Is endometriosis a progressive disease? Examining age-related trends in disease severity and surgical complexity

To study the relationship between age and the phenotypic expression and surgical complexity of endometriosis using the American Association of Gynecologic Laparoscopists (AAGL) classification.

Retrospective cohort study.

Patients aged 18-51 years with pathology-confirmed stage III-IV endometriosis.

We analyzed patients who underwent laparoscopic or robot-assisted endometriosis surgery between 2013 and 2023 at a quaternary care institution in the United States. Patients were stratified into 4 age groups (≤25, 25-35, 35-45, and >45 years).

The primary outcome was age-related differences in disease severity (AAGL classification), surgical complexity (AAGL levels A-D), the presence of endometrioma, and bowel endometriosis. Secondary outcomes included association with clinical presentation, imaging findings, and surgical complications.

A total of 1,293 patients met inclusion criteria. The AAGL stage III-IV prevalence increased with age, peaking at 50.5% in the 35-45-year age group and then stabilizing at 47.0% in the >45-year age group. American Association of Gynecologic Laparoscopists surgical complexity continued to increase steadily with level C increasing from 21.1% (≤25 years) to 58.3% (>45 years). In multivariable regression, compared with patients aged <25 years, those aged 25-35, 35-45, and >45 years had significantly higher odds of AAGL stage III-IV disease (adjusted odds ratios [aORs], 2.47 [95% confidence interval {CI}, 1.35-4.49], 2.54 [95% CI, 1.40-4.61], and 2.84 [95% CI, 1.42-5.66], respectively). Surgical complexity (AAGL levels C-D) significantly increased beyond the age of 35 years, with aORs of 2.13 (95% CI, 1.22-3.72) for patients aged 35-45 years and 4.46 (95% CI, 2.32-8.59) for patients aged >45 years. The odds of having endometriomas was higher for all age groups than for the age of <25 years (aOR, 3.05 [95% CI, 1.73-5.39] for the ages of 25-35 years; aOR, 3.24 [95% CI, 1.84-5.70] for the ages of 35-45 years; and aOR, 2.58 [95% CI, 1.34-4.96] for the ages of >45 years). No significant association between age and bowel endometriosis was found.

Association of Gynecologic Laparoscopists disease stage peaks around the ages of 25-35 years and subsequently plateaus, whereas surgical complexity continues to increase beyond this age, reaching the highest odds in patients aged >45 years, likely reflecting cumulative fibrosis, adhesions, and anatomical remodeling. These findings highlight the importance of individualized, age-specific treatment approaches to reduce surgical complexity later in life. Future research should further refine these age-based management strategies.