Cervical cancer is one of the most common cancers that affect a woman's reproductive organs. Various strains of the human papillomavirus (HPV), a sexually transmitted infection, are responsible for most cervical cancer cases.

When exposed to HPV, a woman's immune system typically prevents the virus from doing harm. In a small group of women, however, the virus survives for years before it eventually converts some cells on the surface of the cervix into cancer cells. Half of cervical cancer cases occur in women between ages 35 and 55.

Thanks largely to Pap test screening, the death rate from cervical cancer has decreased greatly over the last 40 years. Still, every year more than 10,000 women in the United States are diagnosed with invasive cervical cancer, and nearly 4,000 die of cervical cancer.

Early cervical cancer generally produces no signs or symptoms. As the cancer progresses, these signs and symptoms may appear:

• Vaginal bleeding after intercourse, between periods or after menopause
• Watery, bloody vaginal discharge that may be heavy and have a foul odor
• Pelvic pain or pain during intercourse

These factors increase your risk of cervical cancer:

• Many sexual partners. The greater your number of sexual partners — and the greater your partner's number of sexual partners — the greater your chance of acquiring HPV.
• Early sexual activity. Having sex before age 18 increases your risk of HPV. Immature cells seem to be more susceptible to the precancerous changes that HPV can cause.
• Other sexually transmitted diseases (STDs). If you have other STDs — such as chlamydia, gonorrhea, syphilis or HIV/AIDS — you have a greater chance of also having acquired HPV.
• A weak immune system. Most women who are infected with HPV never develop cervical cancer. However, if you have an HPV infection and your immune system is weakened by another health condition, you may be more likely to develop cervical cancer.
• Cigarette smoking. The exact mechanism that links cigarette smoking to cervical cancer isn't known, but tobacco use increases the risk of precancerous changes as well as cancer of the cervix.

There currently isn't any way to determine which women have immune systems that make them more susceptible to cervical cancer. That's why simple and inexpensive Pap tests are important.

During a Pap test, your doctor brushes cells from your cervix — the narrow neck of the uterus — smears them onto a glass slide and sends the slide to a lab. A technician called a cytotechnologist examines the slide for abnormal cells. A doctor who specializes in cellular abnormalities (pathologist) further reviews the slides that contain abnormal cells before making a final diagnosis.

A newer approach to Pap screening uses a liquid to transfer the sample of cells to the lab. Your doctor collects the cells in exactly the same way, but then he or she rinses the instruments in a special liquid, which preserves the cells for examination later. When this sample reaches the lab, a technician prepares a microscopic slide that's more easily interpreted than is the traditional method.

In nearly all cases, a Pap test allows for the detection of abnormal cells. This is the precancerous stage, when the abnormal cells (dysplasia) exist only in the outer layer of the cervix and haven't invaded deeper tissues. If untreated, the abnormal cells may convert to cancer cells, which may spread in various stages into the cervix, the upper vagina, the pelvic areas and to other parts of your body. Cancer or precancerous conditions that are caught at the pre-invasive stage are rarely life-threatening and typically require only outpatient treatment.

HPV DNA test
Your doctor also may use a lab test called the HPV DNA test to determine whether you are infected with any of the 13 types of HPV that are most likely to lead to cervical cancer. Like the Pap test, the HPV DNA test involves collecting cells from the cervix for lab testing. It can detect high-risk strains of HPV in cell DNA before changes to the cells of the cervix can be seen.

The HPV DNA test isn't a substitute for regular Pap screening, and it's not used to screen women younger than 30 with normal Pap results. Most HPV infections in women of this age group clear up on their own and aren't associated with cervical cancer.

Pre-invasive stage
Treatment of cervical cancer in the pre-invasive stage, when it has affected only the outer layer of the lining of the cervix, may include:

• Conization. This simple surgery involves removing with a scalpel a cone-shaped piece of cervical tissue where the abnormality is found.
• Laser surgery. This operation uses a narrow beam of intense light to kill cancerous and precancerous cells.
• Loop electrosurgical excision procedure (LEEP). This technique uses a wire loop to pass electrical current, which cuts like a surgeon's knife and remove cells from the mouth of the cervix.
• Cryosurgery. This technique involves freezing and killing cancerous and precancerous cells.
• Hysterectomy. This major surgery involves removal of the cancerous and precancerous areas, the cervix and the uterus.

According to the American Cancer Society (ACS), all women with pre-invasive cervical cancer can be cured with appropriate treatment.

Invasive stage
Many women are treated successfully for invasive cervical cancer and live full, productive lives. According to the ACS, the five-year survival rate is more than 90 percent when the cancer is still confined to the cervix.

Treatment may involve:

• Hysterectomy. Surgery is usually recommended for younger women because it often can preserve one or both ovaries along with their estrogen production, which is important in maintaining bone strength. A simple hysterectomy — removal of the cancer, the cervix and the uterus — is typically an option only when there is an invasion of less than 3 millimeters (mm) into the cervix. A radical hysterectomy — removal of the cervix, uterus, part of the vagina and lymph nodes in the area — is the standard surgical treatment when there's an invasion of greater than 3 mm into the cervix and no evidence of tumor on the walls of the pelvis.
• Radical trachelectomy. Women with early-stage cervical cancer may be able to preserve their fertility by having this surgical procedure, which involves removing the cervix and the lower part of the uterus. Enough of the uterus is left in place that you may be able to carry a child. Lymph nodes in the pelvis are also removed during this procedure to determine whether the cancer has spread.
• Radiation. High-energy rays shrink tumors by killing the cancer cells. The radiation destroys the ability of cancer cells to reproduce. Premenopausal women will experience menopause because their ovarian functions are destroyed by the radiation.
• Chemotherapy. These anti-cancer drugs enter your bloodstream and travel throughout your entire body. Chemotherapy enhances the effects of radiation in the treatment of cervical cancer.

Some women with early-stage cervical cancer are treated with a simple hysterectomy or radical trachelectomy alone. However, women with more advanced cancer and women who are at high risk of recurrence are usually treated with a radical hysterectomy, a regime of combined radiation and chemotherapy, or a combination of all of these approaches.

In June 2006, the Food and Drug Administration (FDA) approved the first drug treatment for late-stage cervical cancer. The drug — Hycamtin — is the first approved medication to treat cervical cancer that's unlikely to respond to surgery or radiation therapy. Hycamtin is used in combination with chemotherapy. The drug was originally approved in 1996 for treating ovarian cancer and in 1998 to treat small cell lung cancer.

HPV can spread through skin-to-skin contact with any infected part of the body — but using a condom every time you have sex can significantly reduce your risk of contracting HPV, according to a 2006 study.

In addition to using condoms, the best ways to prevent cervical cancer are to:

• Delay first intercourse
• Have fewer sexual partners
• Avoid smoking

Pap test guidelines
Routine Pap tests are the most effective way to detect cervical cancer in the earliest stages. Work with your doctor to determine the best schedule for Pap tests. Current guidelines suggest:

• An initial Pap test within three years of when you begin having sex or at age 21, whichever comes first.
• From ages 21 to 29, a regular Pap test every year or a liquid-based test every two years.
• From ages 30 to 69, a regular Pap test every two years or a liquid-based test every three years if you've had three normal Pap tests in a row.
• From age 70 on, you may stop having Pap tests if you've had three or more normal tests in a row and no abnormal results in the last 10 years.

If you're at high risk of cervical cancer, you'll need more frequent Pap tests. If you've had a hysterectomy, talk with your doctor about whether to continue getting Pap tests. If the hysterectomy was done for a noncancerous condition, such as fibroids, you may discontinue routine Pap tests, but not pelvic exams. If the hysterectomy was done for a precancerous or cancerous condition, your vaginal canal still needs to be checked for abnormal changes.

Cervical cancer vaccine
A new vaccine known as Gardasil offers protection from the most dangerous types of HPV — the virus that causes most cervical cancers. The Food and Drug Administration (FDA) approved the vaccine in June 2006. The national Advisory Committee on Immunization Practices recommends routine vaccination for girls age 11 and 12, as well as girls and women ages 13 to 26 if they haven't received the vaccine already. The vaccine is most effective if given to girls before they become sexually active.

Although the vaccine could prevent up to 70 percent of cervical cancer cases, it can't prevent infection with every virus that causes cervical cancer. Routine Pap tests to screen for cervical cancer remain important.