Low-dose letrozole – an effective option for women with symptomatic adenomyosis awaiting IVF: a pilot randomized controlled trial

Can low-dose letrozole reduce dysmenorrhoea, menorrhagia and sonographic features in symptomatic women with adenomyosis awaiting IVF?This was a longitudinal randomized prospective pilot study to explore the effectiveness of low-dose letrozole and compare it with a gonadotropin releasing hormone (GnRH) agonist in reducing dysmenorrhoea, menorrhagia and sonographic features in symptomatic women with adenomyosis awaiting IVF. The women were treated for 3 months, either with the GnRH agonist goserelin 3.6 mg/month (n = 77) or the aromatase inhibitor letrozole 2.5 mg three times weekly (n = 79). Dysmenorrhoea and menorrhagia were evaluated at randomization and followed up monthly using a visual analogue score (VAS) and pictorial blood loss assessment chart (PBAC), respectively. A quantitative scoring method was used to assess the improvement of sonographic features after 3 months of treatment.Both groups reported a marked improvement in symptoms after 3 months of treatment. In both the letrozole and GnRH agonist groups, VAS and PBAC scores decreased significantly over the 3 months (letrozole: P = 0.0001 and P = 0.0001 for VAS and PBAC, respectively; GnRH agonist: P = 0.0001 and P = 0.0001 for VAS and PBAC, respectively). Participants on letrozole had regular menstruation cycles, while most of the women who received the GnRH agonist were amenorrhoeic, with only four women reporting mild bleeding. Haemoglobin concentrations also improved after both treatments (letrozole P = 0.0001, GnRH agonist P = 0.0001). A quantitative assessment of sonographic features showed significant improvements following both treatments (diffuse adenomyosis of the myometrium: letrozole P = 0.015, GnRH agonist P = 0.039; diffuse adenomyosis of the junctional zone: letrozole P = 0.025, GnRH agonist P = 0.001). Women with adenomyoma also responded well to both therapies (letrozole P = 0.049, GnRH agonist P = 0.024), whereas the letrozole group responded comparatively better in focal adenomyosis when the outer myometrium was involved (letrozole P < 0.001, GnRH agonist P = 0.26). No noticeable side effects were observed in women receiving letrozole therapy. Additionally, letrozole therapy was found to be more cost-effective than GnRH agonist treatment.Low-dose letrozole treatment is a low-cost alternative to a GnRH agonist, with comparable effects in improving the symptoms and sonographic features of adenomyosis in women awaiting IVF.