Screening and Prevention

Screening

Screening tests are used to identify cancers very early, when the possibility of successful treatment is highest. Finding cancer early improves your chances that it can be treated successfully. 

Cervical cancer can usually be found early by having regular Pap tests. Now that more women are having Pap tests, preinvasive lesions (precancers) of the cervix are found much more often than invasive cancer. Early detection prevents early cervical cell changes from becoming cancerous and greatly improves the chances of successful treatment.

• Pap test (sometimes called Pap smear or cervical smear) - This simple test is used to look at cervical cells. The Pap test is done in a doctor's office or clinic during a pelvic exam. The doctor or nurse scrapes some cells from the cervix and smears the cells on a glass slide. In a new type of Pap test, known as the liquid-based Pap test, the cells are rinsed into a small container of liquid and a special machine puts the cells onto slides. For both types of Pap test, a lab checks the cells on the slides under a microscope to see if the sample has cervical cancer cells or abnormal cells that could become cervical cancer.

The American Cancer Society, American College of Obstetricians and Gynecologists, Association of Reproductive Health Professionals, Society of Gynecologic Oncologists, and U.S. Preventive Services Task Force jointly recommend that women begin having Pap tests 3 years after they first have sexual intercourse or when they reach age 21, whichever comes first. Women should be screened every year with a conventional Pap test or every 2 years with a liquid-based test. Women with three normal test results in a row can be screened every 2 to 3 years. Women with HIV infections (the virus that causes AIDS) should be screened more often.

Women aged 65 to 70 who have had at least three normal Pap tests and no abnormal Pap tests in the past 10 years should talk to their doctor about whether they should still be screened for cervical cancer. Women who have had a hysterectomy (surgery to remove the uterus and cervix) do not need to be screened for cervical cancer, unless they had the surgery to treat precancerous cells or cancer.

In most cases, any abnormal cells found by a Pap test are not cancerous. However, some abnormal conditions can become cancer over time:

• Low-grade squamous intraepithelial lesions (LSILs) - These mild cell changes on the surface of the cervix are often caused by HPV infections. LSILs are common, especially in young women, and they are not cancer. Even without treatment, most LSILs do not change or go away. However, some turn into high-grade lesions, which may lead to cancer.

• High-grade squamous intraepithelial lesions (HSILs) - These precancerous cells are found only on the surface of the cervix and they look very different from normal cells. HSILs are not cancer, but they may lead to cancer if they are not treated.

Doctors can now test for the types of human papillomavirus (HPV) that are most likely to cause cervical cancer by looking for pieces of the DNA (a chemical that carries the instructions for nearly everything our cells do) of these viruses in cervical cells.

• HPV DNA test - The sample is collected in the same way as for a Pap test and in some cases the DNA HPV test can even be done on the same sample as the Pap test. At least 30 different types of HPV strains target the genital area and are transmitted through sexual, skin-to-skin contact. The HPV DNA test can detect the 13 types of HPV that are related to cervical cancer. The results of this test can be used to figure out whether you need Pap tests every year or whether it’s safe for you to have a Pap test every 3 years.

The U.S. Food and Drug Administration has approved the HPV DNA test in combination with the Pap test to screen women over 30 years old. The HPV DNA test can also be used in women with slightly abnormal Pap test results to find out if they need more testing or treatment.

• If the results of both the Pap and HPV DNA tests are negative (normal), you won’t need to be tested again for 3 years.
• If the Pap test is negative (normal) and the HPV DNA test is positive, you should have the Pap and HPV DNA tests again in 6 to 12 months.
• If both tests are positive, you should talk to your doctor about what to do next.

Prevention

Many cases of cervical cancer can be avoided by preventing precancerous changes by reducing your risk of getting HPV and by finding and treating precancers before they become cancerous.

• Avoiding risk factors - You can lower your chances of getting precancers of the cervix by reducing your exposure to HPV. HPV does not always cause warts or other symptoms, so a person may have the virus and pass it on without knowing it. You can reduce your exposure to HPV by:
  • Delaying having sexual intercourse if you are young.
  • Limiting your number of sexual partners.
  • Avoiding sex with people who have had many other sexual partners.
  • Using condoms during sex. Condoms cannot protect you completely from HPV, but they can make you less likely to be infected with the virus.

Not smoking is another important way to reduce the risk of cervical cancer and precancer.

• HPV vaccine - A new vaccine, Gardasil^®, can protect women from HPV infections. Research studies show that the vaccine is effective in reducing the incidence of adenocarcinoma in situ and cervical intraepithelial neoplasia in women with no evidence of contact with HPV. This vaccine should be used to prevent HPV infection before an abnormal Pap test develops; it cannot be used to treat an existing infection. The HPV vaccine requires a series of three injections over a 6-month period. The second injection is given 2 months after the first one, and the third is given 4 months after the second.

To be most effective, the vaccine should be given before a person becomes sexually active. The Federal Advisory Committee on Immunization Practices (ACIP) and the American Cancer Society recommend that the vaccine be routinely given to girls aged 11 to 12 and as early as age 9 years depending on their doctor’s advice. Some experts also recommend that women ages 13 to 26 who have not yet been vaccinated receive "catch-up" vaccinations. However, the vaccine is less effective for women who already have HPV.

This content has been reviewed and approved by Myo Thant, MD.