From the Guidelines
CA125 testing is generally not recommended for routine cancer screening in the general population. This blood test is primarily used to monitor treatment response in patients already diagnosed with ovarian cancer, rather than as a screening tool. CA125 levels can be elevated in many non-cancerous conditions including endometriosis, fibroids, pelvic inflammatory disease, liver disease, and even during menstruation or pregnancy, leading to false positive results 1. If you're concerned about ovarian cancer risk, especially with a family history or genetic predisposition (such as BRCA1/2 mutations), consult your healthcare provider about appropriate screening strategies. For high-risk individuals, a combination of transvaginal ultrasound and CA125 testing may be considered, but even in these cases, the test has limitations 1. Your doctor can help determine if CA125 testing is appropriate based on your specific symptoms, medical history, and risk factors.
Some key points to consider:
- The specificity of the CA125 test is 98.5% for women over 50, but lower (94.5%) for those under 50 1.
- The use of multimodal screening (serum CA125 measurement and ultrasound imaging) for early detection of ovarian cancer seems to be effective, but is not yet considered the gold standard 1.
- The U.S. Preventive Services Task Force recommends against screening for ovarian cancer in asymptomatic women, as the harms of screening outweigh the benefits 1.
- For women with a family history of ovarian cancer, genetic counseling and consideration of transvaginal ultrasonography and CA125 testing may be appropriate 1.
It's essential to weigh the potential benefits and harms of CA125 testing and discuss your individual risk factors and screening options with your healthcare provider 1.
From the Research
CA125 Testing
- CA125 is a tumor-associated antigen used to monitor ovarian carcinomas, but it has limitations as a screening test due to high frequency of false-positive results associated with benign conditions 2.
- Benign conditions that can increase CA125 levels include menstruation, pregnancy, benign pelvic tumors, pelvic inflammatory diseases, ovarian hyperstimulation syndrome, peritonitis, and diseases leading to pleural effusion or ascites 2.
Reference Levels for CA125
- The generally accepted upper limit of normal for CA125 is 35 U/mL, but this value may vary depending on the menstrual status and menopausal status of the woman 3.
- For normal premenopausal women, the overall upper limit of CA125 should be 50 U/mL, with higher limits during menses (62 U/mL) and lower limits during the luteal phase (32 U/mL) 3.
- For postmenopausal women, the CA125 levels should be no more than 35 U/mL for those with vaginal bleeding and 20 U/mL for those without bleeding 3.
CA125 in Benign Conditions
- Uterine fibroids can increase peripheral CA125 levels, and removal of the uterus or administration of GnRH analogue therapy can decrease these levels 4.
- CA125 levels can be elevated during menstruation, and sampling for CA125 assay should not be done immediately before or during menstruation to avoid false positive results 5.
- CA125 can also be elevated in conditions such as liver cirrhosis, peritoneal infection, abdominal surgery, or cardiac failure, highlighting the need for careful interpretation of results 6.
Interpretation of CA125 Results
- A marked increase in CA125, even up to 5000 units/mL, can be seen in some benign conditions, limiting the value of CA125 as a potential noninvasive procedure to differentiate benign from malignant diseases 2.
- The CA125 assay is not standardized, and different methods can give differing results, emphasizing the need for reference limits appropriate for age and gender 6.