Current Endometriosis Scales Fail to Capture Patient-Reported Symptoms

Endometriosis staging is poorly correlated with pain intensity, highlighting limits of current classification systems

Key Points

Highlights: 

• Pain intensity does not seem to be associated with the stage of endometriosis.

Importance:

• Scales offering more accurate anatomical descriptions of endometriosis and more closely aligning with patients’ symptoms are required

What’s done here:

• This is a systematic review and meta-analysis to test whether endometriosis stage reflects pain severity.
• Studies linking rASRM stage with patient-reported pain were identified and pooled.
• Pain outcomes included dysmenorrhea, dyspareunia, and chronic pelvic pain.
• Subgroup analyses examined whether specific pain types correlated with disease stage.

Key results:

• Pain intensity was not associated with endometriosis stage
• Period pain showed the highest mean pain intensity
• Painful urination showed the lowest pain intensity. 
• Chronic pelvic pain was more common among women with advanced endometriosis.

Strengths and Limitations:

• Strengths are: being tbe first meta-analysis to systematically evaluate the relationship between endometriosis stage and pain intensity; inclusion of multiple cohorts and thousands of patients increases generalizability, the use of validated pain scales allows meaningful comparison across studies; and the analysis by pain type provides clinically relevant insight beyond overall pain scores.
• Limitations are: most included studies relied on the rASRM classification, which was not designed to reflect symptom burden; limited data using the ENZIAN system prevented deeper analysis of anatomical pain correlations; high heterogeneity across studies reflects variability in pain reporting and study design; and some pain domains were underrepresented, reducing power for subgroup analyses.

From the Editor-in-Chief – EndoNews

"This meta-analysis addresses a persistent and clinically frustrating paradox in endometriosis care: why the severity of patients’ pain so often fails to match the apparent extent of disease. By systematically showing that pain intensity does not correlate with rASRM stage—with the partial exception of chronic pelvic pain—the study provides strong quantitative evidence that current staging systems were never designed to capture what matters most to patients.

The findings reinforce a growing consensus that endometriosis is not a linear disease, where more lesions automatically mean more pain. Instead, pain emerges from a complex interaction of lesion location, inflammation, neural involvement, central sensitization, and individual pain processing. In this context, the weak association between stage and symptoms is not a failure of patients’ reporting, but a limitation of anatomy-focused classification systems that prioritize surgical description over functional impact.

Importantly, this work does not diminish the value of staging for surgical planning or fertility assessment. Rather, it highlights the danger of using stage as a surrogate for symptom burden, treatment response, or quality of life. When clinicians rely too heavily on staging, they risk underestimating suffering in patients with minimal disease—or overestimating symptom severity in those with extensive but silent lesions.

The study also underscores an urgent need for patient-centered classification frameworks that integrate anatomical mapping with symptom profiles, imaging findings, and possibly biomarkers of inflammation and neural involvement. The ENZIAN system represents progress, but its limited use in the current literature reflects a broader gap between conceptual advances and real-world adoption.

Ultimately, this meta-analysis reframes a familiar clinical observation as robust evidence: in endometriosis, pain is a phenotype of biology, not simply of stage. Future research—and future classification systems—must be built around this principle if we are to align diagnosis, treatment, and outcomes with patients’ lived experience."

Lay Summary

Pain during periods is associated with higher pain intensity in women with endometriosis, according to a new study by Portuguese researchers. On the other hand, painful urination is associated with lower pain intensity. 

Importantly, pain intensity is not associated with endometriosis stage, while chronic pelvic pain seems to be more common among women in the advanced stages of endometriosis.

These findings suggest that scales that offer more accurate anatomical descriptions of endometriosis and are more closely aligned with patients’ symptoms are needed.

“In this context, the ENZIAN classification shows promise, the authors of the study said. “It facilitates a more patient-oriented approach and potentially aligns more closely with patients’ complaints.”

To assess the possible link between endometriosis staging and the type and intensity of pain that patients experience, researchers under the leadership of Dr. Jorge Lima from the Department of Obstetrics and Gynecology at Hospital da Luz Lisboa in Lisboa, Portugal a systematic review of the literature.

The researchers identified 2,527 records that included the terms “endometriosis”, “pain”, “dysmenorrhea”, “dyspareunia”, “pelvic pain”, “dyschezia”, “dysuria”, and “classification”. 

They reviewed a total of 112 studies, of which eight met the inclusion criteria. Seven of these used the revised American Society for Reproductive Medicine (rASRM) classification system, and one used the ENZIAN classification system.

Dysmenorrhea or period pain showed the highest mean intensity, while dysuria or painful urination showed the lowest. 

There was no difference in pain intensity between rASRM stages 1 to 2 and 3 to 4. However, chronic pelvic pain was more common in cases of advanced endometriosis.

The study is published in the Journal of Minimally Invasive Gynecology.

Research Source: https://pubmed.ncbi.nlm.nih.gov/41338448/