• 5/14/2007
  • web-based article
  • staff
  • CancerConsultants.com

Researchers affiliated with an international study have reported that oral infection with human papilloma virus (HPV) is associated with the development of head and neck cancers. The details of this study appeared in the May 10, 2007 issue of The New England Journal of Medicine.

Human papilloma viruses are probably the sole cause of cancers of the cervix and have been associated with cancers of the vulva, vagina, penis and rectum. Epidemiologic and molecular biology studies have also suggested that HPV infection may be associated with cancers of the head and neck. The relationship between HPV infection and head and neck cancer was reviewed in 1998 by researchers from the University of North Carolina (see related news). They reported that the overall frequency of HPV in benign and precancerous lesions ranged from 18.5% to 35.9%, depending upon the detection methodology. Using PCR, the overall prevalence of HPV in head and neck tumors was 34.5% (416 of 1,205 tumors). Type 16 HPV, which is associated with cervical cancer, was found in 40% of cases positive for HPV. They also reported variability in other sites including 59% positivity for oral cavity cancers, 43% for the pharynx, and 33% for the larynx. The frequency of HPV positivity in oral samples from healthy individuals ranged from 1% to 60%. Furthermore, age (<60 years) and sex (male) were associated with the presence of HPV in the tumor, whereas tobacco and alcohol use were not.

In the study published in 2003, researchers tested 1,670 patients from 9 countries with cancer of the oral cavity or oropharynx and compared the results with 1,732 control individuals (see related news). The researches reported that HPV DNA was detected in 3.9% of oral cavity cancers and 18.3% of cancers of the oropharynx. Patients with cancer of the tonsils were reported to have HPV in 24.7% of cases. They also reported that individuals with antibodies to HPV type 16 were at increased risk of oral cavity and oropharyngeal cancer compared to the control group with the greatest risk for cancers of the oropharynx. Their data suggested that the effects of smoking and HPV infection together were additive and not synergistic. HPV was more frequent in persons with more than one sexual partner and in those who practiced oral sex.

The current study included 100 newly diagnosed patients (86% male) with oropharyngeal cancer and 200 control patients. These authors reported that high life-time number of vaginal-sex partners (26 or more) was associated with a 3 fold risk of developing oropharyngeal cancer. A high life-time number of oral-sex partners was associated with a 3.4 fold risk of developing oropharyngeal cancer. Oropharyngeal cancer was associated with HPV type 16 and 37 other types of HPV. The researchers also detected HPV DNA in tumor specimens of 72% of patients with oropharyngeal cancer. Seropositivity to HPV 16 was highly associated with oropharyngeal cancer in patients with alcohol and tobacco exposure as well as among patients without such exposure. Tobacco and alcohol use increased the risk of oropharyngeal cancer in HPV negative patients. These authors concluded that HPV infection increased the risk of oropharyngeal cancer in alcohol and tobacco users and non-users. These authors also suggest that the more prevalent practice of oral sex may explain the increased incidence of tonsillar and base of the tongue cancers since 1973. These authors suggest that vaccination with Gardisil® should reduce the incidence of oropharyngeal cancers which would provide “the ultimate proof of causality.”

Comments:
These data confirm previous studies with more details about types of HPV involved. The speculation about the benefits of vaccination of both boys and girls to prevent oropharyngeal cancer is of major interest and should prompt debate of this subject.

Reference:
D’Souza G, Kreimer AR, Viscidi R, et al. Case-control study of human papillomavirus and oropharyngeal cancer. The New England Journal of Medicine. 2007. ;356:1944-1956.