Endometrial thickness in the evaluation of clinical response to medical treatment for deep infiltrating endometriosis: a retrospective study

Abstract

Purpose Deep infiltrating endometriosis (DIE) is associated with severe pelvic pain and functional impairment of bowel, urinary, and sexual functions. Though hormone therapy with progestins, either as single agents or combined with estrogens, is effective in managing symptoms, some patients may experience a suboptimal response. Endometrial thickness assessed by transvaginal ultrasound examination, reflecting the overall estrogen stimulation, may correlate with the clinical response to hormonal treatments. Methods A retrospective study was carried out on 61 women with DIE affecting the bowel or the recto-vaginal septum, undergoing hormone treatment. The symptoms of patients were evaluated at the baseline and after 12 months of therapy, calculating a global Visual Analogue Scale score (gVAS) encompassing dysmenorrhea, dyspareunia, chronic pelvic pain, dyschezia, abdominal pain and dysuria. Patients were divided into two subgroups using, as a calculated cut-off value, the mean endometrial thickness in our population at 12 months. The change in gVAS score during the 12 months of treatment was then compared between the two groups. Results Women with a thinner endometrium (< 3.3 mm) showed a better response to treatment in terms of symptoms control as compared to patients with a thicker endometrium (mean gVAS score reduction 9.2 ± 1.3 vs. 5.2 ± 1.3, p = 0.036). The correlation between endometrial thickness and symptomatic response was also confirmed (p = 0.041) on multivariate linear regression analysis including as covariates age, size of lesions of DIE, presence of uterine adenomyosis, ovarian endometriosis and type of medical treatment. Conclusion Endometrial thickness on ultrasound transvaginal examination is correlated with better response rates to hormone therapy in terms of symptoms control. A thinner endometrium, probably resulting from a more efficient suppression of estrogen stimulation, is associated with improved symptoms. These results may aid clinicians in monitoring and tailoring hormonal treatments during follow-up of women with symptomatic DIE.