Trial reportReproductive biology and endocrinology : RB&E2011
Letrozole and norethisterone acetate versus letrozole and triptorelin in the treatment of endometriosis related pain symptoms: a randomized controlled trial.
Trial report in Reproductive biology and endocrinology : RB&E, 2011. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 25 papers, 8 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
25 citing papers in PubMed, 8 syntheses or guidelines pooled it, 72 citations in OpenAlex.
- Clinical and endocrine effects of pharmacological therapy in endometriosis: a systematic review and meta-analysis.Frontiers in endocrinology · 2026Pooled it
- The natural evolution of untreated deep endometriosis and the effect of hormonal suppression: A systematic literature review and meta-analysis.Acta obstetricia et gynecologica Scandinavica · 2024Pooled it
- Gonadotropin-releasing hormone analogues for endometriosis.The Cochrane database of systematic reviews · 2023Pooled it
- A Systematic Review of Systematic Reviews on the Use of Aromatase Inhibitors for the Treatment of Endometriosis: The Evidence to Date.Drug design, development and therapy · 2023Pooled it
- Clinical practice guidelines for endometriosis in Japan (The 3rd edition).The journal of obstetrics and gynaecology research · 2022Guideline
- Is intracrinology of endometriosis relevant in clinical practice? A systematic review on estrogen metabolism.Frontiers in endocrinology · 2022Pooled it
- Is Scientific Medical Literature Related to Endometriosis Treatment Evidence-Based? A Systematic Review on Methodological Quality of Randomized Clinical Trials.Medicina (Kaunas, Lithuania) · 2019Pooled it
- Use of aromatase inhibitors to treat endometriosis-related pain symptoms: a systematic review.Reproductive biology and endocrinology : RB&E · 2011Pooled it
- Hormonal therapies for endometriosis-associated pain: inflammatory limitations and pharmacological challenges.Inflammopharmacology · 2026Review
- The interaction between inflammation and estrogen in adenomyosis : from molecular mechanisms to therapeutic strategies.Seminars in immunopathology · 2026Review
- The letrozole use in reproductive medicine: Beyond aromatase inhibition - a comprehensive review.Turkish journal of obstetrics and gynecology · 2026Article
- Dydrogesterone and Letrozole Combination for the Treatment of Endometriosis: A Mechanism-Based Therapeutic Approach.Obstetrics and gynecology international · 2026Article
- Article
- Review
- Clinical Efficacy, Pharmacokinetics, and Safety of the Available Medical Options in the Treatment of Endometriosis-Related Pelvic Pain: A Scoping Review.Pharmaceuticals (Basel, Switzerland) · 2023Review
- Evaluation of Different Doses of the Aromatase Inhibitor Letrozole for the Treatment of Ectopic Pregnancy and Its Effect on Villous Trophoblastic Tissue.Reproductive sciences (Thousand Oaks, Calif.) · 2022Article
- Management Challenges of Deep Infiltrating Endometriosis.International journal of fertility & sterility · 2021Review
- Article
- New insights on the pathogenesis of endometriosis and novel non-surgical therapiesJournal of the Turkish German Gynecological Association · 2018Article
- Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors at 3 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundWhen aromatase inhibitors are used to treat premenopausal women with endometriosis, additional drugs should be used to effectively down-regulate gonadal estrogen biosynthesis. This randomized prospective open-label study compared the efficacy in treating pain symptoms and the tolerability of letrozole combined with either norethisterone acetate or triptorelin.
methodsWomen with pain symptoms caused by rectovaginal endometriosis were treated with letrozole (2.5 mg/day) and were randomized to also receive either oral norethisterone acetate (2.5 mg/day; group N) or intramuscular injection of triptorelin (11.25 mg every 3 months; group T). The scheduled length of treatment was 6 months. A visual analogue scale and a multidimensional categorical rating scale were used to assess the severity of pain symptoms. The volume of the endometriotic nodules was estimated by ultrasonography using virtual organ computer-aided analysis. Adverse effects of treatment were recorded.
resultsA total of 35 women were randomized between the two treatment protocols. Significantly more patients in group N rated their treatment as satisfactory or very satisfactory (64.7%) as compared to group T (22.2%; p=0.028). The intensity of both non-menstrual pelvic pain and deep dyspareunia significantly decreased during treatment in both study groups, though no statistically meaningful difference between the two groups was apparent. Reduction in the volume of endometriotic nodules was significantly greater in group T than in group N. Interruption of treatment due to adverse effects significantly differed between the groups, with 8 women in group T (44.4%) and 1 woman in group N (5.9%) interrupting treatment (p=0.018). Similarly, 14 women included in group T (77.8%) and 6 women included in group N (35.3%) experienced adverse effects of treatment (p=0.018). During treatment, mineral bone density significantly decreased in group T but not in group N.
conclusionsAromatase inhibitors reduce the intensity of endometriosis-related pain symptoms. Combining letrozole with oral norethisterone acetate was associated with a lower incidence of adverse effects and a lower discontinuation rate than combining letrozole with triptorelin.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.