What is it ?

Human papillomavirus (HPV) is a virus that often causes no symptoms but can cause cervical cancer.

Chances are you have been exposed to the human papillomavirus (HPV) and didn't even know it. In fact, it is estimated that at least 75 percent of the reproductive-age population has been infected with one or more types of genital HPV, and up to 6.2 million new infections occur each year. As many as 20 million Americans are estimated to be infected with the genital form of the virus.

The good news: In the vast majority of cases, the virus causes no symptoms or health problems and will go away on its own when a healthy immune system clears the infection. The bad news: A persistent infection with high-risk strains of HPV occurs in about 5 percent of women and causes nearly all cases of cervical cancer, which the American Cancer Society estimates affected an estimated 11,070 women

in 2008, killing about 3,870. In many ways, the issues raised by HPV infection are similar to those raised by genital herpes. Both often have no symptoms; both can cause medical problems in some women; and both have become widespread in this country. Like herpes, persistent HPV is incurable, though some forms of HPV disappear, and it is not yet known whether they completely go away or merely enter a dormant stage, like herpes.

Unlike herpes, however, HPV causes cancer in a small percentage of women and men. In addition to cervical cancer, HPV can also occasionally cause cancers of the vulva, penis, throat and tonsil area and anus.

There are more than 100 types of HPV. The HPV family of viruses is called papillomavirus because they tend to cause warts, or papillomas—benign (noncancerous) tumors. Warts may appear on the hands and feet or on the genital area. The strains of HPV that cause warts to grow on hands and feet, however, are rarely the same type that causes warts in the genital area. More than 30 strains are called genital strains and are spread through sexual contact. Only 15 are associated with cervical cancer; these are called high-risk strains (HPV 16 and 18 cause 70 percent of cancers). Two low-risk strains of HPV—HPV 6 and 11—cause 90 percent of genital warts, though they have no risk of causing cervical cancer.

The U.S. Food and Drug Administration has approved an HPV vaccine, called Gardasil, which can protect women against four HPV types—the two most common high-risk strains (HPV 16 and 18) and the two most common low-risk types (HPV 6 and 11). The vaccine, however, should be given before an infection occurs, ideally, before a girl becomes sexually active. The vaccine is approved for girls as young as nine and is routinely recommended for girls 11 and 12 years of age. It may also be given to women ages 13 to 26 who did not receive it when they were younger, but will not work against the particular HPV type if a woman is already infected with one of the four HPV types in the vaccine. (It will still work against the remaining types she has not yet been exposed to.)

Clinical trials have shown that the vaccine is safe and 100 percent effective in preventing HPV strains 16 and 18. Gardasil, given in three injections over six months, is also 99 percent effective in preventing HPV strains 6 and 11. Although Gardasil prevents two of the most serious high-risk HPV strains in women not previously exposed to them, it doesn't protect against all strains, so the FDA recommends continued screening with regular Pap tests.

The number of invasive cervical cancer cases and deaths in the United States has steadily decreased over the past several decades because of early detection by screening and treatment of cell changes. The cervical cancer death rate declined by 74 percent between 1955 and 1992. Despite the breakthrough of an HPV vaccine, the Pap test remains an important screening test to prevent cervical cancer.

In conjunction with the Pap test, the HPV test, which uses DNA-based Hybrid Capture 2 technology to detect HPV, can be used in women over age 30 to help detect HPV infection. When combined with a Pap test in women of this age group, the HPV test is better at identifying women at risk for developing cervical cancer than the Pap test alone. In addition, two new high-risk HPV tests have been approved by the FDA. One, called Cervista HPV HR, is similar to the DNA-based test and screens for the 15 high-risk strains of the virus; the other, Cervista 16/18, screens for the two HPV types most strongly associated with cervical cancer—HPV 16 and HPV 18.

How is HPV spread?

HPV is spread by skin-to-skin contact with an HPV-infected area. Infections can be subclinical, meaning the virus lives in the skin without causing symptoms. This is why many people with HPV do not know they have it or that they could spread it. For a person exposed to a partner who has a low-risk genital wart-causing strain of HPV such as HPV 6 or 11, it usually takes about six weeks to three months for genital warts to appear. However, infections with high-risk strains of HPV cause no symptoms and can only be detected on Pap or HPV tests.

Researchers already know that condoms don't always protect against the virus because the virus can grow on areas of the genitals not covered by a latex barrier.

Researchers don't know whether people infected with genital HPV but who don't have symptoms are as contagious as people with symptoms. They also don't know how much HPV is transmitted through sexual contact versus skin-to-skin contact.

Diagnosis

Because human papillomavirus (HPV) infections often cause no symptoms in men or women and are hard to identify, you must rely on your health care professional for diagnosis.

Genital warts can be flesh-colored and hidden inside the cervix, vagina, penis, scrotum or anus. They can be small or large, alone or in clusters, flat or round. They can spread along the groin or thigh or be found in the mouth.

Genital warts come in two forms-growths that can be seen with the naked eye and are on the surface of the skin and smaller, less visible growths called squamous intraepithelial lesions (SILs) that cover the cervix and require a special instrument, called a colposcope, to see.

Studies find that specific HPV types are responsible for the development of genital warts, previously known as "condyloma acuminata." Each HPV type has been numbered and divided into "high risk" or "low risk" categories depending on whether the virus is associated with the development of cancer.

For example, HPV types 6 and 11, which are usually associated with genital warts, are considered "low risk." HPV types 16, 18, 31, 33 and 35, found on the genitals and in the anus, have been linked to most HPV related cancers in both men and women.

If you notice warts, see your health care professional. You should also seek an examination if:

You see any unusual growths, bumps or skin changes on or near the penis, vagina, vulva or anus.

You experience unusual itching, pain or bleeding in the genital area.

You have a sexual partner who tells you that he or she has genital HPV or genital warts.

During your examination, your health care professional may use a colposcope, a lighted magnifying lens, to find small warts or abnormal areas. Your health care professional may also apply a vinegar solution to the genitals, which causes abnormal tissue to turn white. This doesn't hurt, but it does make it easier to see warts or precancerous lesions.

You may also have a Pap test, which was designed to identify cervical cancer in its earliest stage but can also find abnormal precancerous cells and active HPV infections.

The Pap test is a simple procedure. In the classic Pap test, a health care professional uses a special brush and/or spatula to collect cells from the cervix and place them on a glass slide, which is sent to a laboratory for evaluation. The newer and more sensitive ThinPrep Pap test uses a brush to collect the specimen, which is then put in a liquid preservative and sent to the lab for evaluation.

There are different classifications for abnormal results, but the most common is called atypical squamous cells of undetermined significance (ASCUS).

In conjunction with the Pap test, the HPV test, which uses DNA-based Hybrid Capture 2 technology to detect HPV, can also be used in women over age 30 to help detect HPV infection. When combined with a Pap test in women of this age group, the HPV test is better at identifying women at risk for developing cervical cancer than the Pap test alone. In addition, two new high-risk HPV tests have been approved by the FDA. One, called Cervista HPV HR, screens for the 15 high-risk strains of the virus. The other, Cervista 16/18, screens for the two HPV types most strongly associated with cervical cancer-HPV 16 and HPV 18.

Along with medical history and evaluation of other risk factors, the HPV test helps physicians determine what follow-up might be necessary if there is an abnormal result from a Pap test.

There is another option that provides screening for cervical cancer and HPV with one sample of cells, called a liquid-based Pap test. The cells obtained in liquid can be tested both for high-risk strains of HPV and for precancerous cell changes and cancer.

Pap Test Screening Guidelines

The American Cancer Society (ACS) recommends the following guidelines for Pap tests and early detection of cervical cancer:

All women should begin cervical cancer screening within three years of becoming sexually active or by age 21. Screenings should be done once a year if the conventional Pap test technique is used, and every two years if the liquid Pap test technique is used.

At age 30, women who have had three Pap tests in a row with normal results may be screened every two to three years. If they also have the HPV DNA test, the Pap test can be conducted once every three years.

Women age 65 to 70 and older who have had three or more normal Pap tests in a row and no abnormal test in the last 10 years may stop having cervical cancer screening, although women with the risk factors listed below should continue annual testing.

The guidelines from the American College of Obstetricians and Gynecologists (ACOG) differ slightly. ACOG recommends that screening for cervical cancer begin at age 21, regardless of sexual history. Women younger than age 21 are at very low risk of cancer. The benefits of cervical cancer screening for this age group do not outweigh the potential risks, such as unnecessary evaluation and possibly harmful treatment, according to ACOG.

ACOG also recommends that women between the ages of 21 and 29 get Pap tests every two years. Annual screening for this age group has shown little benefit compared with screening every other year. Women of any age with risk factors for cervical cancer may need to be tested more frequently.

Women who have had a total hysterectomy (removal of the uterus and cervix) may stop having cervical cancer screening unless the hysterectomy was performed because of cervical cancer or pre-cancer-related reasons. If the hysterectomy was done to treat cervical cancer, you may need more frequent Pap screenings.

Women who have had a hysterectomy in which the cervix was not removed should continue to follow screening guidelines based on their age and prior medical history, including Pap test results.

If your health care professional identifies any unusual cell changes, he or she will recommend a plan of action, depending on the result and your health history. That may include a waiting period, a repeat Pap test, a DNA-based HPV test, a colposcopy or a more thorough examination and biopsy of the abnormal area. If the Pap reveals ASCUS and the HPV test is positive, a colposcopy will be required. Colposcopy also is needed if any other more serious changes are shown by the Pap results. Further screening and treatments will depend on the results of the colposcopy. Mild dysplasia (CIN 1) should not be treated, but the Pap will be repeated in six to 12 months. For CIN 2 or CIN 3, further treatment is needed to remove the abnormal cells.

Regular Pap tests are equally important for lesbians and bisexual women who, studies find, may be less likely to seek routine health care because of the discomfort they feel discussing or revealing their sexual orientation to health care professionals. They also may not want to be screened because they feel that they are not at risk. Lesbian and bisexual women are also at risk for HPV infection and cervical cancer (for example, through prior male partners, vibrators and other sexual aids or skin-to-skin contact with an infected partner).

Talk to your health care provider about what is best for you, based on your medical history.

Treatment

There is no cure for HPV, but there are treatments for genital warts. In addition, young women may be vaccinated against four common strains of HPV with the Gardasil vaccine. For women over 26, the best defense against HPV is to learn as much as possible about the disease to try to minimize yourrisk; using condoms limiting your number of sexual contacts and continuing to have regular Pap tests are important steps to reducing risk.

Most people with HPV infections don't require treatment. Your body's immune system simply gets rid of the virus on its own. Only a small portion of women develop problems, ranging from warts to cervical cancer, that require treatment.

Most genital warts are treated because you may not like the way they look or because of symptoms-not because treatment prevents them from reforming or from you transmitting the infection to someone else. In fact, even with treatment, at least one in four people will have a recurrence within three months. Studies also find that small warts of short duration (less than one year) respond better to therapy than large warts of long duration. All wart treatments may cause mild local irritation.

Experts reviewing current genital wart treatment practices find that no single treatment is ideal for all women. They recommend that you be involved in making any treatment decisions with your health care professional. So it's important that you understand your options.

You may not even need treatment. There is no treatment available for subclinical genital HPV infection (i.e., no visible warts diagnosed by colposcopy, biopsy, acetic acid application or HPV laboratory tests). That's because there's no certain way to diagnosis subclinical genital HPV infection and no effective therapy. The infection with these low-risk strains will eventually go away on its own.

In the past, treatments for genital warts were administered by health care professionals and often caused more damage than the disease itself. Traditional treatments ranged from cryotherapy, which froze the warts with liquid nitrogen, to electrocautery, which burned off the warts. Today, there are a wide variety of treatments that can be administered by you or your health care professional.

The goal of treatment should be to remove visible genital warts and relieve annoying symptoms. No available treatment is any better than another, and no single treatment is ideal for all cases. Thus, the CDC has developed the following guidelines:

Self-applied treatments:

Podofilox (Condylox). This 0.5 or 0.15 percent solution or gel is a relatively cheap, safe, easy-to-use treatment. It is applied directly to the warts every day for three weeks or twice a day for three days, followed by four days of no therapy, for a total of three to four weeks. One review showed that the higher concentration should be used for penile warts, and the lower concentration should be used for vulvar and anal warts). Studies find that podofilox clears warts in 29 to 90 percent of patients within four to six weeks of treatment. But warts may return after treatment.

Imiquimod (Aldara). This 5 percent cream is used to treat external genital warts and perianal warts, which appear around the anus. It is safe, effective and easy to use. The cream works by stimulating the immune system to target the warts. Apply three times a week at bedtime for up to 16 weeks. Warts may recur after treatment.

People tolerate the two therapies differently, so podofilox may work better for you while imiquimod works better for someone else. Discuss with your doctor which therapy you should try. Side effects of both drugs may include tenderness, irritation and localized burning. Neither has been deemed safe to use during pregnancy.

Treatments applied by health care professionals:

Cryotherapy (freezing off the wart with liquid nitrogen). This treatment is relatively inexpensive. It is usually performed without an anesthesia, and you may experience some discomfort. You may require several treatments a week for up to six weeks to remove all warts.

Podophyllin resin 10 to 25 percent. This solution is applied once a week, typically for four weeks and must be washed off within 12 hours after application to reduce local irritation. It is more likely to cause side effects than the less-toxic, over-the-counter podofilox. There's no evidence that it's safe for use during pregnancy.

Trichloracetic acid (TCA) or bichloracetic acid (BCA) 10 to 90 percent. These are two other chemicals that are applied to the surface of the wart once a week for four consecutive weeks. These chemicals are stronger forms of the over-the-counter acids used to remove external warts. Because the procedure can be painful, most health care professionals use a topical anesthetic.

Laser therapy (using an intense light to destroy the warts) or surgery (cutting off the warts) gets rid of warts in a single office visit. However, treatment can be expensive and the health care provider must be well trained in these methods. A local or general anesthetic may be used. If not performed correctly, laser therapy can cause burning and scarring.

Interferon, a naturally occurring human protein known for its anti-viral and immunostimulating effects, can be injected directly into the warts. Usual dosage is one million units every other day for eight to 12 weeks, and side effects at these doses are usually mild. Interferon isn't effective in patients whose immune systems are suppressed.

Because HPV is a virus, your immune system plays a role in whether your warts return or not. The virus travels to the lower level of tissue where it can remain indefinitely. You should watch for recurrences, which occur most frequently during the first three months after treatment.

Eating a balanced diet, exercising regularly and avoiding illegal drugs, tobacco and alcohol are simple ways to help maintain a strong immune system.