Since the most common form of cervical cancer starts withpre-cancerous changes, there are 2 ways to stop this disease from developing. The first way is to is to find and treat pre-cancers before they become cancerous, and the second is to prevent the pre-cancers.

Finding and treating pre-cancerous changes

A well-proven way to prevent cervix cancer is to have testing (screening) to find pre-cancers before they can turn into invasive cancer. The Pap test (or Pap smear) is the most common way to do this. If a pre-cancer is found it can be treated, stopping cervical cancer before it really starts. Most invasive cervical cancers are found in women who have not had regular Pap tests.

The American Cancer Society recommends the following guidelines for early detection:

• All women should begin cervical cancer testing (screening) 3 years after they start having sex (vaginal intercourse). A woman who waits until she is over 18 to have sex should start screening no later than age 21. A conventional (regular Pap) test should be done every year. If a liquid-based Pap test is used instead, testing should be done every 2 years.

• Beginning at age 30, many women who have had 3 normal Pap test results in a row may be tested less often, every 2 to 3 years. Either the conventional (regular) Pap test or the liquid-based Pap test can be used. Some women should continue getting tested yearly -- such as women exposed to DES before birth, those with a history of treatment for a pre-cancer, and those with a weakened immune system (such as from HIV infection, organ transplant, chemotherapy, or chronic steroid use).

• Another reasonable option for women over 30 (who have normal immune systems and no abnormal Pap results) is to get tested only every 3 years with a Pap test plus the HPV DNA test (see below for more information on this test). The Pap test used can be either the regular or the liquid-based Pap test.

• Women 70 years of age or older who have had 3 or more normal Pap tests in a row and no abnormal Pap test results in the last 10 years may choose to stop having cervical cancer testing. Women with a history of cervical cancer, DES exposure before birth, HIV infection, or a weakened immune system should continue to have testing as long as they are in good health.

• Women who have had a total hysterectomy (removal of the uterus and cervix) may also choose to stop having cervical cancer testing, unless the surgery was done as a treatment for cervical cancer or pre-cancer. Women who have had a hysterectomy without removal of the cervix (a supra-cervical hysterectomy) need to continue cervical cancer screening. They should continue to follow the guidelines above.

Some women believe that they can stop having Pap tests once they have stopped having children. This is not correct. They should continue to follow American Cancer Society guidelines.

Although the Pap test has been more successful than any other screening test in preventing a cancer, it is not perfect. One of the limitations of the Pap test is that it needs to be examined by humans, so an accurate analysis of the hundreds of thousands of cells in each sample is not always possible. Engineers, scientists, and doctors are working together to improve this test. Because some abnormalities may be missed (even when samples are examined in the best laboratories), it is not a good idea to have this test less often than American Cancer Society guidelines recommend.

Making your Pap tests more accurate

You can do several things to make your Pap test 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 douche or use tampons, birth control foams, jellies, or other vaginal creams or vaginal medicines for 48 hours before the test.

Pelvic exam versus Pap test

Many people confuse pelvic exams with Pap tests. The pelvic exam is part of a woman's routine health care. During a pelvic exam, the doctor looks at and feels the reproductive organs, including the uterus and the ovaries and may do tests for sexually transmitted disease. Pap tests are often done during pelvic exams, but you can have a pelvic exam without having a Pap test. A pelvic exam without a Pap test will not help find cervical cancer at an early stage or abnormal cells of the cervix. The Pap test is often done at the start of the pelvic exam, after the speculum is placed. To do a Pap test, the doctor must remove cells from the cervix by gently scraping or brushing it with a special instrument. Pelvic exams may help find other types of cancers and reproductive problems, but only Pap tests give information on early cervical cancer or pre-cancers.

How the Pap test is done

Cytology is the branch of science that deals with the structure and function of cells. It also refers to tests to diagnose cancer by looking at cells under the microscope. The Pap test (or Pap smear) is a procedure used to collect cells from the cervix for cervical cytology testing.

The health care professional first places a speculum inside the vagina. The speculum is a metal or plastic instrument that keeps the vagina open so that the cervix can be seen clearly. Next, using a small spatula, a sample of cells and mucus is lightly scraped from the exocervix (the surface of the cervix that is closest to the vagina). A small brush or a cotton-tipped swab is then inserted into the cervical opening to take a sample from the endocervix (the inside part of the cervix that is closest to the body of the uterus). There are 2 main ways to prepare the cell samples so that they can be examined under a microscope in the laboratory.

Conventional cytology

One method is to smear the sample directly onto a glass microscope slide, which is then sent to the laboratory. All cervical cytology samples were handled in this way for at least 50 years. This method works quite well and is relatively inexpensive, but it does have some drawbacks. One problem with this method is that the cells smeared onto the slide are sometimes piled up on each other, making it hard to see the cells at the bottom of the pile. Also, white blood cells (pus), increased mucus, yeast cells, or bacteria from infection or inflammation can hide the cervical cells. Another problem is that if the slides are not treated (with a preservative) right away, the cells can dry out. This can make it difficult to tell if there is something wrong with the cells. If the cervical cells cannot be seen well (because of any of these problems), the Pap smear may need to be repeated.

Liquid-based cytology

Another method is to put the sample of cells from the cervix into a special preservative liquid (instead of putting them on a slide directly). This is sent to the lab. Technicians then use special lab instruments to spread some of the cells in the liquid onto glass slides to look at under the microscope. This method is called liquid-based cytology, or a liquid-based Pap test. The liquid helps remove some of the mucus, bacteria, yeast, and pus cells in a sample. It also allows the cervical cells to be spread more evenly on the slide and keeps them from drying out and becoming distorted. Cells kept in the liquid can also be tested for HPV. Using liquid-based testing reduces the chance that the Pap test will need to be repeated, but it does not find more pre-cancers than a regular Pap test. The liquid-based test is also more likely to find cell changes that are not pre-cancerous but that will need to be checked out further -- leading to unnecessary tests. This method is also more expensive than the usual Pap test.

Another way to improve the Pap test is by using computerized instruments to spot the abnormal cells on the slides. An instrument to do this has been approved by the FDA to read Pap tests first (instead of them being examined by a technologist). It is also approved by the FDA for rechecking Pap test results that were read as normal by technologists. Any smear identified as abnormal by this instrument would then be reviewed by a doctor or a technologist.

Computerized instruments can find abnormal cells that technologists sometimes miss. Most of the abnormal cells found in this way are in rather early stages, such as atypical squamous cells but sometimes high-grade abnormalities missed by human testing can be found. Scientists do not know yet whether the instrument can find enough high-grade abnormalities missed by human testing to have a real impact on preventing invasive cervical cancers. Automated testing also increases the cost of the cervical cytology testing.

For now, the best way to detect cervical cancer early is to make certain that all women are tested according to American Cancer Society guidelines. Unfortunately, many of the women most at risk for cervical cancer are not being tested often enough or at all.

How Pap test results are reported

The most widely used system for describing Pap test results is The Bethesda System (TBS). This system has been revised twice since it was developed in 1988: first in 1991 and, most recently, in 2001. The information that follows is based on the 2001 version. The general categories are:

• negative for intraepithelial lesion or malignancy,
• epithelial cell abnormalities, and
• other malignant neoplasms.

Negative for intraepithelial lesion or malignancy

This first category means that no signs of cancer, pre-cancerous changes, or other significant abnormalities were found. Some specimens in this category appear entirely normal. Others may have findings that are unrelated to cervical cancer, such as signs of infections with yeast, herpes, or Trichomonas vaginalis (a microscopic parasite), for example. Some cases may also show reactive cellular changes, which is the way cervical cells respond to infection or other irritation.

Epithelial cell abnormalities

The second category, epithelial cell abnormalities, means that the cells of the lining layer of the cervix show changes that might be cancer or a pre-cancerous condition. This category is divided into several groups for squamous cells and glandular cells.

The epithelial cell abnormalities for squamous cells are called:

• Atypical squamous cells (ASCs); these are further divided into ASC-US and ASC-H
• Squamous intraepithelial lesions (SILs); these are separated into low-grade SILs and high-grade SILs
• Squamous cell carcinoma

Atypical squamous cells: This category includes atypical squamous cells of uncertain significance (ASC-US). This term is used when there are cells that look abnormal, but it is not possible to tell (by looking at the cells under a microscope) if the cause is infection or irritation, or if it is a pre-cancer. Most of the time, cells labeled ASC-US are not pre-cancer. Some doctors will recommend repeating the Pap test after 6 months. Some doctors use the HPV DNA test to decide whether or not to do a colposcopy. If a high-risk type of HPV is detected, the doctor is likely to order a colposcopy. (Colposcopy is discussed in more detail in the section "Other tests for women with abnormal cervical cytology results.")

If the results of a Pap test are labeled ASC-H, it means that a high grade SIL is suspected. Colposcopy is recommended.

Squamous intraepithelial lesions (SILs): These abnormalities are divided into low-grade SIL and high-grade SIL. High-grade SILs are less likely than low-grade SILs to go away without treatment. High-grade SILs are also more likely to eventually develop into cancer if they are not treated. Treatment can cure all SILs and prevent true cancer from developing. A Pap test cannot tell for certain if a woman has a high- or low-grade SIL. It merely fits the result into one of these abnormal categories. Any patient with an SIL should have colposcopy. The need for treatment is based on the results of the biopsies obtained during colposcopy. Since most SILs are positive for HPV, HPV testing is not used to determine the need for colposcopy in a woman with SIL on a Pap.

Squamous cell carcinoma: This result means that the woman is likely to have an invasive squamous cell cancer. Further testing will be done to be sure of the diagnosis before treatment can be planned.

The Bethesda System also describes epithelial cell abnormalities for glandular cells.

Adenocarcinoma: Cancers of the glandular cells are reported as adenocarcinomas. In some cases, the pathologist examining the cells can suggest whether the adenocarcinoma started in the endocervix, in the uterus (endometrium), or elsewhere in the body.

Atypical glandular cells: When the glandular cells do not look normal, but have features that do not permit a clear decision as to whether they are cancerous, they are called atypical glandular cells. The patient usually will have more testing if her cervical cytology result shows atypical glandular cells.

The HPV DNA test

As mentioned earlier, the most important risk factor for developing cervical cancer is infection with HPV. Doctors can now test for the types of HPV that are most likely to cause cervical cancer (high-risk types) by looking for pieces of their DNA in cervical cells. The test is done similarly to the Pap test in terms of how the sample is collected, and in some cases can even be done on the same sample. The HPV DNA test is used in 2 different situations.

• The FDA has approved the HPV DNA test to be used in combination with the Pap test to screen for cervical cancer in women over 30 years old (see American Cancer Society screening guidelines above). It does NOT replace the Pap test. Women in their 20s who are sexually active are much more likely (than older women) to have an HPV infection that will go away on its own. For these younger women, results of this test are not as significant and may be more confusing. For this reason, the HPV DNA test is not recommended as a screening test in women under 30. For more information, see the American Cancer Society document, What Every Woman Should Know About Cervical Cancer and the Human Papilloma Virus.

• The HPV DNA test can also be used for women of any age who have slightly abnormal Pap test results (ASC-US) to find out if they might need more testing or treatment (see next section).

Other tests for women with abnormal cervical cytology results

The Pap test is a screening test, not a diagnostic test. An abnormal Pap test result means that other tests will need to be done to find out if a cancer or a pre-cancer is actually present. The tests that are used include colposcopy (with biopsy) and endocervical scraping. These tests are used for a Pap test result of SIL or atypical glandular cells. If a biopsy shows a pre-cancer, doctors will take steps to keep an actual cancer from developing.

Doctors are less certain about what to do when the Pap test result shows atypical squamous cells (ASC). In deciding what to do, doctors take into account your age, your previous Pap test results, whether you have any cervical cancer risk factors, whether you have remembered to have Pap tests done in the past, and whether the test result is ASC-H or ASC-US. Women 20 years old or younger with Pap test results that show ASC-US are likely to be observed without treatment. For women at least 21 years of age with ASC-US, experts recommend either a colposcopy, a repeat Pap test in 6 months, or HPV DNA testing. If the woman is HPV positive, colposcopy will be done. For ASC-H, many doctors will recommend colposcopy and biopsy.

Colposcopy

If you have certain symptoms that suggest cancer or if your Pap test shows abnormal cells, you will need to have a test called colposcopy. In this procedure you will lie on the exam table as you do with a pelvic exam. A speculum will be placed in the vagina to help the doctor see the cervix. The doctor will use a colposcope to examine the cervix. The colposcope is an instrument (that stays outside the body) that has magnifying lenses (like binoculars). It lets the doctor see the surface of the cervix closely and clearly. The doctor will apply a weak solution of acetic acid (similar to vinegar) to your cervix to make any abnormal areas easier to see.

Colposcopy is not painful, has no side effects, and can be done safely even if you are pregnant. Like the Pap test, it is rarely done during your menstrual period. If an abnormal area is seen on the cervix, a biopsy will be done. For a biopsy, a small piece of tissue is removed from the area that looks abnormal. The sample is sent to a pathologist to look at under a microscope. A biopsy is the only way to tell for certain whether an abnormal area is a pre-cancer, a true cancer, or neither.

Cervical biopsies

Several types of biopsies are used to diagnose cervical pre-cancers and cancers. If the biopsy can completely remove all of the abnormal tissue, it may be the only treatment needed.

Colposcopic biopsy: For this type of biopsy, first the cervix is examined with a colposcope to find the abnormal areas. Using a biopsy forceps, a small (about 1/8-inch) section of the abnormal area on the surface of the cervix is removed. The biopsy procedure may cause mild cramping, brief pain, and some slight bleeding afterward. A local anesthetic is sometimes used to numb the cervix before the biopsy.

Endocervical curettage (endocervical scraping): Sometimes the transformation zone (the area at risk for HPV infection and pre-cancer) cannot be seen with the colposcope. In that situation, something else must be done to check that area for cancer. This means taking a scraping of the the endocervix by inserting a narrow instrument (called a curette) into the endocervical canal (the passage between the outer part of the cervix and the inner part of the uterus). The curette is used to scrape the inside of the canal to remove some of the tissue that is lining the endocervical canal. This tissue sample is sent to the laboratory for examination. After this procedure, patients may feel a cramping pain, and they may also have some light bleeding.

Cone biopsy: In this procedure, also known as conization, the doctor removes a cone-shaped piece of tissue from the cervix. The base of the cone is formed by the exocervix (outer part of the cervix), and the point or apex of the cone is from the endocervical canal. The transformation zone (the border between the exocervix and endocervix) is contained within the cone. This is the area of the cervix where pre-cancers and cancers are most likely to start. The cone biopsy can also be used as a treatment to completely remove many pre-cancers and some very early cancers. Having a cone biopsy will not keep most women from getting pregnant, but if a large amount of tissue has been removed, women may have a higher risk of giving birth prematurely.

There are 2 methods commonly used for cone biopsies: the loop electrosurgical excision procedure (LEEP; also called large loop excision of the transformation zone [LLETZ]) and the cold knife cone biopsy.

• Loop electrosurgical procedure (LEEP, LLETZ): In this method, the tissue is removed with a thin wire loop that is heated by electrical current and acts as a scalpel. For this procedure, a local anesthetic is used, and it can be done in your doctor's office. It takes only about 10 minutes. You may have mild cramping during and after the procedure, and mild-to-moderate bleeding may persist for several weeks.

• Cold knife cone biopsy: This method uses a surgical scalpel or a laser instead of a heated wire to remove tissue. It requires general anesthesia (you are asleep during the operation) and is done in a hospital, but no overnight stay is needed. After the procedure, cramping and some bleeding may last for a few weeks.

How biopsy results are reported

The terms for reporting biopsy results are slightly different from The Bethesda System for reporting Pap test results. Pre-cancerous changes are called cervical intraepithelial neoplasia (CIN) or, rarely, dysplasia, instead of squamous intraepithelial lesion (SIL). The terms for reporting cancers (squamous cell carcinoma and adenocarcinoma) are the same.

How women with abnormal Pap test results are treated to prevent cervical cancers from developing

If an abnormal area is seen during the colposcopy, your doctor can remove it with a loop electrosurgical procedure (LEEP or LLETZ) or a cold knife cone biopsy. Other options include destroying the abnormal cells with cryosurgery or laser surgery.

During cryosurgery, the doctor uses a metal probe cooled with liquid nitrogen to kill the abnormal cells by freezing them.

In laser surgery, the doctor uses a focused beam of high-energy light to vaporize (burn off) the abnormal tissue. This is done through the vagina, with local anesthesia.

Both cryosurgery and laser surgery can be done in a doctor's office or clinic. After cryosurgery, you may have a lot of watery brown discharge for a few weeks.

These treatments are almost always effective in destroying pre-cancers and preventing them from developing into true cancers. You will need follow-up exams to make sure that the abnormality does not come back. If it does, the treatments can be repeated.

Things to do to prevent pre-cancers

Avoid being exposed to HPV

You can prevent most pre-cancers of the cervix by avoiding exposure to HPV. Certain types of sexual behavior increase a woman's risk of getting HPV infection, such as:

• having sex at an early age
• having many sexual partners
• having a partner who has had many sex partners
• having sex with uncircumcised males

Delay sex

Waiting to have sex until you are older can help you avoid HPV. It also helps to limit your number of sexual partners and to avoid having sex with someone who has had many other sexual partners. Remember, HPV does not always cause warts or any other symptoms; even someone infected with HPV for years may have no symptoms. Someone can have the virus and pass it on without knowing it.

Use condoms

Condoms provide some protection against HPV. One study found that when condoms are used correctly they can lower the HPV infection rate by about 70% if they are used every time sex occurs. Condoms cannot protect completely because they don't cover every possible HPV-infected area of the body, such as skin of the genital or anal area. Still, condoms provide some protection against HPV, and they also protect against HIV and some other sexually transmitted diseases. Condoms (when used by the male partner) also seem to help the HPV infection and cervical pre-cancers go away faster.

Don’t smoke

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

Get vaccinated

Vaccines have been developed that can protect women from HPV infections. So far, a vaccine that protects against HPV types 6, 11, 16 and 18 (Gardasil) and one that protects against types 16 and 18 (Cervarix) have been studied. Cervarix was recently approved (in 2009) for use in the United States by the FDA, while Gardasil has been approved for use in this country since 2006. In October 2009, the FDA also approved the use of Gardasil in males to prevent genital warts. Both vaccines require a series of 3 injections over a 6-month period. Side effects are usually to be mild. The most common one is short-term redness, swelling, and soreness at the injection site. Rarely, a young woman will faint shortly after the vaccine injection. Cervarix is approved for use in girls and young women ages 10 to 25 years, while Gardasil is approved for those 9 to 26 years old.

In clinical trials, both vaccines prevented cervical cancers and pre-cancers caused by HPV types 16 and 18. Gardasil also prevented genital warts caused by HPV types 6 and 11.. Both Gardasil and Cervarix only work to prevent HPV infection -- they will not treat an infection that is already there. That is why, to be most effective, the HPV vaccine should be given before a person starts having sex.

In 2009, the Federal Advisory Committee on Immunization Practices (ACIP) published recommendations for HPV vaccination. It recommended that females aged 11 to 12 routinely receive HPV vaccination with the full series of 3 shots. Females as young as age 9 may also receive the vaccine at the discretion of their doctors. ACIP also recommended women ages 13 to 26 who have not yet been vaccinated get "catch-up" vaccinations. For the prevention of cervical cancers and pre-cancers, either of the 2 vaccines, Cervarix or Gardasil, may be used. For the prevention of cervical cancers, cervical cancers, and genital warts, ACIP recommends the use of Gardasil.

These vaccines should be given with caution to anyone with severe allergies. Women with a severe allergy to latex should not take the Cervarix vaccine, and those with a severe allergy to yeast should not receive Gardasil.

The American Cancer Society guidelines recommend that the cervical cancer vaccine be routinely given to females aged 11 to 12 and as early as age 9 years at the discretion of doctors. The Society also agrees that catch-up vaccinations should be given to females up to age 18.

The independent panel making the Society recommendations found that there was not enough proof that catch-up vaccination for all woman aged 19 to 26 years would be beneficial. As a result, the American Cancer Society recommends that women aged 19 to 26 talk with their health care provider before making a decision about getting vaccinated. They should discuss the risks of previous HPV exposure and potential benefit from vaccination before deciding to get the vaccine. Research has shown that it is effective in producing an immune reaction to the HPV types in the vaccine and also reduces cervical cancers and pre-cancers in those vaccinated. These vaccines have also been studied in older women and males As new information on Cervarix, Gardasil, and other new products becomes available, these guidelines will be updated.

Both types of cervical cancer vaccines are expensive -- costing about $375 for the full series of injections (not including the doctor's fee or the cost of giving the injections). It should be covered by most medical insurance plans (if given according to ACIP guidelines). It should also be covered by government programs that pay for vaccinations in children under 18. Because this cost is so high, you may want to check your coverage with your insurance company before getting the vaccine.

It is important to realize that the vaccine doesn’t protect against all cancer-causing types of HPV, so routine Pap tests are still necessary. One other benefit of the Gardasil vaccine is that it protects against the 2 viruses that cause 90% of genital warts.

For more information on the vaccine and HPV, please see our document, Human Papilloma Virus: Questions and Answers.

Last Medical Review: 09/14/2009
Last Revised: 01/19/2010