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.

Trial registration number: N/A.