Endometriosis (EM), affecting 6-15% of women in reproductive age, is defined as benign inflammatory disease caused by the ectopic endometrial gland and stroma outside of the uterus [1,2]. For patients with EM, persistent severe dysmenorrhea has been found to closely associated with coexistent adenomyosis (AM), a pathologic condition characterized by presence of ectopic endometrium within the myometrial layers that cause hyperplasia and hypertrophy of the surrounding myometrium[3]. AM and EM often coexist, sharing pathological mechanisms and clinical symptoms [4,5]. Note that the EM prevailed in 21.8-80.6% of patients with AM, and AM concomitantly existed in 79-91.1% of patients with EM [6], [7], [8]. Importantly, concurrent AM was found to positively correlate with higher pain scores after surgical excision compared with EM alone [9]. Moreover, coexistence of both pathological conditions is correlated with an increased risk of postoperative recurrence [10,11]. Ovarian endometriosis(OEM) is the most common type of endometriosis(17-44%). In our previous study [12], presence of adenomyosis was significantly higher in the OEM recurrence group. To reduce those patients with high recurrence risk, we focused on patients coexisted with OEM and AM in this study.

The resemblance between the two diseases goes beyond overlapping symptomatology, also stands in the medical treatment. The levonorgestrel-releasing intrauterine system (LNG-IUS), a T-shaped device, with a reservoir containing 52 mg of levonorgestrel, has been evaluated as long-term management for either EM or AM [13], [14], [15], [16]. Vercellini et al. found that LNG-IUS was associated with a reduced recurrence of dysmenorrhea and contributed to greater satisfaction about treatment in EM, comparing with expectant management after surgical excision [17]. A prospective study followed up symptomatic women with AM for 3 years and showed significant reduction in blood loss concomitant with notable pain relief [18]. Despite the work of LNG-IUS on either exclusively EM or AM was encouraging, its interaction on recurrence prevention in patients with coexistence EM and AM has been barely explored but urgently needed.

We conducted this retrospective study to evaluate the role of LNG-IUS in recurrence prevention for symptomatic patients affected by concomitant ovarian endometrima and diffuse AM. The therapeutic effect and associated risk factors of recurrence were also assessed.