The Basics of Cervical Cancer

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Cancer of the cervix is the second most common type of cancer found in women after breast cancer in the world. In the United States, cervical cancer is the twelfth most common cancer in women, affecting an estimated 500,000 women worldwide each year. The American Cancer Society estimates that about 9,710 cases of invasive cervical cancer will be diagnosed in the United States in 2006, and about 3,700 women will die from the disease.

Cervical cancer is a disease in which cancer cells are found in the tissues of the cervix. The cervix, the lower part of the uterus, connects the body of the uterus to the vagina. Nearly all cases of cervical cancer can be linked to the human papillomavirus, or HPV, a sexually transmitted virus.

The normal cervix is a healthy pink color and is covered with scale-like cells called squamous cells. The cervical canal is lined with another kind of cell called columnar cells. But the area where the two cells meet — called the squamocolumnar junction and transformation zone (T-zone) — is the most likely area for abnormal cells to develop. The T-zone is more exposed on the cervix of young women (teens through 20s), making them more susceptible to cervical infections.

Health care professionals use the Pap test to find cellular abnormalities in cervical tissue that has already or may become cancerous. The earlier cervical cancer is diagnosed, the better the chance for a cure. The American Cancer Society reports that both incidence and deaths from cervical cancer have declined markedly over the last several decades, due to more frequent detection of preinvasive and cancerous lesions of the cervix from increased Pap screening. There is a direct relationship between the use of the Pap smear as a screening tool for cervical cancer and the reduction of the incidence of cervical cancer, according to the American Society for Clinical Pathologists.

In its earliest stages, cervical cancer usually causes no symptoms. Irregular bleeding, bleeding or pain during sex, or vaginal discharge may be symptoms of more advanced disease. These symptoms should always be discussed with a health care professional.

All women are at risk for developing the disease, but several factors can increase a woman's risk of developing cervical cancer, according to the American Cancer Society:

• Infection with human papillomavirus (HPV), a common sexually transmitted disease in the U.S. (Most women and men who have been sexually active have been exposed to the HPV virus, which is spread through skin-to-skin contact with an HPV-infected area. However, certain types of sexual behavior increase a woman's risk of getting an HPV infection, such as having sex at an early age, having many sexual partners and having unprotected sex at any age.)
  
  Recent studies find that using condoms cannot completely protect against HPV because the virus is passed by way of skin-to-skin contact, including the skin in the genital area that may not be covered by a condom. Correct and consistent condom use is still important, however, to protect against AIDS and other sexually transmitted diseases.
  
  

• Smoking cigarettes, which exposes the body to cancer-causing chemicals absorbed initially by the lungs but then carried in the bloodstream throughout the body. The chemicals produced by tobacco smoke may damage the DNA in cells of the cervix and make cancer more likely to occur there.
  
  
• Infection with chlamydia bacteria, which is spread by sexual contact and may or may not cause symptoms. Researchers don't know exactly why chlamydia infection increases cervical cancer risk, but they think it might be because active immune system cells at the site of a chlamydia infection might damage normal cells and cause them to turn cancerous.
  
  
• A diet low in fruits and vegetables. Women who don't eat many fruits and vegetables miss out on the protective antioxidants and phytochemicals such as vitamins A, C, E and beta-carotene, which have all been shown to help prevent cervical cancer and other forms of cancer.
  
  
• A compromised immune system related to certain illnesses such as human immunodeficiency virus (HIV) infection. Being HIV positive makes a woman's immune system less able to fight cancers such as cervical cancer.
  
  
• A family history of cervical cancer — if your mother or sister had cervical cancer — may mean you have a genetic tendency for the disease. This could be because such women are genetically less able to fight off HPV infection than other women.
  
  
• Exposure in utero to diethylstilbestrol (DES), a synthetic hormone that was prescribed to pregnant women between 1940 and 1971 to prevent miscarriages. For every 1,000 women whose mother took DES when she was pregnant, about one develops clear-cell adenocarcinoma (cancer) of the vagina or cervix. For more information on DES exposure, contact the U.S. Centers for Disease Control and Prevention (CDC), toll-free: 1-888-232-6789, or online at www.cdc.gov.
  
  
• Long-term oral contraceptive (OC) use (five or more years) may very slightly increase a woman's risk of cancer of the cervix, according to some statistical evidence. The American Cancer Society advises women to discuss the benefits of OC use versus this very slight potential risk with their health care professionals.
  

More than twice as many African-American women die from cervical cancer as Caucasian women. Additionally, Hispanic women and Native-American women have higher rates of cervical cancer than Caucasian women. Rates of cervical cancer are also increasing among Vietnamese women. Lack of access to health services (and therefore, less screening), cultural influences and diagnosis of cancer at more advanced stages are all possible reasons for these differences.

Women of all ages are at risk of cervical cancer, but half of those diagnosed are between ages 35 and 55, with the average age of diagnosis of 47 years. Regardless, it is important that even postmenopausal women continue having regular Pap tests if they still have a cervix. Even if a woman's cervix was removed during a hysterectomy (as 90 percent are), if she had a suspicious Pap before her surgery, she should continue Pap tests.

The benefits of the Pap test are clear: The overall death rate in the United States from the disease has declined by 74 percent since the introduction of the Pap test in the 1950s.

Although both the incidence and death rates of cervical cancer are going down, it is still the 12th most common cancer in women, which may be related to the epidemic of infection with HPV. According to the CDC, approximately 20 million people are currently infected with HPV. As many as 75 percent of the reproductive-age population has been infected with one or more types of HPV, and up to 5.5 million new infections occur each year.

There are more than 100 different strains of HPV, and approximately 15 types have been linked to cancer of the cervix. While most women who develop cervical cancer have HPV, not all women with the virus will develop cervical cancer. In fact, only a small proportion of women infected with HPV develop cervical cancer. Some types of HPV cause vaginal and vulvar warts; other strains cause the warts that sometimes develop on the hands or feet.

New Vaccine Offers Protection Against HPV

Now there is something women can use to protect themselves against human papillomavirus (HPV)/cervical cancer in addition to regular Pap tests and safe sex: An HPV vaccine. The FDA recently approved the vaccine — called Gardasil — for women ages 13 to 26 after clinical trials showed the vaccine is safe and 100 percent effective in preventing HPV strains 16 and 18, which cause 70 percent of cervical cancers. Gardasil, given in three injections over six months, is also 99 percent effective in preventing HPV strains 6 and 11, which cause about 90 percent of genital wart cases. Although Gardasil prevents the bulk of HPV strains, it doesn't protect against all of them, so the FDA recommends it as a complement to Pap tests. Furthermore, the vaccine does not work if a woman is already infected with one of these HPV types. It has to be given before infection.

Last medical review: 6/06
Last date updated: 1/07

Copyright 2007 National Women's Health Resource Center Inc. (NWHRC)