Correlation of Serum CA-125 and CA-19-9 Levels with the Severity of Endometriosis: A Cross-Sectional Study

Background: Endometriosis is a chronic, estrogen-dependent gynecological disorder characterized by the presence of endometrial-like tissue outside the uterine cavity. Diagnosis relies on invasive laparoscopy, and noninvasive biomarkers such as CA-125 and CA-19-9 have been investigated to reflect disease severity. Objective: To evaluate the relationship between serum CA-125 and CA-19-9 levels and the severity of endometriosis, assessing their potential role as noninvasive biomarkers. Materials and Methods: This cross-sectional comparative study was conducted at the Department of Obstetrics and Gynaecology, Bangladesh Medical University, Dhaka, from January 2013 to August 2014. Seventy women undergoing laparoscopy or laparotomy for suspected pelvic or ovarian endometriosis were included. Serum CA-125 and CA-19-9 were measured preoperatively using the IMMULITE 2000 immunoassay. Endometriosis was staged intraoperatively according to the Revised American Fertility Society (R-AFS) classification. Statistical analysis included mean ± SD calculation, one-way ANOVA, and Spearman’s rank correlation. Results: Among 70 patients, Stage I, II, III, and IV endometriosis were observed in 10%, 20%, 24.3%, and 45.7%, respectively. Mean CA-125 levels increased significantly with disease severity (Stage I: 21.8 ± 15.1 U/mL; Stage IV: 117.0 ± 41.6 U/mL; p = 0.001). Similarly, mean CA-19-9 levels rose progressively (Stage I: 8.4 ± 5.2 U/mL; Stage IV: 38.8 ± 29.6 U/mL; p = 0.001). Spearman’s correlation showed a strong positive association between CA-19-9 and disease stage (ρ = 0.674, p < 0.001) and a moderate correlation for CA-125 (ρ = 0.547, p < 0.001). Conclusion: Serum CA-125 and CA-19-9 levels correlate positively with endometriosis severity. Although neither marker is specific enough for standalone diagnosis, their combined measurement may assist in reflecting disease burden and guiding clinical assessment alongside laparoscopic evaluation.