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

OBJECTIVE: To study the relationship between age and the phenotypic expression and surgical complexity of endometriosis using the American Association of Gynecologic Laparoscopists (AAGL) classification. DESIGN: Retrospective cohort study. SUBJECTS: Patients aged 18-51 years with pathology-confirmed stage III-IV endometriosis. EXPOSURE: 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). MAIN OUTCOME MEASURES: 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. RESULTS: 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 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 45 years). No significant association between age and bowel endometriosis was found. CONCLUSION: 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.