From the Guidelines
Elevated CA-125 levels are most strongly associated with ovarian cancer, particularly epithelial ovarian cancer, but can also be found in other types of cancer, including endometrial, fallopian tube, primary peritoneal, pancreatic, breast, lung, colorectal, and lymphoma, as well as in various benign conditions. The use of CA-125 as a diagnostic tool is limited by its lack of specificity, as it can be elevated in conditions such as endometriosis, pelvic inflammatory disease, liver disease, heart failure, and during menstruation or pregnancy 1. When interpreting CA-125 levels, it is essential to consider the clinical context and use the test in conjunction with other diagnostic tools, such as imaging and pathology, to accurately diagnose and monitor cancer patients. Some key points to consider when evaluating CA-125 levels include:
- The normal range for CA-125 is generally considered to be less than 35 U/mL, though values can vary between laboratories 1.
- The trend of CA-125 levels over time is often more informative than any single measurement, particularly when monitoring cancer patients 1.
- Measuring serum carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 levels in addition to CA-125 may help distinguish primary mucinous ovarian tumours from a gastrointestinal metastasis 1.
- Initial imaging should comprise pelvic ultrasound and computed tomography (CT) of the thorax, abdomen, and pelvis to complete clinical staging and aid surgical planning 1. It is crucial to prioritize the most recent and highest quality study, which in this case is the 2023 ESMO clinical practice guideline for diagnosis, treatment, and follow-up of newly diagnosed and relapsed epithelial ovarian cancer 1.
From the Research
Types of Cancers Associated with Elevated CA-125 Levels
- Ovarian cancer: Elevated CA-125 levels were found in patients with ovarian cancer, particularly in serous cystadenocarcinoma 2, 3, 4, 5, 6
- Epithelial ovarian cancer: CA-125 levels were elevated in 96% of patients with epithelial ovarian cancer 3
- Non-ovarian adenocarcinoma: 11/27 patients with non-ovarian adenocarcinoma showed elevated CA-125 levels 6
- Mucinous cystadenocarcinoma: CA-125 levels were markedly low in mucinous cystadenocarcinoma, with a positivity rate of 16% 2
- Endometrioid tumors: CA-125 levels were elevated in endometrioid tumors, but the specificity rate did not change significantly when mucinous types were excluded 5
Other Conditions Associated with Elevated CA-125 Levels
- Early stages of pregnancy: Elevated CA-125 levels were found in the early stages of pregnancy, but not as high as those found in ovarian cancer 2
- Endometriosis: Elevated CA-125 levels were found in endometriosis, but not as high as those found in ovarian cancer 2
- Cervical cancer: CA-125 levels were elevated in cervical cancer, but not as high as those found in ovarian cancer 2