Smoking is down, but oral cancer is up. Dr. Torbjorn Ramqvist and Dr. Tina Dalianis of Sweden reported that a slow epidemic of human papillomavirus (HPV) is responsible for the increase in oropharyngeal squamous cell carcinoma, which includes the most common cancers of the oral cavity and nearby tissues of the throat and nose. It is important to distinguish HPV positive cancers from the more traditional ones associated with smoking and alcohol, according to Ramqvist and Dalianis, because the HPV type has a much higher survival rate. Therefore, it should be treated with more attention to minimizing chronic side effects of treatment, including difficulty in swallowing or talking, dry mouth, and necrosis of the jawbone.
The poor survival rate of oropharyngeal cancer associated with smoking and alcohol have led to intense treatment with surgery, radiation, and chemotherapy. Damage to the salivary glands and other structures can produce significant impairments to the quality of life of survivors. Such intense therapy may not be appropriate for HPV positive cancers.
There are over 100 types of HPV, found in skin warts and mucous tissues. HPV is most commonly known as the cause of cervical cancer, and a vaccine is available. The DNA from this virus has been detected in 45 percent to 100 percent of oropharyngeal squamous cell carcinomas, depending on the location of the cancer, the techniques used for the testing, and the time period and country of the study. Approximately 90 percent of the HPV positive samples contained HPV type 16, which is included in the vaccine.
A larger study was reported by Dr. K. Kian Ang and 14 other authors in The New England Journal of Medicine. These researchers confirmed that patients with HPV-positive oropharyngeal tumors have a much better prognosis than those with HPV-negative tumors.
Oral sex and open-mouth kissing may be responsible for the new epidemic of cancer, according to Ramqvist and Dalianis. They commented, “we need to know if future vaccination against HPV infection should include both women and men.” In Ang's study, men outnumbered women for both HPV-positive and HPV-negative oropharyngeal cancer.
Ang recommended that future clinical trials should be designed to consider HPV-positive and HPV-negative oropharyngeal cancers separately.
References:
1. Ramqvist T, Dalianis T, “Oropharyngeal cancer epidemic and human papillomavirus”, Emerging Infectious Diseases 2010 November; 16(11): 1671-7.
2. Ang KK et al, “Human papillomavirus and survival of patients with oropharyngeal cancer”, The New England Journal of Medicine 2010 July1; 363: 24-35.
Linda Fugate is a scientist and writer in Austin, Texas. She has a Ph.D. in Physics and an M.S. in Macromolecular Science and Engineering. Her background includes academic and industrial research in materials science. She currently writes song lyrics and health articles.