohort study included 796 cycles in women with endometriosis undergoing oocyte retrieval for fertility preservation (n = 401) or IVF (n = 395) between January 2020 and October 2022. Post-operative pain assessments were compared between the two groups using a numeric rating scale (NRS).

RESULTS

Women in the fertility preservation group were younger (32.1 ± 4.2 years versus 35.1 ± 4.1 years; P < 0.001), had a lower body mass index (22.8 ± 3.9 kg/m2 versus 24.6 ± 4.4 kg/m2; P < 0.001) and had a lower concentration of anti-Müllerian hormone (1.8 ± 1.5 ng/ml versus 2.15 ± 2.11 ng/ml; P = 0.026) in comparison with women in the IVF group. The oestrogen concentration on the day of ovulation trigger was higher in women in the fertility preservation group (2188 ± 1152 pg/ml versus 2081 ± 995 pg/ml; P = 0.004), and the prevalence rates of adenomyosis and digestive endometrial lesions were lower in women in the fertility preservation group (14% versus 29%, P < 0.001; 16% versus 25%, P = 0.003, respectively) compared with women in the IVF group. After oocyte puncture, more women in the fertility preservation group had an NRS pain score >3 (moderate to severe pain) compared with women in the IVF group (20% versus 14%; P = 0.018). The progestin-primed ovarian stimulation (PPOS) protocol was identified as an independent predictive factor of greater post-operative pain (adjusted OR 2.30, 95% CI 1.06-5.15; P = 0.039).

CONCLUSION

Women with endometriosis undergoing fertility preservation reported more intense post-operative pain in the recovery room than women undergoing IVF. The PPOS protocol was an independent risk factor of intense pain (NRS pain score >3) in women with endometriosis, but further studies are needed to confirm this result.

Investigational drugs for the treatment of dysmenorrhea

INTRODUCTION

Dysmenorrhea is the most common cause of gynecological pain among women that has considerable impact on quality of life and psychosocial wellbeing. Non-steroidal anti-inflammatory drugs (NSAIDs) and hormonal therapies are most commonly used to treat dysmenorrhea. However, given these drugs are often associated with bothersome side effects and are less effective when there is an underlying cause contributing to dysmenorrhea (e.g. endometriosis), a patient-centered approach to managing dysmenorrhea is important. Various new drugs are currently being investigated for the treatment of primary and secondary dysmenorrhea.

AREAS COVERED

This review provides an updated overview on new therapeutic targets and investigational drugs for the treatment of primary and secondary dysmenorrhea. The authors describe the clinical development and implications of these drugs.

EXPERT OPINION

Among the investigative drugs discussed in this review, anti-inflammatories show the most promising results for the treatment of dysmenorrhea. However, given some trials have considerable methodological limitations, many drugs cannot be currently recommended. Research focused on understanding the mechanisms involved in menstruation and its associated symptoms will be important to identify new therapeutic targets for dysmenorrhea. Further robust clinical trials are required to better understand the efficacy and safety of investigational drugs for treating primary and secondary dysmenorrhea.

A review of phase II and III drugs for the treatment and management of endometriosis

INTRODUCTION

Endometriosis is an estrogen-dependent disease that gives rise to pelvic pain and infertility. Although estroprogestins and progestins currently stand as the first-line treatments for this condition, demonstrating efficacy in two-thirds of patients, a significant portion of individuals experience only partial relief or symptom recurrence following the cessation of these therapies. The coexistence of superficial, deep endometriosis, and ovarian endometriomas, as three distinct phenotypes with unique pathogenetic and molecular characteristics, may elucidate the current heterogeneous biological response to available therapy.

AREAS COVERED

The objective of this review is to furnish the reader with a comprehensive summary pertaining to phase II-III hormonal treatments for endometriosis.

EXPERT OPINION

Ongoing research endeavors are directed toward the development of novel hormonal options for this benign yet debilitating disease. Among them, oral GnRH antagonists emerge as a noteworthy option, furnishing rapid therapeutic onset without an initial flare-up; these drugs facilitate partial or complete estrogen suppression, and promote prompt ovarian function recovery upon discontinuation, effectively surmounting the limitations associated with previously employed GnRH agonists. Limited evidence supports the use of selective estrogen and progesterone receptor modulators. Consequently, further extensive clinical research is imperative to garner a more profound understanding of innovative targets for novel hormonal options.

Aromatase enzyme: Paving the way for exploring aromatization for cardio-renal protection

Documented male-female differences in the risk of cardiovascular and chronic kidney diseases have been largely attributed to estrogens. The cardiovascular and renal protective effects of estrogens are mediated via the activation of estrogen receptors (ERα and ERβ) and G protein-coupled estrogen receptor, and involve interactions with the renin-angiotensin-aldosterone system. Aromatase, also called estrogen synthase, is a cytochrome P-450 enzyme that plays a pivotal role in the conversion of androgens into estrogens. Estrogens are biosynthesized in gonadal and extra-gonadal sites by the action of aromatase. Evidence suggests that aromatase inhibitors, which are used to treat high estrogen-related pathologies, are associated with the development of cardiovascular events. We review the potential role of aromatization in providing cardio-renal protection and highlight several meta-analysis studies on cardiovascular events associated with aromatase inhibitors. Overall, we present the potential of aromatase enzyme as a fundamental contributor to cardio-renal protection.

A Systematic Review of Systematic Reviews on the Use of Aromatase Inhibitors for the Treatment of Endometriosis: The Evidence to Date

Endometriosis is a chronic gynecologic condition that affects around 6-10% of reproductive age women. This clinical entity is characterized with pelvic pain, dysmenorrhea, dyspareunia, and infertility which are the most often presenting symptoms. Aromatase P450 is the key enzyme for ovarian estrogen biosynthesis and there is evidence that endometriotic lesions express aromatase and are able to synthesize their own estrogens. Aromatase inhibitors (AIs) are potent drugs that suppress the estrogen synthesis via suppression of aromatase. We performed a systematic review of systematic reviews and narrative reviews on the use of aromatase inhibitors in the medical management of endometriosis. We searched: PubMed (1950-2022), Google Scholar (2004-2022), Cochrane Library (2010-2022) and Researchgate (2010-2022). The search included the following medical subject headings (MeSH) or keywords: "Aromatase Inhibitors" AND "Endometriosis" AND "Systematic reviews" OR "Systematic review" AND "Reviews" OR "Reviews" AND "Endometriosis". The electronic database search yielded initially 12,106 studies from the different databases. Further assessment of the studies resulted in exclusion of (n = 12,015) studies due to duplicates and irrelevance; Finally, 24 studies were selected for inclusion, 5 were Systematic reviews and 19 were Narrative reviews. The 5 systematic reviews were assessed by AMSTAR-2 criteria and were found to have low quality. Narrative reviews were assessed with SANRA criteria and were found to have high-quality aromatase inhibitors are potent drugs that can manage the endometriosis-related symptoms in cases where initial medical management has failed to show positive results. However, their use is limited by the adverse effects that are linked with menopausal symptoms. aromatase inhibitors can be administered as an alternative treatment in patients. Future studies with randomized design are required to reach safer conclusions and further investigation. These studies should define the therapeutic dose, new add-back therapy modalities. Future directions should examine the most-appropriate way of administration and the duration of therapy.

The latest advances in the pharmacological management of endometriosis

INTRODUCTION

Endometriosis is a benign disease, characterized by a wide range of symptoms and different degrees of severity, which is why therapy should be individually adapted to the patient's needs. Over the years, a lot of research has gone into finding new therapeutic approaches for this enigmatic disease.

AREAS COVERED

This review presents the latest advances in pharmacological management of endometriosis and is solely focused on studies published from 2010 to 2021.

EXPERT OPINION

Clinicians and researchers are constantly searching for new therapeutic strategies for endometriosis patients. As there are well-established treatments, however, any new medication should fulfill at least one of the three criteria: increased efficacy, comparable efficacy but a better safety profile, or treatments that have a lack of accompanying contraceptive effects that are seen in most endometriosis treatments. While some new substances show promising results, further studies are needed to demonstrate the fulfillment of one of the above-mentioned criteria.

Oleuropein suppresses endometriosis progression and improves the fertility of mice with endometriosis

BACKGROUND

Endometriosis is an estrogen-dependent inflammatory reproductive disease. Therefore, systematic estrogen depletion and anti-inflammatory drugs are the current treatment for endometriosis. However, current endometriosis treatments have low efficacy and cause adverse effects in endometriosis patients. Consequently, alternative endometriosis treatments targeting endometriosis-specific factors are in demand. In this context, ERβ was selected as a druggable target for endometriosis due to its critical role in progression. Therefore, selective targeting of ERβ without inhibiting ERα activity would be a new paradigm for endometriosis treatment to overcome the low efficacy and adverse effects of hormonal endometriosis therapy.

METHODS

Cell-based ERβ and ERα activity assay systems were employed to define a selective ERβ-inhibiting chemical product from a library of natural products. A surgically induced endometriosis mouse model was used to determine whether an ERβ inhibitory drug suppressed endometriosis progression. Mice with endometriosis were randomly separated and then orally treated with vehicle or 25 mg/kg oleuropein (once a day for 21 days), an ERβ inhibitory drug. The volume of endometriotic lesions or luciferase activity of endometriotic lesions was examined to define the growth of ectopic lesions in mice with endometriosis. The metabolite and levels of metabolic enzymes of the liver and kidney were determined in the serum of female mice treated with vehicle and oleuropein (25 mg/kg, once a day for 21 days) to define the toxicity of oleuropein. The in vitro decidualization assay was conducted with normal human endometrial stromal cells and endometriotic stromal cells to determine whether oleuropein overcomes decidualization in endometriosis patients. The pregnancy rate and pup numbers of C57BL/6 J female mice with endometriosis treated with vehicle or oleuropein (n = 10/group) were determined after mating with male mice. The cytokine profile in endometriotic lesions treated with vehicle and oleuropein (25 mg/kg) was determined with a Mouse Cytokine Array Kit.

RESULTS

Among natural products, oleuropein selectively inhibited ERβ but not ERα activity in vitro. Oleuropein treatment inhibited the nuclear localization of ERβ in human endometrial cells upon estradiol treatment. Oleuropein (25 mg/kg) treatment suppressed the growth of mouse (6.6-fold) and human (sixfold) ectopic lesions in mice with endometriosis compared to the vehicle by inhibiting proliferation and activating apoptosis in endometriotic lesions. Oleuropein treatment did not cause reproductive toxicity in female mice. Additionally, mice with endometriosis subjected to oleuropein treatment had a higher pregnancy rate (100%) than vehicle-treated mice (70%). Furthermore, oleuropein treatment partially recovered the decidualization impact of human endometriotic stromal cells from endometriotic lesions compared to the vehicle. Oleuropein-treated mice with endometriosis exhibited significantly lower levels of cytokines directly regulated by ERβ in ectopic lesions than vehicle-treated mice, illustrating the improvement in the hyperinflammatory state of mice with endometriosis.

CONCLUSIONS

Oleuropein is a promising and novel nutraceutical product for nonhormonal therapy of endometriosis because it selectively inhibits ERβ, but not ERα, to suppress endometriosis progression and improve the fertility of mice with endometriosis.

Hormonal treatments for endometriosis: The endocrine background

Endometriosis is a benign uterine disorder characterized by menstrual pain and infertility, deeply affecting women's health. It is a chronic disease and requires a long term management. Hormonal drugs are currently the most used for the medical treatment and are based on the endocrine pathogenetic aspects. Estrogen-dependency and progesterone-resistance are the key events which cause the ectopic implantation of endometrial cells, decreasing apoptosis and increasing oxidative stress, inflammation and neuroangiogenesis. Endometriotic cells express AMH, TGF-related growth factors (inhibin, activin, follistatin) CRH and stress related peptides. Endocrine and inflammatory changes explain pain and infertility, and the systemic comorbidities described in these patients, such as autoimmune (thyroiditis, arthritis, allergies), inflammatory (gastrointestinal/urinary diseases) and mental health disorders.The hormonal treatment of endometriosis aims to block of menstruation through an inhibition of hypothalamus-pituitary-ovary axis or by causing a pseudodecidualization with consequent amenorrhea, impairing the progression of endometriotic implants. GnRH agonists and antagonists are effective on endometriosis by acting on pituitary-ovarian function. Progestins are mostly used for long term treatments (dienogest, NETA, MPA) and act on multiple sites of action. Combined oral contraceptives are also used for reducing endometriosis symptoms by inhibiting ovarian function. Clinical trials are currently going on selective progesterone receptor modulators, selective estrogen receptor modulators and aromatase inhibitors. Nowadays, all these hormonal drugs are considered the first-line treatment for women with endometriosis to improve their symptoms, to postpone surgery or to prevent post-surgical disease recurrence. This review aims to provide a comprehensive state-of-the-art on the current and future hormonal treatments for endometriosis, exploring the endocrine background of the disease.

ESHRE guideline: endometriosis

STUDY QUESTION

How should endometriosis be diagnosed and managed based on the best available evidence from published literature?

SUMMARY ANSWER

The current guideline provides 109 recommendations on diagnosis, treatments for pain and infertility, management of disease recurrence, asymptomatic or extrapelvic disease, endometriosis in adolescents and postmenopausal women, prevention and the association with cancer.

WHAT IS KNOWN ALREADY

Endometriosis is a chronic condition with a plethora of presentations in terms of not only the occurrence of lesions, but also the presence of signs and symptoms. The most important symptoms include pain and infertility.

STUDY DESIGN SIZE DURATION

The guideline was developed according to the structured methodology for development of ESHRE guidelines. After formulation of key questions by a group of experts, literature searches and assessments were performed. Papers published up to 1 December 2020 and written in English were included in the literature review.

PARTICIPANTS/MATERIALS SETTING METHODS

Based on the collected evidence, recommendations were formulated and discussed within specialist subgroups and then presented to the core guideline development group (GDG) until consensus was reached. A stakeholder review was organized after finalization of the draft. The final version was approved by the GDG and the ESHRE Executive Committee.

MAIN RESULTS AND THE ROLE OF CHANCE

This guideline aims to help clinicians to apply best care for women with endometriosis. Although studies mostly focus on women of reproductive age, the guideline also addresses endometriosis in adolescents and postmenopausal women. The guideline outlines the diagnostic process for endometriosis, which challenges laparoscopy and histology as gold standard diagnostic tests. The options for treatment of endometriosis-associated pain symptoms include analgesics, medical treatments and surgery. Non-pharmacological treatments are also discussed. For management of endometriosis-associated infertility, surgical treatment and/or medically assisted reproduction are feasible. While most of the more recent studies confirm previous ESHRE recommendations, there are five topics in which significant changes to recommendations were required and changes in clinical practice are to be expected.

LIMITATIONS REASONS FOR CAUTION

The guideline describes different management options but, based on existing evidence, no firm recommendations could be formulated on the most appropriate treatments. Also, for specific clinical issues, such as asymptomatic endometriosis or extrapelvic endometriosis, the evidence is too scarce to make evidence-based recommendations.

WIDER IMPLICATIONS OF THE FINDINGS

The guideline provides clinicians with clear advice on best practice in endometriosis care, based on the best evidence currently available. In addition, a list of research recommendations is provided to stimulate further studies in endometriosis.

STUDY FUNDING/COMPETING INTERESTS

The guideline was developed and funded by ESHRE, covering expenses associated with the guideline meetings, with the literature searches and with the dissemination of the guideline. The guideline group members did not receive payments. C.M.B. reports grants from Bayer Healthcare and the European Commission; Participation on a Data Safety Monitoring Board or Advisory Board with ObsEva (Data Safety Monitoring Group) and Myovant (Scientific Advisory Group). A.B. reports grants from FEMaLE executive board member and European Commission Horizon 2020 grant; consulting fees from Ethicon Endo Surgery, Medtronic; honoraria for lectures from Ethicon; and support for meeting attendance from Gedeon Richter; A.H. reports grants from MRC, NIHR, CSO, Roche Diagnostics, Astra Zeneca, Ferring; Consulting fees from Roche Diagnostics, Nordic Pharma, Chugai and Benevolent Al Bio Limited all paid to the institution; a pending patent on Serum endometriosis biomarker; he is also Chair of TSC for STOP-OHSS and CERM trials. O.H. reports consulting fees and speaker's fees from Gedeon Richter and Bayer AG; support for attending meetings from Gedeon-Richter, and leadership roles at the Finnish Society for Obstetrics and Gynecology and the Nordic federation of the societies of obstetrics and gynecology. L.K. reports consulting fees from Gedeon Richter, AstraZeneca, Novartis, Dr KADE/Besins, Palleos Healthcare, Roche, Mithra; honoraria for lectures from Gedeon Richter, AstraZeneca, Novartis, Dr KADE/Besins, Palleos Healthcare, Roche, Mithra; support for attending meetings from Gedeon Richter, AstraZeneca, Novartis, Dr KADE/Besins, Palleos Healthcare, Roche, Mithra; he also has a leadership role in the German Society of Gynecological Endocrinology (DGGEF). M.K. reports grants from French Foundation for Medical Research (FRM), Australian Ministry of Health, Medical Research Future Fund and French National Cancer Institute; support for meeting attendance from European Society for Gynaecological Endoscopy (ESGE), European Congress on Endometriosis (EEC) and ESHRE; She is an advisory Board Member, FEMaLe Project (Finding Endometriosis Using Machine Learning), Scientific Committee Chair for the French Foundation for Research on Endometriosis and Scientific Committee Chair for the ComPaRe-Endometriosis cohort. A.N. reports grants from Merck SA and Ferring; speaker fees from Merck SA and Ferring; support for meeting attendance from Merck SA; Participation on a Data Safety Monitoring Board or Advisory Board with Nordic Pharma and Merck SA; she also is a board member of medical advisory board, Endometriosis Society, the Netherlands (patients advocacy group) and an executive board member of the World Endometriosis Society. E.S. reports grants from National Institute for Health Research UK, Rosetrees Trust, Barts and the London Charity; Royalties from De Gruyter (book editor); consulting fees from Hologic; speakers fees from Hologic, Johnson & Johnson, Medtronic, Intuitive, Olympus and Karl Storz; Participation in the Medicines for Women's Health Expert Advisory Group with Medicines and Healthcare Products Regulatory Agency (MHRA); he is also Ambassador for the World Endometriosis Society. C.T. reports grants from Merck SA; Consulting fees from Gedeon Richter, Nordic Pharma and Merck SA; speaker fees from Merck SA, all paid to the institution; and support for meeting attendance from Ferring, Gedeon Richter and Merck SA. The other authors have no conflicts of interest to declare.

DISCLAIMER

This guideline represents the views of ESHRE, which were achieved after careful consideration of the scientific evidence available at the time of preparation. In the absence of scientific evidence on certain aspects, a consensus between the relevant ESHRE stakeholders has been obtained. Adherence to these clinical practice guidelines does not guarantee a successful or specific outcome, nor does it establish a standard of care. Clinical practice guidelines do not replace the need for application of clinical judgement to each individual presentation, nor variations based on locality and facility type. ESHRE makes no warranty, express or implied, regarding the clinical practice guidelines and specifically excludes any warranties of merchantability and fitness for a particular use or purpose (Full disclaimer available at www.eshre.eu/guidelines.).

The Effect of Letrozole Combined with Dydrogesterone for Endometriosis in China: A Meta-Analysis

Purpose

To discuss the effects of dydrogesterone combined with letrozole on the effectiveness, sex hormone levels, and serological indicators in patients with endometriosis. This study is registered with PROSPERO (CRD42020213172).

Methods

We searched relevant randomized controlled trials (RCTs) through PubMed, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, and VIP Database. The standardized mean differences (SMDs), the mean differences (MDs), or odds ratios (ORs) with their 95% confidence intervals (95% CIs) were computed to be outcome indicators, including total effectiveness, Vascular Endothelial Growth Factor (VEGF) level, Carbohydrate Antigen 125 (CA125) level, Follicle-Stimulating Hormone (FSH) level, Luteinizing Hormone (LH) level, estrogen (E2) level, progesterone (P) level, interleukin-6 (IL-6) level, and tumor necrosis factor-a (TNF-a) level.

Results

A total of 19 RCTs involving 1,591 patients were included in this study. Our results showed that letrozole combined with dydrogesterone can significantly reduce the levels of VEGF (SMD -2.23, 95% CI -2.39 to -2.07; p < 0.00001), CA125 (MD -10.53, 95% CI -11.19 to -9.88; p < 0.00001), E2 (SMD -1.64, 95% CI -1.81 to -1.47; p < 0.00001), P (MD -5.11, 95% CI -6.26 to -3.96; p < 0.00001), IL-6 (MD -4.41, 95% CI -5.16 to -3.67; p < 0.00001), and TNF-a (MD -5.67, 95% CI -6.34 to -5.00; p < 0.00001) in patients with endometriosis compared with the control group. In addition, the results indicated that total effectiveness was significantly higher in the experiment group (OR 6.21, 95% CI 4.17 to 9.24; p < 0.00001) compared to the control. However, there was no significant difference between FSH and LH levels in both groups (p > 0.05).

Conclusion

This combination therapy can effectively decrease the levels of VEGF, CA125, E2, P, IL-6, and TNF-a and increase the total effectiveness when comparing with the control group.

Breakthrough Bleeding in Transgender and Gender Diverse Adolescents and Young Adults on Long-Term Testosterone

STUDY OBJECTIVE

Amenorrhea is a goal of many transgender and gender diverse adolescent and young adult (TGD AYA) patients on testosterone gender-affirming hormone therapy (T-GAHT). Breakthrough bleeding can contribute to worsening gender dysphoria. Our objective was to evaluate breakthrough bleeding in TGD AYA on T-GAHT.

DESIGN

Institutional review board-approved retrospective cohort.

SETTING

Tertiary-care children's hospital.

PARTICIPANTS

TGD AYA on T-GAHT >1 year.

INTERVENTIONS

None; observational.

MAIN OUTCOME MEASURES

Presence of, and risk factors for, breakthrough bleeding.

RESULTS

Of the 232 patients who met inclusion criteria, one-fourth (n = 58) had 1 or more episodes of breakthrough bleeding, defined as bleeding after more than 1 year on T-GAHT. In comparing patients with breakthrough bleeding to those without, there were no significant differences between age of initiation, body mass index (BMI), race/ethnicity, testosterone type used, use of additional menstrual suppression, serum testosterone, or estradiol levels. Patients with breakthrough bleeding patients were on T-GAHT longer (37.3 ± 17.0 vs 28.5 ± 14.6 months, P < .001) and were more likely to have endometriosis (P = .049). Breakthrough bleeding began at a mean of 24.3 ± 17.2 months after T-GAHT initiation. Of those with breakthrough bleeding, 46 (79.3%) had no known cause, 10 (17.2%) bled only with missed T-GAHT doses, and 2 (3.4%) bled only when withdrawing from concomitant menstrual suppression. No breakthrough bleeding management method was found to be superior.

CONCLUSION

Breakthrough bleeding is relatively common (25%) on T-GAHT despite early amenorrhea. Most cases do not have an identifiable cause. Our data did not show superiority of any 1 method for managing breakthrough bleeding on T-GAHT.

Pentoxifylline for the treatment of endometriosis-associated pain and infertility

BACKGROUND

Endometriosis is a chronic inflammatory condition that occurs during the reproductive years. It is characterised by endometrium-like tissue developing outside the uterine cavity. This endometriotic tissue development is dependent on oestrogen produced primarily by the ovaries and partially by the endometriotic tissue itself, therefore traditional management has focused on ovarian suppression. In this review we considered the role of modulation of the immune system as an alternative approach. This is an update of a Cochrane Review previously published in 2012.

OBJECTIVES

To determine the effectiveness and safety of pentoxifylline in the management of endometriosis.  SEARCH METHODS: We searched the Cochrane Gynaecology and Fertility (CGF) Group Trials Register, CENTRAL, MEDLINE, Embase, PsycINFO, and AMED on 16 December 2020, together with reference checking and contact with study authors and experts in the field to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing pentoxifylline with placebo or no treatment, other medical treatment, or surgery in women with endometriosis. The primary outcomes were live birth rate and overall pain (as measured by a visual analogue scale (VAS) of pain, other validated scales, or dichotomous outcomes) per woman randomised. Secondary outcomes included clinical pregnancy rate, miscarriage rate, rate of recurrence, and adverse events resulting from the pentoxifylline intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies against the inclusion criteria, extracted data, and assessed risk of bias, consulting a third review author where required. We contacted study authors as needed. We analysed dichotomous outcomes using Mantel-Haenszel risk ratios (RRs), 95% confidence intervals (CIs), and a fixed-effect model. For small numbers of events, we used a Peto odds ratio (OR) with 95% CI instead. We analysed continuous outcomes using the mean difference (MD) between groups presented with 95% CIs. We used the I2 statistic to evaluate heterogeneity amongst studies. We employed the GRADE approach to assess the quality of the evidence.

MAIN RESULTS

We included five parallel-design RCTs involving a total of 415 women. We included one additional RCT in this update. Three studies did not specify details relating to allocation concealment, and two studies were not blinded. There were also considerable loss to follow-up, with four studies not conducting intention-to-treat analysis. We judged the quality of the evidence as very low. Pentoxifylline versus placebo No trials reported on our primary outcomes of live birth rate and overall pain. We are uncertain as to whether pentoxifylline treatment affects clinical pregnancy rate when compared to placebo (RR 1.38, 95% CI 0.91 to 2.10; 3 RCTs, n = 285; I2 = 0%; very low-quality evidence). The evidence suggests that if the clinical pregnancy rate with placebo is estimated to be 20%, then the rate with pentoxifylline is estimated as between 18% and 43%. We are also uncertain as to whether pentoxifylline affects the recurrence rate of endometriosis (RR 0.84, 95% CI 0.30 to 2.36; 1 RCT, n = 121; very low-quality evidence) or miscarriage rate (Peto OR 1.99, 95% CI 0.20 to 19.37; 2 RCTs, n = 164; I2 = 0%; very low-quality evidence). No trials reported on the effect of pentoxifylline on improvement of endometriosis-related symptoms other than pain or adverse events. Pentoxifylline versus no treatment No trials reported on live birth rate. We are uncertain as to whether pentoxifylline treatment affects overall pain when compared to no treatment at one month (MD -0.36, 95% CI -2.12 to 1.40; 1 RCT, n = 34; very low-quality evidence), two months (MD -1.25, 95% CI  -2.67 to 0.17; 1 RCT, n = 34; very low-quality evidence), or three months (MD -1.60, 95% CI -3.32 to 0.12; 1 RCT, n = 34; very low-quality evidence). No trials reported on adverse events caused by pentoxifylline or any of our other secondary outcomes. Pentoxifylline versus other medical therapies One study (n = 83) compared pentoxifylline to the combined oral contraceptive pill after laparoscopic surgery to treat endometriosis, but could not be included in the meta-analysis as it was unclear if the data were presented as +/- standard deviation and what the duration of treatment was. No trials reported on adverse events caused by pentoxifylline or any of our other secondary outcomes. Pentoxifylline versus conservative surgical treatment  No study reported on this comparison.

AUTHORS' CONCLUSIONS

No studies reported on our primary outcome of live birth rate. Due to the very limited evidence, we are uncertain of the effects of pentoxifylline on clinical pregnancy rate, miscarriage rate, or overall pain. There is currently insufficient evidence to support the use of pentoxifylline in the management of women with endometriosis with respect to subfertility and pain relief outcomes.

Novel therapeutic targets to improve IVF outcomes in endometriosis patients: a review and future prospects

BACKGROUND

Patients with endometriosis often experience infertility and have poor IVF outcomes, with low fertilization and pregnancy rates. Although many theories have tried to explain the mechanisms underlying infertility in these patients, none of them is conclusive.

OBJECTIVE AND RATIONALE

In this review, we discuss the pathologic mechanisms through which endometriosis likely leads to infertility along with the therapeutic options used to date to treat endometriosis-related infertility and, thereby, to improve IVF outcomes in patients with endometriosis.

SEARCH METHODS

We performed a comprehensive literature search of clinical outcomes in endometriosis and the molecular mechanisms contributing to oocyte quality using the PubMed database to identify human and animal studies published from 1992 until September 2020. In total, 123 manuscripts were included.

OUTCOMES

While some theories propose that endometriosis patients may have fertility problems as a result of decreased endometrial receptivity, others reinforce the idea that infertility could be associated with oocyte alterations and lower implantation rates. Single-cell RNA sequencing of oocytes from patients with endometriosis has identified dysregulated mechanisms involved in steroid metabolism and biosynthesis, response to oxidative stress and cell cycle regulation. Dysregulation of these mechanisms could result in the poor IVF outcomes observed in patients with endometriosis. Further, impaired steroidogenesis may directly affect oocyte and embryo quality. Increased oxidative stress in patients with endometriosis also has a detrimental effect on the follicular microenvironment, inducing cell cycle dysregulation in oocytes, poor oocyte quality, and infertility. Moreover, granulosa cells in the context of endometriosis undergo increased apoptosis and have an altered cell cycle that could adversely affect folliculogenesis, oocyte and embryo quality, and IVF outcomes. Endometriosis is also associated with inflammatory damage and impaired angiogenesis, which could be directly correlated with poor IVF outcomes. While therapeutic options using GnRH analogues, progestins and aromatase inhibitors do not improve endometriosis-related infertility, anti-inflammatory agents and antioxidant supplementation could improve oocyte quality as well as implantation and clinical pregnancy rates in patients with endometriosis.

WIDER IMPLICATIONS

Endometriosis is a heterogeneous disease whose pathogenesis is complex and could affect fertility by altering a collection of molecular mechanisms in oocytes. Thus, a single model is not sufficient to describe endometriosis-related infertility. Dysregulation of steroidogenesis, oxidative stress, cell cycle progression, inflammation and angiogenesis in the follicular environment and oocytes in individuals with endometriosis are all possible contributors to endometriosis-related infertility. Therefore, treatments targeting these mechanisms could be therapeutic alternatives to improve IVF outcomes for these patients.

Pathophysiological Basis of Endometriosis-Linked Stress Associated with Pain and Infertility: A Conceptual Review

Women with endometriosis are often under stress due to the associated pain, infertility, inflammation-related and other comorbidities including cancer. Additionally, these women are also under stress due to taboos, myths, inter-personal troubles surrounding infertility and pain of the disease as well as due to frequent incidences of missed diagnosis and treatment recurrence. Often these women suffer from frustration and loss of valuable time in the prime phase of life. All these complexities integral to endometriosis posit a hyperstructure of integrative stress physiology with overt differentials in effective allostatic state in women with disease compared with disease-free women. In the present review, we aim to critically examine various aspects of pathophysiological basis of stress surrounding endometriosis with special emphasis on pain and subfertility that are known to affect the overall health and quality of life of women with the disease and promising pathophysiological basis for its effective management.

Administration of aromatase inhibitor MPV-2213ad to blue fox vixens (Vulpes lagopus) as a model for contraception in female dogs

The interest in non-surgical approaches to contraception and fertility control in female dogs has increased in recent years. In this study the effect of an aromatase inhibitor (finrozole) was evaluated in fur production animals, farmed blue fox vixens, as a model for contraception in bitches. A total of 80 vixens were divided into 4 groups, receiving orally placebo (A) or finrozole 0.5 mg/kg (B), 3.5 mg/kg (C) or 24.5 mg/kg (D) for 21 consecutive days beginning in the pre-ovulatory period of heat. Monitoring of the vixens included clinical signs of heat, measurement of vaginal electrical resistance (VER) as well as oestradiol and progesterone concentrations in plasma. The approximate relation of the start of treatment to ovulation varied from 11 days before to one day after ovulation provided that the LH peak occurred 0.5-2 days before the VER peak and ovulation was then estimated to occur 2 days after the LH peak. Seventy vixens were artificially inseminated within 8 h after a 50 Ω decline in vaginal electrical resistance was detected. Ten vixens were not inseminated. Pregnancy was confirmed by transabdominal ultrasound examination and birth of cubs was recorded. The pregnancy rates in the groups were 89.5% (A), 81.3% (B), 55.6% (C) and 52.9% (D). The average number of live born pups in the four groups was 9.4 (A), 7.0 (B), 5.8 (C), and 3.8 (D), respectively. No deleterious effects (for instance malformations) of finrozole on pups could be verified. The administration of finrozole did not have a significant effect on oestradiol parameters and VER values in vixens. Progesterone values were significantly higher in treatment groups compared with the placebo group. The results indicate that pregnancy could be avoided by finrozole provided that doses of ≥3.5 mg/kg were used and the treatment was initiated at least four days before the day of artificial insemination. This corresponds with two to six days before ovulation provided that the LH peak occurred 0.5-2 days before the VER peak and that ovulation then occurred in average 2 days after the LH peak.

The effects of letrozole on women with endometriosis undergoing ovarian stimulation for in vitro fertilization

This study aimed to analyze the effects of a new protocol with letrozole on the outcomes of in vitro fertilization (IVF) cycles in women with endometriosis. This retrospective cohort study was conducted for women diagnosed with endometriosis undergoing IVF from an infertility clinic. A new protocol, combination therapy with letrozole and gonadotropin, was used from August 2016 to January 2018 ('protocol 1', n = 38). From March 2014 to July 2016, conventional IVF with gonadotropin was administered ('protocol 2', n = 26). Age and ovarian reserve were comparable between the two groups. The patients who received protocol 1 resulted in a significantly lower peak estradiol level in IVF compared with those received protocol 2 (722 ± 1076 pg/mL versus 2168 ± 1521 pg/mL, p < .001). The length of stimulation, the total dose of gonadotropin, number of oocytes retrieved, fertilization rates, and number of embryos obtained were similar between the two groups. The mean percentage of mature oocytes was lower (69.9 ± 23.7% versus 80.2 ± 21.0%, p = .029) in patients with protocol 1. While maintaining low estrogen levels, the combination therapy with letrozole and gonadotropin produce similar oocyte and embryo yield to the conventional IVF protocol in women with endometriosis.

Effect of local aromatase inhibition in endometriosis using a new chick embryo chorioallantoic membrane model

Endometriosis is an oestrogen‐dependent, inflammation‐driven gynaecologic disorder causing severe disability. Endometriosis implants are characterized by unbalanced local oestrogen metabolism leading to hyperoestrogenism and aromatase up‐regulation is one of main mechanism involved. Aromatase inhibitors such as letrozole or anastrozole use in young women are associated with severely side effects limiting their long‐term clinical use. An endometriosis‐targeted inhibition of local aromatase could be a viable alternative, although the role of the local inhibition of this enzyme is still unclear. Using a new chick embryo allantoic membrane (CAM) model incorporating xenografted human endometriosis cyst, we showed that topical treatment with anastrozole reduced lesion size, although oestrogens produced by CAM female embryo blunted this effect. Xenografted human endometriosis CAM is a new efficient model for the screening of new drugs targeting endometriosis tissue.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

New insights on the pathogenesis of endometriosis and novel non-surgical therapies

Endometriosis is a disease of theories, but none has succeeded to explain the whole picture. Most widely available drugs for endometriosis aim to relieve symptoms and improve fertility. Unfortunately, many short and long-term side-effects are associated with the treatments. To overcome this problem, researchers have developed many novel therapeutic agents, including non-invasive technique. We aim to provide new insights on pathogenesis model and novel non-surgical treatments for endometriosis, including drugs already available in the market and also drugs which are still under research. Seven novel treatment modalities are recognized, namely dienogest, aromatase inhibitor (AI), gonadotrophine-releasing hormone (GnRH) antagonist, anti tumor necrosing factor (TNF)-α, selective estrogen receptor modulator (SERM), selective progesterone receptor modulator (SPRM), and high-intensity focused ultrasound (HIFU). Dienogest, AI, and GnRH antagonists are effective novel treatments with good tolerance and safety. SERM and SPRM show inconsistent results, while anti-TNF-α is still in the animal experimental stage. HIFU is a potential futuristic treatment. However, it is still a long way until this technology is truly applicable.

Aromatase as a target for treating endometriosis

Endometriosis is a common gynecological disease that causes various clinical symptoms, such as chronic pelvic pain, dysmenorrhea and infertility, seriously affecting women's health and their quality of life. The symptoms and endometriotic lesions are relieved, in many cases, after menopause, when estrogen levels are lowered. Therefore, endometriosis is considered to be estrogen-dependent. Aromatase, the enzyme responsible for the last step of estrogen biosynthesis converting testosterone and androgen to estrogen, was previously reported to be more abundant in endometriotic tissues than in the normal endometrium, leading to an increased local estrogen concentration. Therefore, aromatase is considered a key therapeutic target for regulating local estrogen biosynthesis in endometriosis. A more complete understanding of the mechanisms that modulate aromatase and its activity is required to develop novel estrogen-targeted therapies for endometriosis. In this review article, we outline the current understanding of the pathological processes involved in estrogen production in endometriosis and propose novel strategies to treat this disorder.

Aromatase inhibitors in the treatment of endometriosis

Endometriosis is a chronic inflammatory condition in which foci of endometrial tissue grow outside of the uterine cavity. Endometriosis was estimated to affect 176 million women of childbearing potential all over the world in 2010. The presence of extrauterine endometrial tissue is associated with pain and infertility. Typical symptoms of endometriosis include dysmenorrhoea, dyspareunia, heavy menstrual periods (menorrhagia), pelvic pain that is not related to menstrual cycles, dysuria, and chronic fatigue. Medical treatments for endometriosis include combined oral contraceptive pills, danazol, gestrinone, medroxyprogesterone acetate, and gonadotropin-releasing hormone agonists (aGnRHs). A new class of medications called aromatase inhibitors has been identified in recent years as potential therapeutic agents for endometriosis. This article provides general information about aromatase inhibitors, their use in gynaecology, and their adverse effects. In particular, the paper discusses the use of aromatase inhibitors in the treatment of endometriosis in postmenopausal women. Unlike oral contraceptives, gestagens, aGnRHs, and danazol, which suppress ovarian oestrogen synthesis, aromatase inhibitors inhibit mainly extra-ovarian synthesis of oestrogens. Therefore, the use of aromatase inhibitors seems to be particularly relevant in older patients, as most of the body's oestrogen is produced outside the ovaries after menopause. The paper discusses also the use of aromatase inhibitors in the treatment of pain associated with endometriosis and infertility caused by endometriosis.

Innovations in classical hormonal targets for endometriosis

Endometriosis is a chronic disease of unknown etiology that affects approximately 10% of women in reproductive age. Several evidences show that endometriosis lesions are associated to hormonal imbalance, including estrogen synthesis, metabolism and responsiveness and progesterone resistance. These hormonal alterations influence the ability of endometrial cells to proliferate, migrate and to infiltrate the mesothelium, causing inflammation, pain and infertility. Hormonal imbalance in endometriosis represents also a target for treatment. We provide an overview on therapeutic strategies based on innovations of classical hormonal mechanisms involved in the development of endometriosis lesions. The development phase of new molecules targeting these pathways is also discussed. Endometriosis is a chronic disease involving young women and additional biological targets of estrogen and progesterone pharmacological manipulation (brain, bone and cardiovascular tissue) need to be carefully considered in order to improve and overcome current limits of long-term medical management of endometriosis.

Medical treatment for adenomyosis and/or adenomyoma

Uterine adenomyosis and/or adenomyoma is characterized by the presence of heterotopic endometrial glands and stroma within the myometrium, >2.5 mm in depth in the myometrium or more than one microscopic field at 10 times magnification from the endometrium-myometrium junction, and a variable degree of adjacent myometrial hyperplasia, causing globular and cystic enlargement of the myometrium, with some cysts filled with extravasated, hemolyzed red blood cells, and siderophages. Hysterectomy is a "gold standard" and definitive therapy for uterine adenomyosis, and many cases of adenomyosis have been diagnosed by pathological review retrospectively. As such, the diagnosis of adenomyosis is difficult, and this subsequently results in difficulty in the management of these patients, especially those who are symptomatic but have a strong desire to preserve their uterus. In our previous review, we found that the use of uterine-sparing surgery in the management of uterine adenomyosis and/or adenomyoma is still controversial, although some data support its feasibility. Conservative treatment is still needed in the group of patients that requires preservation of fertility and improvement of quality of life. However, studies focusing on the topic of medical treatment for adenomyosis are rare. In this article, current knowledge regarding the use of medical therapy for uterine adenomyosis, partly based on the understanding of endometriosis, is reviewed.

Dual suppression of estrogenic and inflammatory activities for targeting of endometriosis

Estrogenic and inflammatory components play key roles in a broad range of diseases including endometriosis, a common estrogen-dependent gynecological disorder in which endometrial tissue creates inflammatory lesions at extrauterine sites, causing pelvic pain and reduced fertility. Current medical therapies focus primarily on reducing systemic levels of estrogens, but these are of limited effectiveness and have considerable side effects. We developed estrogen receptor (ER) ligands, chloroindazole (CLI) and oxabicycloheptene sulfonate (OBHS), which showed strong ER-dependent anti-inflammatory activity in a preclinical model of endometriosis that recapitulates the estrogen dependence and inflammatory responses of the disease in immunocompetent mice and in primary human endometriotic stromal cells in culture. Estrogen-dependent phenomena, including cell proliferation, cyst formation, vascularization, and lesion growth, were all arrested by CLI or OBHS, which prevented lesion expansion and also elicited regression of established lesions, suppressed inflammation, angiogenesis, and neurogenesis in the lesions, and interrupted crosstalk between lesion cells and infiltrating macrophages. Studies in ERα or ERβ knockout mice indicated that ERα is the major mediator of OBHS effectiveness and ERβ is dominant in CLI actions, implying involvement of both ERs in endometriosis. Neither ligand altered estrous cycling or fertility at doses that were effective for suppression of endometriosis. Hence, CLI and OBHS are able to restrain endometriosis by dual suppression of the estrogen-inflammatory axis. Our findings suggest that these compounds have the desired characteristics of preventive and therapeutic agents for clinical endometriosis and possibly other estrogen-driven and inflammation-promoted disorders.

Characterization of anastrozole effects, delivered by an intravaginal ring in cynomolgus monkeys

STUDY QUESTION

Is it feasible to deliver anastrozole (ATZ), an aromatase inhibitor (AI), by a vaginal polymer-based drug delivery system in the cynomolgus monkey (Macaca fascicularis) to describe the pharmacokinetic profile?

SUMMARY ANSWER

The present study showed the effective release of ATZ into the systemic circulation from intravaginal rings in cynomolgus monkeys.

WHAT IS KNOWN ALREADY

ATZ is a marketed drug with well documented pharmacological and safety profiles for oral administration. Aromatase is the key enzyme catalyzing estrogen biosynthesis and is overexpressed in endometriotic lesions. AIs show therapeutic efficacy in endometriosis in exploratory clinical trials.

STUDY DESIGN, SIZE, DURATION

The pharmacokinetics of the in vivo release and the pharmacodynamic activity of ATZ released by intravaginal rings (IVR) were investigated in healthy cycling female cynomolgus monkeys in three different dose groups (n = 5) for one menstrual cycle.

PARTICIPANTS/MATERIALS, SETTING, METHODS

IVRs for the cynomolgus monkey, releasing three different doses of ATZ were designed and tested for in vitro/in vivo release for up to 42 days. For pharmacokinetic and pharmacodynamic evaluation, plasma samples were taken once daily from Day 1 to 3 and then every third day until menses occurred (17-42 days).

MAIN RESULTS AND THE ROLE OF CHANCE

ATZ was shown to be compatible with the IVR drug delivery system. An average in vivo release of 277 µg/day/animal of ATZ for one menstrual cycle was effective in causing a decrease of systemic estradiol (E₂) levels by ∼30% without inducing counter regulation such as the elevation of FSH or the formation of ovarian cysts.

LIMITATIONS, REASONS FOR CAUTION

The study was limited to three dose groups in which only the highest dose decreased the E₂ level. Hence, additional research with IVRs releasing higher amounts of ATZ is required to define the threshold for an ATZ-dependent ovarian stimulation in cynomolgus monkeys.

WIDER IMPLICATIONS OF THE FINDINGS

The release rate administered from IVRs is sufficient and in a range that supports feasibility of IVR administration of ATZ as a new approach for long-term therapy of estrogen-dependent diseases such as endometriosis in human.

Potential role of aromatase inhibitors in the treatment of endometriosis

Endometriosis is an estrogen-dependent chronic inflammatory disease affecting 5%–10% of reproductive-age women, with a prevalence of 5%–50% in infertile women and >33% of women with chronic pelvic pain. Third-generation aromatase inhibitors (AIs) are approved adjuvants for the treatment of estrogen receptor-positive breast cancer. Molecular studies have revealed the presence of aromatase P450, the key enzyme in the biosynthesis of ovarian estradiol, inside the endometriotic tissue, indicating local synthesis of estradiol. Thereby, AIs represent an appealing medical option for the management of different aspects of this enigmatic disease, especially pelvic pain and infertility. Accordingly, this review aims to evaluate the potential role of AIs in the treatment of endometriosis-associated symptoms, mainly pain and infertility. Notably, several studies have demonstrated that the combination of AIs with conventional therapy as oral contraceptive pills, progestins, or gonadotropin-releasing hormone analogs can be used to control endometriosis-associated pain and pain recurrence in premenopausal women, particularly those with pain due to rectovaginal endometriosis refractory to other medical or surgical treatment. Some case reports have shown promising results in the treatment of postmenopausal endometriosis as first-line treatment, when surgery is contraindicated, or as second-line treatment in the case of postoperative recurrence. Third-generation AIs, especially letrozole, have challenged clomiphene citrate as an ovulation-induction agent in patients with polycystic ovary syndrome and in cases of unexplained infertility. However, few studies are available regarding the use of AIs to treat endometriosis-associated infertility. Therefore, larger multicenter randomized trials using AIs for the treatment of endometriosis-associated infertility are needed to clarify its effect. The safety of AIs for ovulation induction or superovulation has generated a lively discussion. Data from recent retrospective and prospective studies have supported its safety.

Management of thoracic endometriosis: single institution experience

OBJECTIVE

Thoracic endometriosis is a relatively rare type of endometriosis and includes catamenial pneumothorax, hemothorax and hemoptysis, and presence of intrathoracic endometriotic nodules. We want to clarify and resume the most appropriate management of this pathology.

STUDY DESIGN

We retrospectively reviewed all the cases of thoracic endometriosis diagnosed and followed up in our Unit from 2005 to 2013. This search revealed five women, with a mean age of 34.5 (26-44). Four had previous history of endometriosis or severe dysmenorrhea. One patient complained of chronic shoulder pain with diaphragmatic implants, another one presented catamenial hemoptysis, and three women suffered from catamenial pneumothorax, with right-side preference.

RESULTS

Three patients underwent surgery and all of them were treated with GnRH agonists at least during 6 month referring improvement in symptoms. After 1-8 years follow-up, all these patients remain asymptomatic.

CONCLUSION

The optimal management of thoracic endometriosis needs further evaluation but the combined approach by hormonal therapy and surgery could be the best option.

ESHRE guideline: management of women with endometriosis

STUDY QUESTION

What is the optimal management of women with endometriosis based on the best available evidence in the literature?

SUMMARY ANSWER

Using the structured methodology of the Manual for ESHRE Guideline Development, 83 recommendations were formulated that answered the 22 key questions on optimal management of women with endometriosis.

WHAT IS KNOWN ALREADY

The European Society of Human Reproduction and Embryology (ESHRE) guideline for the diagnosis and treatment of endometriosis (2005) has been a reference point for best clinical care in endometriosis for years, but this guideline was in need of updating.

STUDY DESIGN, SIZE, DURATION

This guideline was produced by a group of experts in the field using the methodology of the Manual for ESHRE Guideline Development, including a thorough systematic search of the literature, quality assessment of the included papers up to January 2012 and consensus within the guideline group on all recommendations. To ensure input from women with endometriosis, a patient representative was part of the guideline development group. In addition, patient and additional clinical input was collected during the scoping and review phase of the guideline.

PARTICIPANTS/MATERIALS, SETTING, METHODS

NA.

MAIN RESULTS AND THE ROLE OF CHANCE

The guideline provides 83 recommendations on diagnosis of endometriosis and on the treatment of endometriosis-associated pain and infertility, on the management of women in whom the disease is found incidentally (without pain or infertility), on prevention of recurrence of disease and/or painful symptoms, on treatment of menopausal symptoms in patients with a history of endometriosis and on the possible association of endometriosis and malignancy.

LIMITATIONS, REASONS FOR CAUTION

We identified several areas in care of women with endometriosis for which robust evidence is lacking. These areas were addressed by formulating good practice points (GPP), based on the expert opinion of the guideline group members.

WIDER IMPLICATIONS OF THE FINDINGS

Since 32 out of the 83 recommendations for the management of women with endometriosis could not be based on high level evidence and therefore were GPP, the guideline group formulated research recommendations to guide future research with the aim of increasing the body of evidence.

STUDY FUNDING/COMPETING INTEREST(S)

The guideline was developed and funded by ESHRE, covering expenses associated with the guideline meetings, with the literature searches and with the implementation of the guideline. The guideline group members did not receive payment. All guideline group members disclosed any relevant conflicts of interest (see Conflicts of interest).

TRIAL REGISTRATION NUMBER

NA.