Cervical Cancer and Pap Smears
See also our fact sheet on Vaccines for HPV and Cervical Cancer
If every woman in the world received adequate health care, almost no one would die of cervical cancer. Unless a woman's immune system is compromised, cervical cancer progresses very slowly and can be detected long before it is even potentially life-threatening. Effective treatments exist for pre-cancerous conditions and cervical cancer diagnosed at an early stage. And yet cervical cancer is the leading cause of cancer-related deaths in women in the third world. In the United States 12,900 women are diagnosed with cervical cancer each year and 4,400 women die of it. It is nearly twice as common in African American women as in white women(1).
The cervix opens into the vagina, and this location exposes the cervix to anything that enters the vagina. In the last few years, researchers have gained a better understanding of the connection between human papilloma virus (HPV), a common virus that can be passed from one person to another during sex, and cervical cancer. HPV has been found to be associated with virtually every case of cervical cancer in women who were otherwise healthy. Barrier methods of contraception lower the risk of developing cervical cancer.
However, HPV infection isn't enough to cause cancer on its own and the vast majority of women with HPV never develop cervical cancer. There are many different types of HPV and only a few of them are associated with cervical cancer. Even in those cases where a woman is infected with a type of HPV that can potentially cause cervical cancer, other factors need to be present for HPV to progress to cancer. These co-factors have not been conclusively identified, but studies have found that sex at a young age, smoking cigarettes, using oral contraceptives, and deficiencies of vitamin A and folate (a B vitamin) are all associated with cervical cancer (2).
Screening and early detection
Screening and early detection lower the risk of dying from cervical cancer. We recommend that all women begin regular screening as soon as they are sexually active(3). We interpret "sexually active" to include any kind of uncovered touching by another person of the vulva or vagina. While intercourse is the most common way the HPV virus is transmitted during sex, there is reason to believe that HPV can also be transmitted through genital secretions and oral sex. Women who identify as lesbians should be screened for cervical cancer if they are sexually active. Women should continue getting Pap smears every year until they have had at least three "good" Pap smears in a row and have no other risk factors for cervical cancer. Regular screening at the appropriate interval should continue throughout a woman's life as long as she is sexually active. It may be reasonable to stop screening for cervical cancer if sexual activity ceased many years ago, but cervical cancer develops slowly, so regular screening should continue for at least another ten years. Finally, any woman who has never had a Pap smear should get one, no matter how long it has been since she last had sex.
Improving on the Pap smear?
Pap smears, like many screening tests, also detect conditions which are not cancer, can't turn into cancer and are not dangerous. These conditions are often called atypical squamous cells of undetermined significance (ASCUS). In most cases, these conditions go away on their own. However, too many women are treated unnecessarily after a "bad" Pap. Pap smears also pick up conditions which have the potential to eventually lead to cancer and do need to be treated. Pre-cancerous conditions, such as carcinoma in situ and severe dysplasia, can be treated much less traumatically than cervical cancer which has become invasive. The Network encourages women to inform themselves and be involved in any treatment decisions.
Many companies are trying to develop a better test in hopes of finding the few cancers which are missed by current technology and lab practices. New techniques such as computer-aided review of Pap smears and new ways of preparing smears have been approved by the Food and Drug Administration (FDA). These techniques haven't yet shown that they are any better than standard Pap smears at finding invasive cancer, or serious pre-cancerous conditions, but they identify even more women as having unusual cells (4). HPV tests have recently been recommended as part of routine screening, but they have the same weakness of finding many cases of HPV that will never cause problems(5). These tests are being heavily marketed and companies encourage women to insist on them, but there is not yet data that shows that they will actually improve women's health. (A very low-tech approach that improves detection of cervical cancer will probably never catch on in this country; a large study in Zimbabwe found that wiping the cervix with vinegar and then looking for white areas picked up more cervical cancers than Pap tests (6).) A public health approach emphasizing regular low-tech screening for all would help more women than inventing more expensive, patentable devices and tests.
For More Information/Resources
- The Network has a health information packet on Cervical Cancer/PAP Smears. To order, call the Women's Health Voice at (202) 628-7814 or email firstname.lastname@example.org.
- Our Bodies, Ourselves: A New Edition For A New Era, 2005, Simon & Schuster, New York. This book provides comprehensive descriptions of pap smears and the conditions they test for.
- The federal government sponsors a free cervical cancer screening program for low-income women who cannot qualify for Medicaid.
1. Cancer Facts and Figures - 2001. American Cancer Society. Page 19.
2. A Patient Guide: HPV in Perspective. American Social Health Association, 1995.
3. Guide to Clinical Preventive Services, Second Edition Report of the U.S. Preventive Services Task Force. Pages 105-118 review recommendations for cervical cancer screening. NWHN recommendations are based on this resource, but differ slightly.
4. "New Pap Test Technologies Hit Heavy Seas But Sales Keep Flying" Journal of the National Cancer Institute; September 16, 1998, pages 1327 - 1329.
5. "Current approaches to cervical-cancer screening." New England Journal of Medicine May 24, 2001, pages 1603-1607.
6. "Visual inspection with acetic acid for cervical-cancer screening: test qualities in a primary-care setting." Lancet March 13, 1999, pages 869-873.