Comparison of #Enzian classification and revised American Society for Reproductive Medicine stages for the description of disease extent in women with deep endometriosis

STUDY QUESTION How is endometriosis extent described by the #Enzian classification compared to the revised American Society for Reproductive Medicine (rASRM) stages in women undergoing radical surgery for deep endometriosis (DE)? SUMMARY ANSWER The prevalence and severity grade of endometriotic lesions and adhesions as well as the total number of #Enzian compartments affected by DE increase on average with increasing rASRM stage; however, DE lesions are also present in rASRM stages 1 and 2, leading to an underestimation of disease severity when using the rASRM classification. WHAT IS KNOWN ALREADY Endometriotic lesions can be accurately described regarding their localization and severity by sonography as well as during surgery using the recently updated #Enzian classification for endometriosis. STUDY DESIGN, SIZE, DURATION This was a prospective multicenter study including a total of 735 women between January 2020 and May 2021. PARTICIPANTS/MATERIALS, SETTING, METHODS Disease extent in women undergoing radical surgery for DE at tertiary referral centers for endometriosis was intraoperatively described using the #Enzian and the rASRM classification. MAIN RESULTS AND THE ROLE OF CHANCE A total of 735 women were included in the study. Out of 31 women with rASRM stage 1, which is defined as only minimal disease, 65% (i.e. 20 women) exhibited DE in #Enzian compartment B (uterosacral ligaments/parametria), 45% (14 women) exhibited DE in #Enzian compartment A (vagina/rectovaginal septum) and 26% (8 women) exhibited DE in #Enzian compartment C (rectum). On average, there was a progressive increase from rASRM stages 1-4 in the prevalence and severity grade of DE lesions (i.e. lesions in #Enzian compartments A, B, C, FB (urinary bladder), FU (ureters), FI (other intestinal locations), FO (other extragenital locations)), as well as of endometriotic lesions and adhesions in #Enzian compartments P (peritoneum), O (ovaries) and T (tubo-ovarian unit). In addition, the total number of #Enzian compartments affected by DE lesions on average progressively increased from rASRM stages 1-4, with a maximum of six affected compartments in rASRM stage 4 patients. LIMITATIONS, REASONS FOR CAUTION Interobserver variability may represent a possible limitation of this study. WIDER IMPLICATIONS OF THE FINDINGS The #Enzian classification includes the evaluation of DE in addition to the assessment of endometriotic lesions and adhesions of the ovaries and tubes and may therefore provide a comprehensive description of disease localization and extent in women with DE. STUDY FUNDING/COMPETING INTEREST(s) No funding was received for this study. All authors declare that they have no conflict of interest.