Cervical Cancer Screening

By Linda Bren

A Pap smear has long been a part of a woman's routine health care. The Pap can detect cell changes that may lead to cancer of the cervix, the lower part of the uterus, or womb. Women age 30 and older can now opt to get an additional test along with their Pap smear to increase the odds of detecting abnormal, or precancerous, cells before they turn into cervical cancer. This test checks a sample of cervical cells for the presence of the genetic material (DNA) of human papillomaviruses (HPVs).

"One of the high risk factors for having cervical cancer is a persistent HPV infection," says Thomas Simms, a Food and Drug Administration biologist who evaluated the HPV DNA test. "Greater than 95 percent of cervical cancers have detectable HPV DNA in them."

In March 2003, the FDA approved the HPV DNA test to be used simultaneously with the Pap test to screen for cervical cancer in women age 30 and older. The Hybrid Capture 2 High-Risk HPV DNA, made by Digene Corp. of Gaithersburg, Md., was initially approved in 2000, but only as a follow-up test for women who had abnormal or inconclusive Pap tests.

The Tests and What They Mean

A woman who visits her doctor to have a Pap test may be offered the HPV DNA test as well. "A woman 30 years and older has an option to choose to have the HPV testing," says Noel Del Mundo, M.D., an FDA gynecologist. Women who have both the Pap and the HPV DNA tests performed will not notice any difference in the procedure. The doctor will collect cervical cells for both tests at the same time by gently rubbing the surface of the cervix with a special collection device. The cells will then be sent to a laboratory for analysis.

If both the Pap and the HPV DNA test results are negative, a woman's doctor may advise her to wait for three years before being retested, according to guidelines from the American College of Obstetricians and Gynecologists (ACOG). But more frequent testing is recommended if other high risk factors are present, such as a weakened immune system or a history of cervical cancer.

If only one of the tests is negative, the doctor may advise the woman to return for retesting in six to 12 months. But if the Pap smear shows a mild cellular abnormality (called atypical squamous cells of undetermined significance, or ASC-US), and the HPV DNA test is positive, the doctor may recommend further tests. "HPV DNA testing for women with mild cellular abnormality will help the physician determine whether the patient should have a colposcopy and biopsy," says Del Mundo.

In a colposcopy, the doctor looks for a lesion on the cervix with a special magnifying instrument called a colposcope. If a lesion is found, the doctor will take a biopsy, in which a sample of the lesion is removed to check it for precancerous cells.

The FDA cautions that, while a positive HPV test can provide useful information for a woman and her doctor, it does not necessarily mean that she will develop cervical cancer. And although negative Pap and HPV test results indicate a very low risk (0.2 percent) for developing cervical cancer, that doesn't mean that changes won't occur. Infections or changes in cells may arise in the future, so continued screening is important.

Although the HPV DNA test in conjunction with the Pap test is not advised for women under age 30, these women should still get annual Pap tests, according to ACOG guidelines. The first screening for cervical cancer should occur about three years after a woman has her first sexual intercourse, but no later than age 21.

All women, regardless of negative test results, should still visit their doctors yearly for a pelvic examination, which includes checking the reproductive and other organs for abnormality in shape or size.

HPVs are Common

There are more than 100 types of HPV, according to the American Cancer Society (ACS). Some of them cause the noncancerous warts that typically grow on the hands or the bottom of the feet.

Other types of HPVs are sexually transmitted. Some cause wart-like growths on or around the genitals and anus of both men and women, but these visible external warts have not been linked with cancer. Other HPVs cause visible warts in the cervix, but because they rarely develop into cancer, they are often referred to as "low-risk" HPVs. But still other types of HPVs have been linked with cancer. These "high-risk" HPVs aren't usually found as visible warts. Both high-risk and low-risk types can cause the growth of abnormal cells in the cervix. The HPV DNA test can detect the presence of 13 HPVs that are associated with a high risk of cervical cancer.

Sexually transmitted HPV infections are very common. Fortunately, it is very rare for an HPV infection to lead to cervical cancer. This is especially true for women under 30, who have a relatively high rate of HPV infection but rarely develop cervical cancer, says Simms. The HPV DNA test was approved for women age 30 and older because of the higher risk of cervical cancer in this age group. "Women over 30 have fewer HPV infections, but if they develop a persistent HPV infection, it can eventually lead to precancerous changes in the cervix," says Simms.

According to the ACS, most people will not know that they have HPV because it usually goes away on its own.

"Most HPV infections are detected only transiently--the body's immune system clears signs of the infection," says Laura Koutsky, Ph.D., professor of epidemiology at the University of Washington in Seattle. "Currently, it is not known if the virus clears in most women or only a few women," she says. "Regardless, if the virus is no longer detectable, a woman's risk for cancer appears to be very low."

Because HPVs can be sexually transmitted, a positive HPV DNA test result may be troubling to women and their partners. But testing positive for HPV does not necessarily mean that the virus was contracted recently, says Koutsky. "You or your husband or partner may have contracted the virus many, many years ago," she says. "Keep in mind that current estimates indicate that more than 50 percent of sexually active adults have been infected with HPV."

Regular Screening Is Important

The ACS estimates that in 2003, more than 13,000 new cases of invasive cervical cancer will have occurred in the United States, resulting in 4,100 deaths from the disease. The rates of death from cervical cancer for several racial and ethnic groups, such as Hispanics and American Indians, are higher than the national average. And for blacks, the death rate is more than twice the national average.

The National Cancer Institute reports that regular Pap screening does reduce deaths from cervical cancer. Women who have not been screened face a significantly greater risk of developing the disease. With regular screening and follow-up care, cervical cancer is avoidable, and, if caught early, curable.

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For More Information

National Cancer Institute
Cervical Cancer Home Page
www.cancer.gov/cancerinfo/types/cervical
(800) 4-CANCER (800-422-6237)
TTY: (800) 332-8615

American Cancer Society
Cervical cancer page
www.cancer.org (click on "choose a cancer topic," then "cervical cancer")
(800) ACS-2345 (800-227-2345)

American Social Health Association
National HPV and Cervical Cancer Resource Center
www.ashastd.org/hpvccrc
(877) HPV-5868 (877-478-5868)

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Preparing for a Pap Test

The American Cancer Society recommends the following to women to ensure that their cervical cancer screening tests are as accurate as possible:

Try not to schedule an appointment for a time during your menstrual period.
Do not douche for 48 hours before the test.
Do not have sexual intercourse for 48 hours before the test.
Do not use tampons, birth control foams, jellies, or other vaginal creams or vaginal medications for 48 hours before the test.

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