CA -125 is a large protein that circulates in the blood stream of women with ovarian cancer. CA-125 can be measured using a simple blood draw and standard laboratory test. For most laboratories, CA-125 levels up to 35 U/ml are normal, but other laboratories use different assays with upper normal limits of 21 U/ml.
CA-125 is found at increased levels in women with ovarian cancer, but is also elevated with benign (non-cancerous) conditions, including endometriosis, pelvic or abdominal infections, liver and heart disease. It is therefore not a cancer-specific marker and the results need to be interpreted by an experienced gynecologic oncologist. The CA-125 tumor marker might be a useful test to perform when the physician has diagnosed a mass on the ovary. If the CA-125 is elevated, strong consideration should be given for referral to expert care.
In patients undergoing treatment for ovarian cancer, the CA-125 tumor marker levels are followed closely to monitor the success of therapy.
Human Epididymis Protein 4 (HE4) is a more recent tumor marker that can be used to follow patients with ovarian cancer in addition to CA-125. It is, however, still unclear whether using HE4 as a tumor marker can improve the prognosis of ovarian cancer patients for example by discovering recurrent cancer earlier than CA-125. HE4 is useful when the physician is uncertain whether a tumor on the ovary diagnosed by ultrasound is benign or cancer. If the tumor is benign, HE4 is almost never elevated.
During a transvaginal ultrasound, a probe is inserted carefully into the vagina to get as close as possible to the ovaries. Ultrasound provides very detailed information about the ovaries, including size, location, cysts or presence of tumors. At the same time, the uterus can be evaluated to assure that the mass does not originate from the ovary.
The pelvic exam includes a speculum exam that allows the inspection of the entire vulva, vagina and cervix. This is particularly important in patients that report bleeding from the vagina. During the bimanual exam, the physician feels the uterus, vagina, ovaries, fallopian tubes, bladder and rectum to check for any unusual changes.
A biopsy is the removal of a small amount of tissue for examination under a microscope. In general, biopsies of the ovaries before surgery are not recommended since this procedure might spread cancer cells outside the ovary. During surgery, suspicious cysts can be removed from the ovaries, or small biopsies might be indicated to make a diagnosis. Biopsies might also be indicated to diagnose recurrent disease. This can then often be done without surgery using a CT or ultrasound guided biopsy.
An x-ray is a picture of the inside of the body. For instance, a chest x-ray can show if the cancer has spread to the lungs. X-rays have largely been replaced by CT scans which are better in detecting cancer and metastasis.
Computed Tomography (CT or CAT) Scan
A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines those images into a detailed, cross-sectional view that shows any abnormalities or tumors.
Magnetic Resonance Imaging (MRI)
An MRI scan uses a magnetic field to obtain a high resolution image of the pelvic and abdominal organs. The contrast obtained between different soft tissues of the body make it useful to better localize areas of cancer.
PET: Positron Emission Tomography (PET)
PET is a nuclear medicine imaging technique that produces a three-dimensional image, and provides information about metabolic activity. The patient receives an injection of radioactive sugar (glucose). Since cancer cells need high levels of energy to grow, they take up glucose at a higher rate than normal tissue. The more metabolically active the cancer cells, the greater the uptake will be and the greater the intensity of the signal. PET scanning is widely used in ovarian cancer nowadays.