MON-131 - Comparative Efficacy of Letrozole Versus Danazol for Pain Relief in Endometriosis: A Systematic Review and Meta-Analysis

Background:
Endometriosis is a chronic, estrogen-dependent gynecological condition affecting women of reproductive age and is commonly associated with persistent pelvic pain, dysmenorrhea, and reduced quality of life. Medical management primarily focuses on hormonal suppression to reduce ectopic endometrial activity and pain. Danazol, an androgenic agent, has historically been used for symptom control but is often limited by androgen-related adverse effects. Letrozole, an aromatase inhibitor, offers an alternative mechanism by inhibiting estrogen synthesis and has gained interest for the management of endometriosis-related pain. This systematic review and meta-analysis aimed to compare the efficacy of letrozole versus danazol in pain relief among patients with endometriosis.

Methods:
A comprehensive literature search of major electronic databases was conducted to identify comparative clinical studies evaluating letrozole versus danazol in women diagnosed with endometriosis. Pain relief was assessed using validated pain assessment scales. Pooled standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated using meta-analytic methods.

Results:
Three studies met the inclusion criteria, comprising a total of 450 patients, with 227 patients allocated to the letrozole group and 223 to the danazol group. The overall pooled mean age was 29.41 ± 5.48 years, with comparable baseline characteristics between the letrozole (29.47 ± 5.48 years) and danazol (29.36 ± 5.49 years) groups.Meta-analysis demonstrated that letrozole was associated with a significantly greater reduction in pain scores compared with danazol. The pooled effect size showed a substantial and statistically significant improvement in pain relief favoring letrozole (SMD −0.95; 95% CI −1.50 to −0.39). The consistency of baseline age across treatment groups supports the robustness of the comparative findings.

Conclusion:
Letrozole is significantly more effective than danazol in reducing pain among patients with endometriosis. These findings suggest that letrozole may be a superior therapeutic option for pain management in endometriosis, potentially offering improved efficacy with a more favorable clinical profile. Larger, well-designed randomized controlled trials are needed to confirm these results and to further evaluate long-term safety and reproductive outcomes.

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