What is HPV?
HPV, also called human papilloma virus, is a group of more than 150 related viruses. More than 40 of these viruses can be easily spread through direct skin-to-skin contact during vaginal, anal, and oral sex.
What is the association between HPV infection and cancer?
High-risk HPV infection accounts for approximately 5 percent of all cancers worldwide. However, most high-risk HPV infections occur without any symptoms, go away within 1 to 2 years, and do not cause cancer. These transient infections may cause cytological abnormalities, or abnormal cell changes, that go away on their own.
o However, high-risk or oncogenic HPV, can persist for many years. Persistent infections with high-risk HPV types can lead to more serious cytological abnormalities or lesions that if left untreated may progress to cancer.
o At least a dozen high-risk HPV types have been identified. Two of these, HPV types 16 and 18, are responsible for the majority of HPV-caused cancers of the cervix, anus and oropharynx.
How does high-risk HPV cause cancer?
HPV infects epithelial cells. These cells, which are organized in layers, cover the inside and outside surfaces of the body, including the skin, the throat, the genital tract, and the anus. Because HPV is not thought to enter the blood stream, having an HPV infection in one part of the body should not cause an infection in another part of the body.
Once HPV enters an epithelial cell, the virus begins to make proteins. Two of the proteins made by high-risk HPVs interfere with normal functions in the cell, enabling the cell to grow in an uncontrolled manner and to avoid cell death.
Many times these infected cells are recognized by the immune system and eliminated. Sometimes, however, these infected cells are not destroyed, and a persistent infection results. As the persistently infected cells continue to grow, they may develop mutations that promote even more cell growth, leading to the formation of a high-grade lesion and, ultimately, a tumor.
Researchers believe that it can take between 10 and 20 years from the time of an initial HPV infection until a tumor forms. However, even high-grade lesions do not always lead to cancer.
Throat and Tonsil Cancer
HPV infections have been found to cause cancer of the oropharynx, which is the middle part of the throat including the soft palate, the base of the tongue, and the tonsils.
The incidence of HPV-associated oropharyngeal cancer has increased during the past 20 years, especially among men. It has been estimated that, by 2020, HPV will cause more oropharyngeal cancers than cervical cancers in the United States.
HPV-infected individuals who develop cancer generally receive the same treatment as patients whose tumors do not harbor HPV infections, according to the type and stage of their tumors.
Treatment
Primary cancers of the oropharynx can be treated with surgery, chemotherapy, radiation, or combined surgery and radiation therapy depending on the stage of the cancer as well as patient preference.
Surgical treatment in our practice is performed as a two part staged procedure; the first is part is a neck dissection, followed at a later time by Trans Oral Robotic Surgery (TORS) resection of the primary throat tumor. Both of these procedures are done under general anesthesia and depending on the pathology results and staging of the cancer, a referral to a Radiation Oncologist for adjuvant treatment may be needed.