From the Guidelines
Elevated Cancer Antigen 125 (CA 125) levels combined with the presence of ascites strongly suggests ovarian cancer, particularly epithelial ovarian carcinoma. CA 125 is a tumor marker that typically rises above the normal threshold of 35 U/mL in ovarian malignancies, while ascites (abnormal fluid accumulation in the peritoneal cavity) often develops as cancer cells spread within the abdomen. However, this combination is not definitively diagnostic of cancer, as elevated CA 125 can occur in other conditions including endometriosis, pelvic inflammatory disease, liver cirrhosis, and heart failure 1. Similarly, ascites can result from non-malignant causes such as liver disease or heart failure.
When these findings are present, a comprehensive evaluation is necessary, including:
- Transvaginal ultrasound
- CT or MRI imaging
- Often surgical assessment with tissue biopsy for definitive diagnosis The combination of elevated CA 125 and ascites warrants urgent gynecologic oncology consultation, as early diagnosis significantly improves outcomes in ovarian cancer 1. The degree of CA 125 elevation (with levels sometimes reaching thousands of U/mL in advanced ovarian cancer) and the characteristics of the ascitic fluid can provide additional diagnostic information.
It's also important to note that CA 125 levels can be used to predict tumor recurrence in patients who are clinically tumor free, and a high CA-125/CEA ratio has been shown to optimize specificity for ovarian versus gastrointestinal primary neoplasms 1. A definitive diagnosis of ovarian cancer requires pathological examination by an expert pathologist of tumour samples from either a diagnostic biopsy or, preferably, a surgical specimen 1.
From the Research
Elevated CA 125 and Ascites
- An elevated Cancer Antigen 125 (CA 125) level and the presence of ascites can indicate various conditions, including ovarian carcinoma and liver disease 2, 3.
- CA 125 is a nonspecific marker of ascites, and its elevation can be seen in both benign and malignant conditions, such as liver cirrhosis, hepatocellular carcinoma, and ovarian cancer 3.
- The presence of ascites and an elevated CA 125 level requires a thorough evaluation for liver disease, as well as the possibility of ovarian carcinoma 2.
Differential Diagnosis
- A high CA 125 level can be associated with non-gynecological tumors, such as non-Hodgkin's lymphoma, and non-malignant diseases involving the peritoneum 4.
- Ovarian thecomas, a type of benign ovarian tumor, can also present with elevated CA 125 levels and ascites 5, 6.
- Meigs' or atypical Meigs' syndrome, a rare condition characterized by a benign ovarian tumor, ascites, and elevated CA 125, should be considered in the differential diagnosis 5.
Diagnostic Approach
- A thorough diagnostic workup, including imaging studies and serum tumor markers, is essential to differentiate between benign and malignant conditions 6.
- Cytology and biopsy of the retroperitoneal mass or ascites can help establish a definitive diagnosis 4.
- It is crucial to consider a broad differential diagnosis in patients with ascites and elevated CA 125 levels, rather than relying solely on tumor markers to differentiate between benign and malignant masses 5, 4.