Conclusion
The disease entity endometriosis is enigmatic and presents a major
challenge to developers of potential staging systems. This external
validation study demonstrates that the AAGL 2021 endometriosis
classification is not generalisable. One of the key strengths of the
tool is for high stage disease to distinguish a high level of surgical
complexity. While this is of limited utility when endometriosis is
diagnosed intraoperatively, these findings suggest that a corresponding
pre-operative endometriosis staging system might provide the ability to
triage and appropriately plan for the anticipated level of surgical
complexity. This finding is consistent with the performance of existing
ultrasound-based endometriosis staging tools, particularly with higher
stage disease (24). Despite this, survey data suggests that both
patients (25) and gynaecologists (26) have limited awareness of
non-surgical endometriosis diagnosis.
In the ongoing evolution of endometriosis staging and the search for a
universally accepted tool, the AAGL system has some key weaknesses and
important strengths. We support the assertion that the ideal staging
system should incorporate both a pre-operative and intra-operative arm,
predict surgical complexity, correlate well with clinical outcomes
relevant to the patient (27) and demonstrate internal and external
validity. A prospective external validation of the recently published
AAGL system should follow, including a head-to-head comparison with
existing and emerging endometriosis staging systems. Standardized
surgical data collection would be advisable, as per the Consensus on
Recording Deep Endometriosis Surgery statement (28).