From the Guidelines
Elevated Carbohydrate Antigen 125 (CA 125) levels are primarily associated with ovarian cancer, but can also be seen in other cancers such as pancreatic cancer, as well as in non-cancerous conditions like endometriosis, benign ovarian cysts, pregnancy, and pelvic inflammatory disease. When considering the association of CA 125 with various cancers, it's crucial to understand that while CA 125 is a valuable marker for ovarian cancer, its elevation is not exclusive to this malignancy. According to the study published in the Journal of the American College of Radiology 1, CA 125 levels can be elevated in pancreatic cancer and cirrhosis, highlighting the need for a comprehensive diagnostic approach. Key points to consider include:
- CA 125 serves as a significant tumor marker for ovarian cancer, especially in stages II or greater, where the true-positive rate can be as high as 80% 1.
- The specificity of CA 125 for ovarian cancer can be optimized by considering the CA 125/CEA ratio, which helps differentiate ovarian cancer from gastrointestinal primary neoplasms 1.
- Elevated CA 125 levels are not diagnostic on their own due to potential false positives from non-cancerous conditions, necessitating additional diagnostic procedures for accurate diagnosis.
- The clinical context and correlation with other diagnostic tools are essential for interpreting CA 125 levels, as emphasized by the association of CA 125 levels with the clinical course of patients during chemotherapy and the prediction of tumor recurrence 1.
From the Research
Cancers Associated with Elevated CA 125 Levels
Elevated Carbohydrate Antigen 125 (CA 125) levels are associated with various types of cancers, including:
- Ovarian cancer, particularly epithelial serous cystadenocarcinomas 2, 3, 4, 5, 6
- Breast cancer, especially in cases of malignant tumors 3
- Other gynecological cancers, such as endometrioid and mucinous tumors 3, 4, 6
- Non-gynecological tumors, including teratomas and secondary ovarian malignancies 4
- Clear cell tumors, with an elevated level of CA 19-9 4
- Mucinous ovarian cancers, associated with an elevated level of CEA 4
CA 125 Levels and Cancer Stages
CA 125 levels have been found to correlate with the stage and severity of cancer:
- Higher CA 125 levels are often associated with advanced cancer stages, such as stages III and IV 4, 6
- Undifferentiated carcinomas tend to have higher CA 125 levels compared to low and moderate differentiated grade tumors 6
- Patients with high grade serous carcinoma and elevated CA 125 levels (>500 U/mL) have been found to have improved survival rates 6
Clinical Utility of CA 125
CA 125 has clinical utility in both diagnosis and surveillance of ovarian cancer:
- CA 125 levels can be used to monitor treatment response and detect recurrence 2, 4, 5
- Elevated CA 125 levels can indicate tumor progression or recurrence, even in patients with normal imaging results 5
- CA 125 levels can be used in combination with other tests, such as mesothelin and estradiol, to improve diagnosis and monitoring of ovarian cancer 3, 4