Endometriosis Classification, Staging and Reporting Systems: A Review on the Road to a Universally Accepted Endometriosis Classification ^{† ‡} 

Objective: In the field of endometriosis, several classification, staging and reporting systems have been developed. Which endometriosis classification, staging and reporting systems have been published and validated for use in clinical practice? 

Data sources: A systematic PUBMED literature search was performed. Data were extracted and summarized. 

Methods of study selection: na 

Tabulation, integration and results: Twenty-two endometriosis classification, staging and reporting systems have been published between 1973 and 2021, each developed for specific, and different, purposes. There still is no international agreement on how to describe the disease. Studies evaluating the different systems are summarized showing a discrepancy between the intended and the evaluated purpose, and a general lack of validation data confirming a correlation with pain symptoms or quality of life for any of the current systems. A few studies confirm the value of the ENZIAN system for surgical description of deep endometriosis. With regards to infertility, the endometriosis fertility index has been confirmed valid for its intended purpose. 

Conclusion: Of the 22 endometriosis classification, staging and reporting systems identified in this historical overview, only a few have been evaluated for the purpose for which they were developed. The literature search was limited to PUBMED. Unpublished classification, staging or reporting systems, or those published in books were not considered. It can be concluded that there is no international agreement on how to describe endometriosis or how to classify it, and that most classification/staging systems show no or very little correlation with patient outcomes. This overview of existing systems is a first step in working towards a universally accepted endometriosis classification.