Converting Enzian into AAGL2021: A Step Toward Unified Staging

A successful conversion between two classification systems is feasible, with only a few exceptions.

Key Points

Highlights:

• The #Enzian classification offers detailed coding of endometriosis but lacks a simple staging system.
• This study proposes and evaluates a new 4-stage scoring model based on #Enzian, aligned with the AAGL2021 classification.

Importance:

• A uniform and intuitive endometriosis classification system is essential for international standardization, surgical planning, and patient communication.
• The complexity of the #Enzian system can be a barrier to use for non-experts and patients.
• A 4-stage model could maintain anatomical detail while increasing clinical accessibility.

What's done here:

• A feasibility study with 222 laparoscopic endometriosis patients from a European tertiary center, developed a point-based scoring model to convert #Enzian compartments into a 4-stage system.
• Points were derived from AAGL2021 scoring and refined through expert consensus.
• The resulting #Enzian 4-stage model was retrospectively compared with AAGL2021 stages.

Key Results:

• The overall stage distributions between the new #Enzian and AAGL2021 were closely aligned: Stage 1: 43% (#Enzian) vs 44% (AAGL2021); Stage 2: 20% vs 24%; Stage 3: 11% vs 9% and  Stage 4: 27% vs 21%.
• Differences appeared in stage composition, especially for deep lesions (e.g., Compartment B) and adenomyosis — not accounted for in AAGL2021.
• Sankey diagram showed how cases shift between stages when switching systems.
• The model simplifies #Enzian into a staging system while preserving its broader anatomical coverage.

Lay Summary

The revised American Society of Reproductive Medicine (rASRM) is the most widely used classification for endometriosis. This classification is easy to use but has some limitations, especially in describing deep endometriotic lesions and pain severity. On the other hand, the Enzian classification can code peritoneal, ovarian, deep endometriosis, and adenomyosis. This latter classification consists of letter and number coding rather than staging. In 2021, the American Association of Gynecologic Endoscopists introduced another staging classification named AAGL2021.

To investigate the surgery-based performance of Enzian coding versus the AAGL staging classification system, Fadinger et al. from the Department of Gynecology, Obstetrics, and Gynecologic Endoc, Keppler University Hospital, Linz, Austria, used their endometriosis cohort for comparison.

A total of 222 women diagnosed and laparoscopically operated on in their tertiary clinic were included in the study. The extent of endometriosis was intraoperatively classified using rASRM and Enzian classifications until 2021. For patients operated on before November 2021, the AAGL score was assigned retrospectively using the surgical report.

Every patient was evaluated as their demographic features, clinical symptoms, and extension of the endometriosis disease to prepare for statistical analyses. The authors retrospectively applied the translation model for the Enzian classification to a 4-stage classification on those patients. For each compartment, such as ovarian, peritoneal, tubal, rectovaginal, uterosacral, rectal, and so on, the AAGL2021 and Enzian scoring were discussed comparatively. The bowel and the bladder area are the only anatomic areas where AAGL2021 provides more precise size classification. Overall, the comparison of these two classifications resulted in a comparable percentage of patients for each stage. However, the AAGL2021 classification system does not include some deep endometriotic lesions and lesions in the uterosacral compartment. 

The researchers showed that the Enzian system can be translated into a 4-stage format like AAGL2021, but they believe more research is needed. They hope that in the future, new technologies like artificial intelligence could help develop even better ways to classify endometriosis based on how it affects patients.

This important study was recently published in the Journal of Minimally Invasive Gynecology.

Research Source: https://pubmed.ncbi.nlm.nih.gov/39921154/