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Human Papilloma Virus(hpv), Genital And Throat Cancers

HPV- The Tumor Causing Viruses
Feature Article Human Papilloma Virushpv, Genital And Throat Cancers
FEB 17, 2019 LISTEN

HUMAN PAPILLOMA VIRUSES (HPV)
HPV are tumor-causing viruses that have been associated with Warts and Cancers in humans.

There are over hundred strains of HPV.
The cancer-causing HPV strains include types: 16, 18, 31, 33, 35, 39, 45, 51, 52, 58. They cause most genital and anal cancers.

Types 16 and 18 alone cause more than 2/3 of Cervical Cancers

Types 6 and 11 alone cause about 90% of Genital Warts.

TRANSMISSION
Mode of Transmission: Skin to Skin, including Vaginal, Oral and Anal sex.

Most people acquire the infection shortly after becoming sexually active

Condom use does not block HPV transmission adequately, since condoms do not cover all skin areas and condoms are not 100% protective. Condom use however, reduces the rates of infections.

Majority of infected persons have no symptoms, so they are unaware that they have the HPV infection. They can innocently, transfer their asymptomatic HPV infections to others.

The more sexual contacts one has, the higher their risk of becoming infected by the HPV.

90 % of sexually active males (80% of females) will have one or more HPV strain infections, at a point in their lives, and they will not know it.

Majority of infections go away within a couple of years; some infections may persist for years and these can cause cell changes that lead to Warts and Cancers formation.

HPV and Cancer formation
HPV enter epithelial cells. Inside the cells the viruses secret proteins: E6 and E7. The 2 proteins promote uncontrolled cellular multiplication, and prevent regular cell deaths. Gene mutations frequently occur in these cells which then become precancerous and cancerous eventually. Factors that promote cancerous transformation of infected cells include:

. Tobacco use, which increases the risk for throat cancers.

. Weakened immune system
. Oral contraceptive use, on long-term basis, promotes cervical cancer formation.

. Poor oral hygiene promotes throat cancer
It may take over 10 to 30 years of persistent infection for cervical cancers to develop. Those with impaired immunity require less than 10 years of continued carcinogenic strains of HPV infections to develop the cervical cancers

TYPES OF CANCERS (Type 16, causes most of the cancers)

. Cervical cancers (90 % of Cervical cancers are due to HPV infections.).

. Anal Cancers (90% of anal cancers)
. Throat cancers (including the distal palate, tonsils and posterior tongue) (70%).

. Penile cancers (60%)
. Vaginal and Vulva skin cancers (70%)

SYMPTOMS OF THROAT CANCERS
. Persistent sore throats
. Earaches
. Hoarseness
. Pain on swallowing
. Inexplicable weight loss
PREVENTION OF HUMAN PAPILLOMA VIRAL INFECTIONS & CERVICAL CANCERS

Condoms: Areas not covered by the condom can be infected by the virus, so condoms are not totally protective.

HPV VACCINES:
Current vaccines contain the nine carcinogenic strains that frequently cause (HPV-associated) genital cancers and warts. The vaccines provide close to 100% protection against cervical precancers and genital warts.

It is uncertain if the HPV vaccines can protect against HPV-associated Throat and Penile cancers.

HPV vaccines are most efficacious when given to persons who have never been infected with HPV. Vaccines are less efficacious at lowering the cancer risk when given to older persons, especially those older than 26 years.

It is advisable for all persons to complete their HPV vaccination series by age 26 years.

The vaccine is very effective when given to preadolescent children.

TWO-DOSE SERIES (for 9-14 year olds).

Children younger than 15 years, 2 inoculations of the vaccine offer the same protection as three inoculations. The second dose is given after 6-12 months. Adolescents who receive their two doses less than 5 months apart, require a 3rd dose.

THREE DOSE SERIES (those 15 years and older)

For older adolescents and young adults aged 15-26 years, three inoculations of the HPV vaccine are given at 0, 2, and 6 months.

Side effect of vaccination: Pain, redness and soreness at the inoculation site. Muscle aches, fever and headaches, occasionally.

CERVICAL CANCER SCREENING.

  1. Pap test (Pap smear) for cervical cancer

Pap test is a cytology test that looks for changes, caused by HPV, in the cells of the cervix, which could lead to cancers.

In female less than 21 years of age, precancerous transformation of infected cells does not often lead to cancer. Therefore, the PAP test is not recommended for females less than 21 years old.

Those who have their uterus/ cervix removed surgically do not need PAP tests.

Recommendation: Irrespective of vaccination status all females,

. Age 21 to 29: PAP test every three years.

. Age 30 to 65: PAP test every 3 years; Every 5 years if the HPV test is done simultaneously.

These recommendations do not apply to women diagnosed previously with high grade precancerous lesions cervical lesion or cervical cancer, and individuals with impaired immunity

PAP test results are read as either Normal or Abnormal. Abnormal Pap test require a follow up Colposcopy

  1. HPV GENOTYPING tests (For women aged 25 years and older.)

The HPV test looks for the presence of the two HPV types that cause most cervical cancers: type 16 and 18 HPVs, and the presence of 12 other high-risk HPV types in cervical fluids. Results are interpreted as either positive or negative for the presence of HPVs in the cells

Positive screening test results for HPV types 16 or 18 is followed up with a Colposcopy

A negative test result for type 18 and 16, but Positive for one of the 12 other high-risk HPV types requires a follow up PAP test, to determine the need for a Colposcopy.

TREATMENT
. No medication is available for treating HPV infections that have not been associated with abnormal cell changes

. Treatment is available for: genital warts, precancerous cervical and other sites lesions. Available treatment methods include:

. Freezing to destroy the tissues (cryosurgery)
. Electrosurgery Using a hot wire loop to remove cervical tissue

. Laser surgery to destroy cervical tissues
. Cone biopsy of cervix and cervical canal.

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