DIAGNOSIS, PREVENTION & TREATMENT OF HPV

Cervical testing

In March 2003, the U.S. Food and Drug Administration (FDA) approved a test manufactured by Qiagen, which is a "hybrid-capture" test, as the primary screening tool for detecting HPV cervical infection as an adjunct to Pap testing. The test may be performed during a routine Pap smear. It can detect the DNA of the 18 HPV types that most commonly affect the cervix and distinguish between "low-risk" and "high-risk" HPV types, but it cannot determine the specific HPV types.

According to the National Cancer Institute, "testing samples of cervical cells is an effective way to identify high-risk types of HPV that may be present. The FDA has approved an HPV test as a follow-up for women who have an ambiguous Pap test and, for women over the age of 30, for general cervical cancer screening. This HPV test can identify at least 13 of the high-risk types of HPV associated with the development of cervical cancer. The test can detect high-risk types of HPV even before there are any conclusive visible changes to the cervical cells."

The recent outcomes in the identification of molecular pathways involved in cervical cancer provide helpful information about novel bio- or oncogenic markers that allow monitoring of these essential molecular events in cytological smears, histological, or cytological specimens. These bio- or onco- markers are likely to improve the detection of lesions that have a high risk of progression in both primary screening and triage settings. E6 and E7 mRNA detection PreTect HPV-Proofer, (HPV OncoTect) or p16 cell-cycle protein levels are examples of these new molecular markers. According to published results, these markers, which are highly sensitive and specific, allow to identify cells going through malignant transformation.

Other testing

Although it is possible to test for HPV DNA in other kinds of infections, there are no FDA-approved tests for general screening in the United States or tests approved by the Canadian government, since the testing is inconclusive and considered medically unnecessary.

Genital warts are the only visible sign of low-risk genital HPV, and can be identified with a visual check. These visible growths, however, are the result of non-carcinogenic HPV types. Five percent acetic acid (vinegar) is used to identify both warts and squamous intraepithelial neoplasia (SIL) lesions with limited success by causing abnormal tissue to appear white, but most doctors have found this technique helpful only in moist areas, such as the female genital tract. At this time, HPV test for males are used only in research.

Prevention

Condoms offer some protection against genital infection, but any exposed skin can transmit the virus. In short, condoms are not 100% effective in preventing HPV. Genital HPV infection is the most frequent sexually transmitted disease in the world.

Vaccines

Two vaccines are available to prevent infection by some HPV types: Gardasil, marketed by Merck, and Cervarix, marketed byGlaxoSmithKline. Both protect against initial infection with HPV types 16 and 18, which cause most of the HPV associated cancer cases. Gardasil also protects against HPV types 6 and 11, which cause 90% of genital warts.

The vaccines provide little benefit to women having already been infected with HPV types 16 and 18, which includes most sexually active females. For this reason, the vaccine is recommended primarily for those women not yet having been exposed to HPV during sex. The World Health Organization position paper on HPV vaccination clearly outlines appropriate, cost-effective strategies for using HPV vaccine in public sector programs.

Both vaccines are delivered in three shots over six months. In most countries, they are approved only for female use, but are approved for male use in countries like USA and UK. The vaccine does not have any therapeutic effect on existing HPV infections or cervical lesions. In 2010, 49% of teenage girls in the US got the HPV vaccine, while in comparison around two-thirds of teens have gotten shots for meningitisand DPT vaccine.

Women should continue to seek cervical screening, such as Pap smear testing, even after receiving the vaccine. Cervical cancer screening recommendations have not changed for females who receive HPV vaccine. Without continued screening, the number of cervical cancers preventable by vaccination alone is less than the number of cervical cancers prevented by regular screening alone.

Both men and women are carriers of HPV. Possible benefits and efficacy of vaccinating men and boys are being studied.

No efficacy trials for children under 15 have been performed. Duration of vaccine efficacy is not yet answered by rigorous methodologic trials. Cervarix efficacy is proven for 7.4 years with published data through 6.4 years while Gardasil efficacy is proven for 5 years. Age of vaccination is less important than the duration of efficacy.

Condoms

The Centers for Disease Control and Prevention says that male "condom use may reduce the risk for genital human papillomavirus (HPV) infection" but provides a lesser degree of protection compared with other sexual transmitted diseases "because HPV also may be transmitted by exposure to areas (e.g., infected skin or mucosal surfaces) that are not covered or protected by the condom."

Female condoms provide somewhat greater protection than male condoms, as the female condom allows for less skin contact.

Studies have suggested that regular condom use can effectively limit the ongoing persistence and spread of HPV to additional genital sites in individuals already infected. Thus, condom use reduces the risk that already infected individuals will progress to cervical cancer or develop genital warts.

Microbicides

Ongoing research has suggested that several inexpensive chemicals might serve to block HPV transmission if applied to the genitals prior to sexual contact. These candidate agents, known as topical microbicides, are currently undergoing clinical efficacy testing. A recent study indicates that some sexual lubricant brands that use a gelling agent called carrageenan prevent papillomavirus infection in animal model systems. Clinical trial results announced at the 2010 International Papillomavirus Conference indicate that a carrageenan-based personal lubricant called Carraguard is effective for preventing HPV infection in women. The results suggest that use of carrageenan-based personal lubricant products, such as Divine No 9, Bioglide and Oceanus Carrageenan, may likewise be effective for preventing HPV infection.

Treatment

There is still no specific treatment for HPV infection. However, according to the Centers for Disease Control and Prevention, the body’s immune system clears HPV naturally within two years for 90% of cases. On the other hand, experts do not agree on whether the virus is completely eliminated or reduced to undetectable levels, and it is difficult to know when it is contagious.

 

Source: Wikipedia