Can a Virus Cause Cancer?
The term "head and neck cancer" refers to a variety of tumors that occur in the mouth, throat, larynx (voice box), nose, and sinuses. Thyroid cancer usually belongs to a separate category of head and neck cancer and is treated differently.
Excluding thyroid cancer, H&N cancers account for approximately 3 percent of all cancers in the United States and are nearly twice as common among men as they are among women.
Alcohol and tobacco use (including smokeless tobacco, sometimes called “chewing tobacco” or “snuff”) are historically the two most important causes of head and neck cancers. Treatment of head and neck cancer is dependent on the site where the tumor arises from. For instance, the recommended treatment of tumors that originate in the mouth is different than those arising in the larynx.
Certain viruses have been known to play a significant role in the development of cancer for some time. Human Papilloma Virus (HPV) is known as a cause of cervical, vaginal, and vulvar cancers in women; penile cancer in men; anal cancer, genital warts, and throat warts in both men and women. Epstein Barr Virus (EBV) is associated with nasopharyngeal carcinoma that more common in southeast Asia. Over the past decade, we have been learning about the significance of HPV as a cause of head and neck cancer. HPV infection is a well-known cause of cervical cancer in women, and it is the most common sexually transmitted infection in the world according to the National Cancer Institute. Nearly 80 million Americans are infected with HPV according to the Center for Disease Control and Prevention. The same types of HPV that infect the genital areas can infect the mouth and throat. HPV infections often resolve before they cause any health problems.
More than 15,000 HPV associated head and neck cancers are diagnosed annually.
These cancers usually occur in the oropharyngeal region – mainly in the tonsils or the base of tongue. The incidence of HPV associated head and neck cancer has been rapidly rising since the 1990’s, while tobacco related cancers are declining. The incidence of HPV associated head and neck cancer will soon surpass the number of HPV related cervical cancer cases diagnosed per year in the United States.
Historically, head and neck cancers occurred in heavy smokers and drinkers and most frequently in the 5th through the 7th decade of life. HPV associated oropharyngeal cancers present in younger individuals, more often in white males, and often in non-smokers. HPV positive cancer often presents at a higher stage with metastatic lymph nodes in the neck, but this type of cancer is usually more responsive to treatment with better overall survival.
The most widely used treatment regimen for the management of oropharyngeal cancers has been the combination of chemotherapy and radiation. Interest in surgical resection has been increasing using new technology that will allow for removal of the tumor with lower complication and with good outcome. There are new trials in progress aiming to identify the optimal treatment modality with least amount of toxicity for HPV associated cancers without compromising the outcomes. Based on the current national cancer institute guidelines, recommendations for management of HPV associated and non-HPV cancers are similar.
At this time, there are no reliable screening methods for HPV associated head and neck cancer.
The only preventive method available is vaccination prior to becoming sexually active. The new HPV vaccines -- recommended for both boys and girls age 9 to 12 -- have been shown to protect against cervical, vaginal, and vulvar cancers. The recommendations for vaccination to protect against head and neck cancer is extrapolated from this data and further research is underway. Animal tests suggest that an HPV vaccine would be preventative, and all approved vaccines are active against HPV strains 16 and 18, the subtypes of the virus that cause more than 95% of head and neck cancers.
Community adoption of the HPV vaccine in the United States remains lower than expected. One national survey suggests that less than half the girls and one third of boys receive the full recommended doses of vaccine. Decreasing the incidence of infection for now remains the only way of preventing future cancer development.
Dr. Arash Mohebati is a board certified general surgeon who completed additional fellowship training in head and neck oncologic surgery at Memorial Sloan Kettering Cancer Center. He practices with West Coast Surgical Associates -- offices in Walnut Creek, San Ramon, and Concord. Dr. Mohebati is offering visual oral cavity screenings on April 13 & 20 in recognition of Head and Neck Cancer Awareness Month. Call 925- 933-0984 to schedule your free screening appointment.
Join Dr. Mohebati and other medical experts on April 24 for a Head and Neck Cancer Seminar at the Walnut Creek Library. 6:30-8:30pm. Reservations recommended, please call 925-677-5041 x272.