From the Guidelines
The primary tumor marker for ovarian cancer is CA-125, which is elevated in approximately 80% of women with epithelial ovarian cancer, but its use is most valuable for monitoring treatment response and detecting recurrence rather than initial screening due to limited sensitivity and specificity 1.
Key Points to Consider
- CA-125 levels are not specific to ovarian cancer and can be elevated in non-gynecological malignancies and benign conditions such as endometriosis and ovarian cysts 1.
- Measuring serum carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 levels in addition to CA-125 may help distinguish primary mucinous ovarian tumors 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, with US-based diagnostic models being preferable to CA-125 or the Risk of Ovarian Malignancy Algorithm for distinguishing between benign and malignant ovarian tumors 1.
- A definitive diagnosis of ovarian cancer requires pathological examination by an expert pathologist of tumor samples from either a diagnostic biopsy or, preferably, a surgical specimen 1.
Clinical Application
- CA-125 should be used in conjunction with clinical findings, imaging studies, and tissue diagnosis for the diagnosis and management of ovarian cancer.
- Other tumor markers such as HE4, AFP, hCG, LDH, and inhibin may be relevant for specific ovarian cancer subtypes and should be considered in the context of clinical presentation and histological diagnosis 1.
- The interpretation of tumor marker levels should always consider the potential for false positives and the lack of specificity for ovarian cancer, emphasizing the need for a comprehensive diagnostic approach.
From the Research
Ovarian Cancer Tumor Markers
- CA125 is the most widely used tumor marker for ovarian epithelial cancer 2, 3
- CA125 has been used as the primary ovarian cancer marker for the past four decades, but its use as a diagnostic biomarker has not improved patients' survival 2
- The detection of low volume type II carcinomas in stage IIIa/b is associated with a higher likelihood for optimal cytoreduction, and CA125 may be useful in diagnosing type II ovarian cancer in the early substages of stage III 2
Clinical Use of CA125
- CA125 is of little value in the detection of early ovarian cancer due to lack of sensitivity for stage I disease and lack of specificity 3
- Preoperative levels of CA125 in postmenopausal women may aid the differentiation of benign and malignant pelvic masses 3
- Serial levels of CA125 during chemotherapy for ovarian cancer are useful for assessing response to treatment 3
- CA125 is the ovarian cancer marker against which new markers for this malignancy should be judged 3
Other Tumor Markers
- Other serum tumor markers, including human epididymis protein 4 (HE4), cancer antigen 19-9 (CA 19-9), and carcinoembryonic antigen (CEA), have been used in conjunction with CA125 for diagnosing and monitoring ovarian cancer 4
- HE4 is being increasingly used to identify certain subtypes of epithelial ovarian cancers, particularly serous and endometrioid tumors 4
- CEA is most commonly associated with mucinous ovarian cancers 4
Prognostic Value of CA125
- Preoperative serum CA-125 level can be used as a predictor for the extent of cytoreduction in patients with advanced stage epithelial ovarian cancer 5
- A preoperative CA-125 cut off value of 500 IU/ml may be a promising threshold to predict a successful primary debulking surgery 5
- CA125 is a tumor marker with high sensitivity in ovarian cancer patients, and its determination can be useful in routine follow-up, supplemented with additional imaging procedures 6