How is ovarian cancer diagnosed?
If a gynecologist has a suspicion that a woman has ovarian cancer, the doctor will order a series of tests. A definitive diagnosis of ovarian cancer usually occurs after surgery. Doctors will perform surgery after they obtain enough evidence from a pelvic exam; radiological tests, such as a transvaginal ultrasound or CT scan; and from blood markers, such as CA-125, an indicator of ovarian cancer. If there is a suspicion from these tests that ovarian cancer might be present, the patient should seek a referral to a gynecologic oncologist before surgery occurs. Research shows that women treated by gynecologic oncologists live longer than those treated by other physicians. The most common preliminary tests are:
• Physical exam: Your doctor assesses your general health. The doctor may press on your abdomen to check for tumors or for abnormal build-up fluid (ascites) in the abdomen due to the cancer. A sample of fluid may be taken with a needle.
• Recto-vaginal pelvic examination (also called a bimanual exam): This exam allows your doctor to examine the ovaries for lumps or changes in shape or size. Every woman should undergo a rectal and vaginal pelvic examination at her annual check-up with her gynecologist. A Pap test is routine in a pelvic exam but it detects cervical cancer, NOT ovarian cancer.
• Transvaginal ultrasound: This test uses sound waves to create a picture of the ovaries, and can often reveal if there are masses or irregularities on the surface of the ovaries and within cysts that form within the ovaries. Fluid-filled cysts are usually not a sign of cancer but cysts that have cells growing in it are. Standards for the interpretation of cysts seen on ultrasound have been developed and radiologists interpret the images to determine the likelihood of cancer and the need for surgery or additional tests.
• Blood tests: Among the blood tests your doctor could order is the CA125 blood test. CA125 is a substance in the blood that may increase when a cancerous tumor is present; this protein is produced by ovarian cancer cells and is elevated in more than 80 percent of women with advanced ovarian cancers and in 50 percent of those with early-stage cancers. Because CA125 misses half of early cancers and can be elevated by benign conditions, the National Cancer Institute does not endorse using it to screen women for ovarian cancer who are at ordinary risk or in the general population. CA125, however, is approved by the Food and Drug Administration to monitor the effectiveness of treatment for ovarian cancer and for detecting disease recurrence after treatment.
• OVA1 test: In September 2009, the Food and Drug Administration approved a test, called OVA1, which can help detect ovarian cancer in women who have a pelvic mass and will require surgery. The test measures the levels of five proteins in blood that change when ovarian cancer is present. OVA1 may be a useful tool in identifying women who should be referred to a gynecologic oncologist for their initial surgery because the women might have ovarian cancer, despite negative results from other clinical and radiological tests. However, this test has not been approved for use as an ovarian cancer screening tool, nor has it been proven to result in early detection or reduce the risk of death from this disease.
• CT scan or computerized tomography: CT scans employ x-rays to take multiple cross-sectional images of the tissues and bones in the body. Doctors can analyze the images individually or use software to make a three-dimensional model of the internal organs. CT scans help define the boundaries of a cancerous tumor and show the extent of tumor spread, helping a doctor determine where to operate. CT scans also are used to monitor disease recurrence. Before undergoing a CT scan, you may receive by mouth or intravenously a contrast material that allows tissues and organs to show up more readily.
• The need for a biopsy: None of the above tests are definitive when used on their own. They are most effective when used in combination with each other. The only way to confirm the presence of ovarian cancer suspected by the tests is through a surgical biopsy of the tumor tissue.
• Surgery: If tests imply a likelihood of ovarian cancer, the doctor will likely perform a laparotomy or laparoscopy depending on what the CT shows. A laparotomy is a surgical procedure involving a long incision in the wall of the abdomen to remove fluid and tissue, such as the ovaries, fallopian tubes, uterus and connecting tissue, depending on how far the cancer has spread. More information about surgery is in the “Treatment” section of the website.
A doctor may also perform laparoscopic surgery to perform the biopsy and remove a small, benign cyst or early ovarian cancer and to determine the extent of spread. A laparoscope is a thin tube with a camera that allows the doctor to see and remove tissue.
If a woman has fluid inside the abdomen, a doctor before surgery may inject a needle through the abdomen wall to collect the fluid for analysis.
By looking at the cells in the tissue and fluid under a microscope, a pathologist describes the cancer as Grade 1, 2, or 3. Grade 1 is most like ovarian tissue while Grade 3 cells are more immature and more likely to metastasize.