A person with ovarian cancer may have high levels of a substance called the CA-125 (cancer or carcinoma antigen-125) in the blood. CA-125 antigen is known by several other names, such as ovarian cancer antigen and CA-125 tumor marker. It is a protein present on the surface of most (but not all) ovarian cells. Thus, significantly high levels of CA-125 may be seen in the blood of ovarian cancer patients. Since all ovarian cancer types do not possess this protein, not all women with ovarian cancer will have high blood levels of CA-125.
CA-125 may be elevated in several noncancerous conditions, such as
- Liver diseases
- Menstrual periods
- Uterine fibroids
- Pelvic inflammatory diseases or PID
Hence, elevated CA-125 levels do not definitely mean that the person has ovarian cancer. The CA-125 blood test is not recommended for screening women with low to moderate ovarian cancer risk. The test, nonetheless, does have several important uses, such as
- Monitoring the response to treatment for ovarian cancer. Declining CA-125 levels generally mean that the tumor is responding to treatment.
- Finding out whether the tumor has returned after successful treatment.
- Screening women with a high risk for ovarian cancer, such as those who have
- Certain abnormal genes: BRCA1 and BRCA2
- The gene associated with Lynch syndrome or Peutz-Jeghers syndrome
- A history of cancer of the breast, colon or uterus
- A family history of ovarian cancer, breast cancer or colorectal cancer (this means any of the first-degree relatives, such as mother, sister, grandmother or daughter have had any of these cancers)
What happens during a CA-125 blood test for ovarian cancer?
The CA-125 blood test is a simple test during which a health care professional collects a blood sample from a vein in the arm by using a small needle. The collection hardly takes five minutes, and no special preparation for the test is needed. There may be slight stinging when the needle goes in and out of the skin. There could also be a little pain or bruising at the needle site, but it goes away on its own without generally causing any significant discomfort. The test results will be assessed by the doctor, who may take a gynecologist’s help if needed.
What are the symptoms of ovarian cancer?
Ovarian cancer may or may not present with any significant symptoms. Ovarian cancer is rarely diagnosed in its early stages due to the lack of any typical signs and symptoms. When present, the symptoms may include
- Abdominal pain or discomfort
- Reduced appetite
- Swollen or distended abdomen
- Heaviness or pain in the pelvic area
- A change in bowel habits, typically constipation
- A frequent urge to urinate
The presence of these symptoms does not necessarily mean ovarian cancer. Nonetheless, consult a doctor at the earliest so that a timely diagnosis may be made.
How do doctors diagnose ovarian cancer?
Doctors may diagnose ovarian cancer by
- Taking detailed medical history, including the symptoms, any underlying health conditions and any significant personal or family history of ovarian, breast or colorectal cancer.
- Performing thorough physical examination particularly pelvic exam to look for a bulky ovary or signs of fluid in the abdomen (called ascites).
- Ordering imaging tests, such as ultrasound, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) scans and barium enema X-ray (to see whether cancer has spread to the large bowel). A chest X-ray may also be done to check whether cancer has spread to the lungs.
- Getting a biopsy done. A small tissue sample from the tumor is collected and examined under a microscope. The biopsy sample may also help in staging and grading cancer and determine the presence of special proteins (such as hormone receptors) that help in planning a proper treatment regimen.
- Performing a laparoscopy to examine the pelvic organs including the ovaries by using a thin, flexible tube with a light source and camera (laparoscope) inserted into the abdomen via a small cut (incision).
- Ordering certain blood tests, such as blood counts, bleeding and clotting time and tests, to check the levels of certain important substances, such as human chorionic gonadotropin (hCG), lactate dehydrogenase (LDH), alpha fetoprotein (AFP) and CA-125, which are linked with ovarian cancer.
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Medline Plus. CA-125 Blood Test (Ovarian Cancer). https://medlineplus.gov/lab-tests/ca-125-blood-test-ovarian-cancer/