CA-125, cancer antigen-125, is a protein that is found at levels in most ovarian cancer cells that are elevated compared to normal cells. CA-125 is produced on the surface of cells and is released in the blood stream.
The CA-125 test assesses the concentration of CA-125 in the blood. The test requires a sample of the patient’s blood to be drawn. The second generation test, compared to the first generation test, is less likely to fluctuate from day to day. The two tests are not interchangeable. The second generation test results are slightly higher than the first generation ones. Both can be used serially as long as the test data in each series is from the same generation test.
Serial CA-125 testing is a series of CA-125 tests repeated over a period of time. Performing several CA-125 test over a period of time allows evaluation of the rate that CA-125 concentration increases. When looking over serial test results check to make sure the test used in each case was the same generation, same manufacturer, and same type of assay.
The rate at which CA-125 levels increase is a more accurate method of detecting the presence of ovarian cancer, than a single CA-125 test. An algorithm by SJ Skates detected 83% of ovarian cancer cases and 99.7% of positive results were truly ovarian cancer. This represents a dramatic improvement on the accuracy of a single CA-125 test.
The CA-125 test only returns a true positive result for about 50% of Stage I ovarian cancer patients. The CA-125 test is not an adequate early detection tool when used alone. The CA-125 test has an 80% chance of returning true positive results from stage II, III, and IV ovarian cancer patients. The other 20% of ovarian cancer patients do not show any increase in CA-125 concentrations.
However several women’s reproductive disorders can cause a false positive result. Endometriosis, benign ovarian cysts, first trimester of pregnancy, and pelvic inflammatory disease all produce higher levels of CA-125. 70% of people with cirrhosis, 60% of people with pancreatic cancer, and 20%-25% of people with other malignancies have elevated levels of CA-125.
A study of about 22,000 post menopausal women 45 years or older screened about 11,000 with the CA-125 test. 468 patients with elevated CA-125 levels were given an ultrasonography test. Of those patients, 29 underwent surgical procedures. 6 had ovarian cancers, 2 had adenocarcinoma of unknown origin, 14 had benign cancers, 4 had fibroids, and 3 had no abnormalities. CA-125 test has a lower specificity in premenopausal women than postmenopausal women.
The CA-125 test is not recommended for use alone as an early detection method. The rate of false positives is very high, and there has been no data concerning change in mortality. The CA-125 test should not be used alone to detect ovarian cancer, but rather with transvaginal sonography and rectovaginal pelvic examination for greater accuracy. Combining detection methods lowers the number of false positive results. The CA-125 test should be done serially for best accuracy.
Test for Ovarian Cancer can help with the following
Key
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Glossary
Cancer
Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.
Protein
Compounds composed of hydrogen, oxygen, and nitrogen present in the body and in foods that form complex combinations of amino acids. Protein is essential for life and is used for growth and repair. Foods that supply the body with protein include animal products, grains, legumes, and vegetables. Proteins from animal sources contain the essential amino acids. Proteins are changed to amino acids in the body.
Intravenous Infusion
(IV): A small needle placed in the vein to assist in fluid replacement or the giving of medication.
Endometriosis
A condition whereby endometrial tissue builds up in parts of the uterus where it does not belong or areas outside of the uterus, forming 'ectopic implants'. Unlike the normal tissue lining the uterus, ectopic tissue has no place to shed in response to a decline in estrogen and progesterone. This results in debris and blood accumulating at the site of the implant leading to inflammation, scarring and adhesions that ultimately cause symptoms and complications. Symptoms typically occur in a cyclic fashion with menstrual periods, the most common being pelvic pain and cramping before and during periods; pain during intercourse; inability to conceive; fatigue; painful urination during periods; gastrointestinal symptoms such as diarrhea, constipation, and nausea.
Benign
Literally: innocent; not malignant. Often used to refer to cells that are not cancerous.
Ovarian Cysts
These occur in two forms, namely "functional" and "organic". may not be present but can include pressure or pain in the abdomen, problems with urine flow or pain during sexual intercourse. Rarely, a very large cyst can become twisted and stop its own blood supply, possibly causing nausea, fever or severe abdominal pain. Functional ovarian cysts form part of the normal functioning of the ovary and are always benign. They may be either "follicular cysts", produced by all menstruating women every month and reaching up to 2-3cm in diameter before they rupture at ovulation, or "corpus luteum cysts", which appear after ovulation and may grow to produce "hemorrhagic cysts" if ovulation does not occur or is delayed. Rupture of such a cyst can sometimes cause painful ovulation or bleeding, which is often moderate and resolves by itself. Organic ovarian cysts may be benign or malignant and are not linked to the functioning of the ovary. They occur as either "dermoid cysts", which are benign tumors that may nevertheless recur on either ovary and contain elements derived from the skin (hairs, sebum, teeth), or other organic cysts.
Pelvic Inflammatory Disease
(PID) A Purulent (pus-like) vaginal discharge with fever and lower abdominal pain.
Cirrhosis
A long-term disease in which the liver becomes covered with fiber-like tissue. This causes the liver tissue to break down and become filled with fat. All functions of the liver then decrease, including the production of glucose, processing drugs and alcohol, and vitamin absorption. Stomach and bowel function, and the making of hormones are also affected.
Menopause
The cessation of menstruation (usually not official until 12 months have passed without periods), occurring at the average age of 52. As commonly used, the word denotes the time of a woman's life, usually between the ages of 45 and 54, when periods cease and any symptoms of low estrogen levels persist, including hot flashes, insomnia, anxiety, mood swings, loss of libido and vaginal dryness. When these early menopausal symptoms subside, a woman becomes postmenopausal.
Premenopause
The period when women of childbearing age experience relatively normal reproductive function (including regular periods).
Postmenopause
The postmenopausal phase of a woman's life begins when 12 full months have passed since the last menstrual period and any menopausal symptoms have become milder and/or less frequent.