L26/P-371 Improvement in endometriosis symptoms post-surgery in a multi-center cohort study using the #ENZIAN classification

Abstract Study question Do the cardinal symptoms of endometriosis improve after surgery and is the change dependent on localization and extent of lesions according to the #ENZIAN classification? Summary answer Mean VAS scores improved at 6 months and remained stable at 12 months for all #ENZIAN subtypes of endometriosis: P only, POT, ABC and FA. What is known already Endometriosis is associated with dysmenorrhea, dyspareunia, dyschezia und dysuria, with poor correlation between symptoms and specific localization of lesions according to the ASRM and #ENZIAN classifications. Laparoscopic excision of endometriosis significantly reduces symptoms in the majority of patients, but few studies have systematically evaluated the correlation of localization of lesions to post-operative outcomes. Previous studies have grouped patients according to stage but not focused on particular anatomical regions nor manifestations such as the rectovaginal septum, adenomyosis or superficial endometriosis. Forming exclusive groups according to the #ENZIAN classification compartments could shed light on which manifestations are associated with best post-operative improvement. Study design, size, duration This prospective multi-center cohort study included 683 women with surgically confirmed endometriosis who underwent laparoscopic surgery by an expert endometriosis surgeon between September 2022 and January 2024. Participants were recruited pre-operatively at 18 Endometriosis Centers in Austria, Germany and Switzerland, all certified by the Scientific Endometriosis Foundation (SEF) and European Endometriosis League (EEL). Patients were followed for up to 12 months after surgery. Participants/materials, setting, methods Cardinal symptoms of endometriosis (severe dysmenorrhea, dyspareunia, dyschezia und dysuria) were assessed by self-reported VAS prior to, 6 and 12 months post-operatively, using the modified AGEM Questionnaire. Changes in symptoms reported by VAS scores were evaluated for the time points and compared according to #ENZIAN compartments. Analysis included general estimation equations and linear mixed models. In subgroup analyses, we investigated whether associations were modified by completeness of resection, hormone intake, and occurrence of pregnancy. Main results and the role of chance Overall, we saw a significant reduction in the probability of having each of the four symptoms of endometriosis, as well as a significant decline in the VAS scores at 6 months post-surgery (all comparisons p ≤ 0.005), which continued to be stable up to 12 months. All manifestations of endometriosis, peritoneal only (P), peritoneal, ovarian and tubal (POT), deep infiltrating (Compartments A/B/C) showed similar trajectories of improvement in VAS at 6 and 12 months (all between-group comparisons p > 0.05), although absolute VAS scores differed. For example, women with adenomyosis only (FA) with severe dysmenorrhea, dyspareunia and dyschezia benefited less from surgery and had higher VAS scores at 6 and 12 months than the other groups. Interestingly, dysuria and dyschezia improved post-operatively not only in those with involvement of P or A/B/C compartments, but also in women with FA only (p < 0.001). None of the potential effect modifiers (complete lesion resection (79%), pregnancy (9.7%), hormonal use (58.3%)) appeared to affect the outcomes, but these results may be limited by relatively small number of subjects in some of the subgroups. Limitations, reasons for caution The sample size limited statistical power for some subgroup analyses. The indication for surgery was made by the treating surgeon at each certified endometriosis center. The study sample may not be representative of women undergoing surgery by general gynecologists and at non-specialized centers. Wider implications of the findings Women with all manifestations of endometriosis show similar trajectories of improvement following surgery. Those with adenomyosis report highest post-operative VAS scores and should be counseled about the limitations of surgical outcomes. The results of our study can aid in counseling patients about post-operative outcomes and in managing their expectations. Trial registration number No