HPV and Lung and Throat Cancer

The human papilloma virus (HPV) can infect the genital areas of the body. It can also affect the human lungs and throat epithelium, causing a condition called recurrent respiratory papillomatosis.

HPV and Recurrent Respiratory Papillomatosis

Lung infection caused by HPV is mostly due to two types, namely, Type 6 and Type 11. These account for more than 90% of all cases.

They can cause a rare disease called Recurrent Respiratory Papillomatosis (RRP). In this condition, the virus causes papillomatous (warty) growths to develop in the respiratory tract. This includes the mucosa lining the area inside the nose, mouth and lungs, and especially in the larynx (voice box).

Although these small growths are generally benign, they can occur anywhere in the respiratory tract. They can thus appear in places that compromise the breathing of someone with the condition. The condition affects both adults and children. The disease is transmitted through sexual intercourse, or sometimes to a baby born to a woman whose vagina is infected with the HPV virus.

RRP symptoms

RRP can cause hoarseness when the papillomas occur on the vocal cords or elsewhere in the voice box. It can also affect a patient’s ability to breathe. At times it can be mistaken for other respiratory diseases such as asthma.

Diagnosis of RRP

RRP is diagnosed on the basis of a history of symptoms relating to the upper respiratory tract followed by an endoscopy of the larynx, or laryngoscopy. In the procedure, an endoscope (a fiberoptic telescope) is passed into the respiratory tract of the patient through the mouth. It has a camera and a light source, which allows the operator to visualize the area and look for any growths, or take a sample of the tissue (biopsy) in the larynx for further examination.

Treatment of RRP

Patients can undergo surgery to have the growths removed. However, the growths often recur very quickly. An alternative method of treatment uses laser to remove the tumors.

Some patients may need a tracheotomy, which involves the placement of a breathing tube through the neck into the windpipe. This is usually required only in those patients who show particularly aggressive tumor growth. The procedure affects the patient’s ability to talk. Often speech rehabilitation is necessary to facilitate the recovery of speech.

HPV and Oropharyngeal Cancer

HPV strains are classified as low-risk and high-risk, based on their association with cervical cancer. Low-risk HPVs strains can cause warts in the mouth and throat. These are likely to clear up in time. However, high-risk HPVs can lead to the development of cancer of the head and neck.

One consequence of high-risk HPV infection of the throat is oropharyngeal cancer. Up to 72% of these cancers are traceable to HPV infection with a high-risk strain. The cancer usually occurs years after infection, and may require the coexistence of other carcinogens such as chewing or smoking tobacco.

Symptoms of the disease include:

• Hoarseness of voice,
• a sore throat,
• pain when swallowing,
• earache, and
• enlarged lymph nodes.

The cancer is most commonly located at the base of the tongue, that is, in the oropharynx and on the tonsils. The condition is four times more common in men than in women. In the US, about 7% of people test positive for oral HPV infection, but only 1% are infected with the high-risk strains.  

There is some suggestion that oral HPV is contracted through oral sex but studies have been contradictory. Smoking is thought to increase the risk of oral cancer following HPV infection.

Prevalence of Oropharyngeal Cancers

Oral cancers tend to have a high death rate. They are hard to detect. About 48,000 Americans are diagnosed with oral or pharyngeal cancer each year. About 9500 of them die each year. Globally the disease affects 450,000 people each year.

Lowering the Risk of Oropharyngeal Cancer

Certain foods are thought to reduce the risk of oral cancer. These include fruits, vegetables, calcium supplements, vitamin C, green tea and folate.

References

• National Institutes of Health on RRP: http://www.nidcd.nih.gov/health/voice/pages/laryngeal.aspx
• Centers for Disease Control and Prevention on oral cancer: http://www.cdc.gov/std/hpv/stdfact-hpvandoropharyngealcancer.htm
• Cancer Research UK on oral cancer: http://www.cancerresearchuk.org/health-professional/oral-cancer-risk-factors#heading-Zero