Tumor antigen CA-125 is a glycoprotein biomarker found in various organs such as the bronchi, pancreas, stomach, kidneys, colon, and ovaries, as well as in amniotic fluid, breast milk, or serum of pregnant women. While CA-125 is commonly used to diagnose ovarian cancer, it can also serve as a secondary marker in other diagnostic scenarios, such as pancreatic cancer. However, its efficacy may be limited in certain conditions due to its low sensitivity and clinical specificity.
When is CA-125 recommended?
- Establishing a malignant diagnosis for organs like the ovaries, uterus, pancreas, stomach, colon, and rectum.
- Establishing a benign diagnosis for conditions such as ovarian neoplasms, pregnancy, salpingitis, cirrhosis, pancreatitis, and renal failure.
CA-125 and Endometriosis
A study conducted in 1998 on 2131 patients indicated a low diagnostic rate of CA-125 for grade I / IV endometriosis, with more satisfactory results observed in the diagnosis of grade III/IV endometriosis. Despite these findings, routine CA-125 analysis in infertility patients is preferred to identify subgroups that may benefit from earlier laparoscopic evaluation for endometriosis. Future studies on the interdependence between biomarkers, patient history data, and physical examination are recommended.
Another analysis of 182 studies published in the last 25 years aimed to evaluate proposed immunological markers for endometriosis in serum, plasma, and urine. While over 200 potential endometrial tissue biomarkers were identified, their sensitivity and specificity were not elucidated. However, 32 studies identified six biomarkers potentially related to fibrous fiber growth or cell cycle control, warranting further investigation.
Recommendations of international forums The European Society for Assisted Human Reproduction and Embryology does not recommend CA-125 as a diagnostic method for endometriosis due to its low clinical specificity. CA-125 lacks primary specificity for endometriosis and does not correlate with the disease stage. Currently, no immunological biomarker can non-invasively diagnose endometriosis.
Anamnesis, transvaginal ultrasound, MRI imaging with an endometriosis protocol, and Hydro Colo CT remain accepted diagnostic methods for endometriosis in Europe. Further studies are needed for identified markers to potentially serve as diagnostic tools and predict patient response to treatment. Improved therapeutic interventions may result from clinical markers accurately predicting the presence or absence of the disease without surgical diagnosis.