Biological characteristics related to treatment effects of the levonorgestrel-releasing intrauterine system on adenomyosis-associated dysmenorrhoea.

Research Question: Are there correlations between the biological expression of steroid receptors and the extent of fibrosis in adenomyotic lesions, and the treatment effectiveness of the levonorgestrel-releasing intrauterine system (LNG-IUS) on alleviation of adenomyosis-associated dysmenorrhoea.

Design: In this retrospective cohort study, 125 women with adenomyosis who underwent hysterectomy were screened. Tissue samples were collected from 41 patients who had undergone LNG-IUS treatment prior to surgery, and these patients were further categorized into the treatment effective group (n = 18) and the treatment failure group (n = 23) according to their self-reported relief from dysmenorrhoea after 6 months of treatment. Oestrogen receptor-α (ER-α) and progesterone receptor expression, and the extent of fibrosis in the adenomyotic lesions were measured using immunohistochemistry and Masson's trichrome staining, respectively.

Results: Patients in the treatment failure group demonstrated lower expression of ER-α and progesterone receptors, and more pronounced fibrosis in the stroma of adenomyotic lesions compared with patients in the treatment effective group. In the glandular epithelium of lesions, ER-α expression was reduced significantly in the treatment failure group, whereas no notable difference in the expression of progesterone receptors was observed. Notably, the staining intensity of ER-α in the stroma of lesions was found to have the strongest positive correlation with the degree of symptom alleviation for dysmenorrhoea (r = 0.703, P < 0.001), with an area under the curve of 0.894 for prediction.

Conclusions: The reduced expression of steroid receptors in adenomyotic lesions, especially ER-α in the stroma, was associated with increased likelihood of treatment failure of LNG-IUS for alleviation of dysmenorrhoea.