Ovarian Cancer

Description

Diagnosis

Up to 95% of women diagnosed with ovarian cancer will survive longer than 5 years if their cancers are treated before they have spread beyond the ovaries. Unfortunately, there are no screening tests for ovarian cancer that are the equivalent to mammography for early detection of breast cancer. Therefore, only about 25% of ovarian cancer cases are diagnosed at such early stages. It is possible to perform genetic screening in high-risk women, but this raises some complex issues.

Mammography is a low-powered x-ray technique that gives a picture of the internal structure of the breast. A mammogram may help in the diagnosis of breast problems including cancer. It is recommended a woman have a baseline mammogram at age 40 followed by a mammogram every couple of years until age 50. After 50, a woman should have a mammogram every year.

Annual Gynecologic Checkup

Every woman should have a regular annual examination with her physician that includes the following.

Pelvic examination. Routine exams called bimanual pelvic examinations are a reasonable precaution, although they are not perfect screening methods due to their low sensitivity. This exam can be performed two ways. In the more common method, the physician inserts two fingers into the vagina while palpating the abdomen with the other hand. The other method, called a bimanual rectovaginal exam, involves the insertion of one finger into the vagina and another into the rectum.

Either exam enables the physician to assess the size of the ovaries as well as the contour and mobility of the uterus and to feel for masses and growths. The rectovaginal exam may reveal rectal lesions that may otherwise go unnoticed and is particularly important for women over 50. A mass felt on pelvic exam often requires further evaluation by ultrasound and sometimes requires surgery to make a definitive diagnosis.

Pap smear. This test is specifically designed to detect cervical cancer. In very rare instances, however, it may reveal abnormal ovarian cells, which might indicate the presence of an ovarian cancer.

Click the icon to see an image of a pap smear.

Unfortunately, ovarian cancer rarely produces changes that are detectable during a regular checkup.

Ruling Out Benign Conditions

An estimated 290,000 women are hospitalized each year in the United States because of ovarian growths or lesions; many more women are informed of some ovarian abnormality during their annual ob/gyn check up. The vast majority of conditions are noncancerous. They include the following:

• Benign functional ovarian cysts.
• Abscesses and infection.
• Fibroids.

Click the icon to see an image of a fibroid tumor.

• Endometriosis.
• Polycystic ovaries.

Click the icon to see an image of a polycystic ovary.

• Ectopic pregnancies.

Click the icon to see an image of an ectopic pregnancy.

• Meig's syndrome (which involves a benign ovarian growth associated with fluid buildup in the abdomen and around the lungs).
• Ovarian hyperstimulation syndrome following fertility treatments.

Once a growth is detected, additional tests as outlined below may help the physician gauge the risk for it being cancerous.

Transvaginal Ultrasound and Other Imaging Tests

Ultrasound. Ultrasound is a noninvasive diagnostic tool that is used to evaluate tumors and masses discovered during the rectovaginal exam:

• Typically, a probe is placed in the vagina that emits sound waves (ultrasound), which bounce off tissues, organs, and masses in the pelvic cavity. These echoes are collected and converted into a picture of the area called a sonogram.

Click the icon to see an image of transvaginal ultrasound.

• The ultrasound probe may also be placed on abdominal walls above the ovaries (transabdominal ultrasound), but it does not provide as clear a picture of the ovaries. Healthy tissue, fluid-filled cysts, and solid tumors produce different sound waves.

Unfortunately, ultrasound does not provide enough specific information to reliably determine which abnormal masses are malignant and which are benign.

• Studies suggest that small so-called simple cysts (i.e., fluid-filled without an associated mass) are usually noncancerous, particularly when they appear in premenopausal women whose blood tests for the protein CA-125 are normal. Such women are sometimes given oral contraceptives and observed for a few months to see if the cyst goes away.
• Postmenopausal women with small simple cysts and normal CA-125 levels may sometimes be observed for a time if they have no other risk factors or symptoms of ovarian cancer.
• In contrast, a "complex" cyst (one that shows a mass or other abnormalities) is often surgically removed, since it has a higher chance of being malignant. It should be noted, however, that even among these cysts only about a small percentage turn out to be malignant. (In one study 6% of complex cysts were actually cancerous.)

Click the icon to see an image of an ovarian cyst.

Other Imaging Techniques. Other imaging techniques used less commonly in the diagnosis or evaluation of suspected ovarian cancer include the following:

• Computed tomography (CT). Computed tomography records X-ray absorption rates of tissue and bone. This data is converted into clear images on a screen. CT scans are useful to determine if cancer has spread to the lymph nodes, abdominal organs, abdominal fluid, and the liver.

Click the icon to see an image of a CT scan.

• Magnetic resonance imaging (MRI). MRI creates multiple cross-sectional images of the pelvis and abdominal organs, which are assembled into three-dimensional images. They are being investigated for preoperative assessment of patients with possible ovarian cancer. Their value is undefined, however, and most patients do not require them prior to undergoing a definitive surgical procedure.

Click the icon to see an image of a MRI scan.

• Abdominal X-rays.

Click the icon to see an image of an x-ray machine.

CA-125 Blood Test

CA-125 is a protein that is secreted by ovarian cancer cells and is elevated in over 80% of patients with ovarian cancer. The CA-125 blood test is not approved for screening in the general population. Oncologists will usually only obtain a blood test for this protein if ovarian cancer is strongly suspected or has been diagnosed. In general, a CA-125 level is considered to be normal if it is less than 35 U/mL (microns per milliliter).

The test is not useful for diagnosis or early screening, however. In approximately half of women with very early ovarian cancer, CA-125 levels are not elevated above the normal standard at all. Furthermore, an elevated level can be caused by a number of other conditions including the following:

• Endometriosis (which may be a risk factor for ovarian cancer).
• Fibroids.
• Noncancerous ovarian cysts.
• Pregnancy.
• Pelvic inflammatory disease.
• Liver diseases.
• Other tumors, such as breast, colon, lung, and pancreatic cancers.
• Age and menstrual status can also affect the levels of CA-125.

Investigative Tests

Ongoing research is underway to find better tests that will detect this cancer in early stages. A promising new approach relies on a technique called proteomics. Proteomics is the analysis of certain proteins. In this case, researchers are looking at a unique pattern of proteins produced by ovarian cancer cells. Studies suggest this set of proteins serves as an early biomarker for detecting ovarian cancer. Scientists at the NCI and FDA have developed a blood test to check for the presence of these abnormal proteins. In one study, the proteomics tool identified 100% of patients with ovarian cancer and incorrectly diagnosed cancer in only 3 out of 66 of women who were actually cancer-free. A clinical trial is now underway comparing the proteomics test to the CA-125 test. OvaCheck, another investigational ovarian cancer blood test, is based on principles similar to the NCI/FDA platform, but is being developed independently by a private corporation. Scientists are also looking into the possibility that the protein osteopontin may be a biomarker for ovarian cancer. Studies have shown that osteopontin is overexpressed in tumors and serum of women with ovarian cancer.

Exploratory Surgery

An exploratory surgical procedure called laparotomy generally is required for the definitive diagnosis of ovarian cancer. Laparotomy involves the following steps:

• It requires general anesthesia and employs standard surgical techniques to make a vertical, midline incision from the pubic bone to the navel.
• Such an incision ensures careful evaluation of the entire abdominal area. After the incision is made, the surgeon assesses the fluid and cells in the abdominal cavity.
• During this procedure, cysts or other suspicious areas will be removed and biopsied (tested for cancer).
• If the lesion is cancerous, the surgeon continues with a process called surgical staging to ascertain how far the malignant tumor has spread and to remove the ovaries and any cancerous tissue.

Investigators are also studying laparoscopy instead of more invasive surgery - for initial surgical evaluation (staging).

Click the icon to see an image of pelvic laparoscopy.