Oral cancer and the human papillomavirus: Part 1
At this week’s RDH UOR, Maria Perno Goldie, RDH, MS, will teach a class as part of a workshop that will address the risks that the human papillomavirus brings and a possible link between HPV and cervical and oropharyngeal cancer. In the first of two parts, Goldie discusses the pros and cons of the HPV vaccine and explores oral cancer risks past, present, and future.
Earlier this year, the American Cancer Society (ACS) released its annual Cancer Facts & Figures.(1) The 2012 report includes some encouraging facts.
Since 1990, the incidence of some common tumors including lung, colon, and prostate cancer has declined. Meanwhile, the rate of seven malignancies, like those of the lower mouth and throat linked to human papillomavirus (HPV), is increasing.(2) The cause of this trend, which many assume is linked to people engaging in more oral sex, is not as straightforward as you might think.(3,4)
Oropharyngeal cancers refer to tumors of the tonsils and rear tongue, back of the palate and posterior walls of the throat. Like their anatomical neighbors--malignancies of the larynx, vocal cords, anterior and mid-tongue, other parts of the mouth and lips--oropharyngeal cancers arise more often in people who drink and smoke heavily. These other head and neck cancers have waned in recent years, probably because North Americans are smoking fewer cigarettes and chewing less tobacco.(5)
High-risk genotypes of human papillomavirus (HPV) can be a contributing factor to oral carcinogenesis, especially in younger individuals without known risk factors such as tobacco and alcohol. Both the Centers for Disease Control and Prevention (CDC) and the American College of Pediatrics now recommend that both girls and boys be vaccinated against HPV. There is much debate about the HPV vaccination.
I will teach a class July 19, 2013, part of a Philips Sonicare Workshop at RDH Under One Roof, where we will discuss the risks that HPV brings and the link between HPV and cervical and oropharyngeal cancer; the pros and cons of the HPV vaccine; and oral cancer risks yesterday, today, and tomorrow. We will discuss how this was 100 years ago, and the potential of it morphing in the future to be something entirely different in another 100 years. This demonstrates how medicine and diagnosis, research and transmission are changing the world faster than ever before.
In 1990, John E. Watkins theorized about the next 100 years. "Photographs will be telegraphed from any distance.” "Americans will be taller by from one to two inches.” "Wireless telephone and telegraph circuits will span the world.” "Vegetables will be bathed in powerful electric light, serving, like sunlight, to hasten their growth.” Many of his predictions came true!(6)
Years ago, aside from two known risk factors, tobacco use and drinking alcohol, health professionals were uncertain whether oral cancer was a viral or a genetic disease. Oral cancer remained a molecular black box that scientists could not open or explore. Most oral cancers were advanced by the time they were diagnosed, and mortality still remains high. Treatment options usually consisted of shrinking the tumor with radiation, followed by head and neck surgery to remove it.
Today we know that oral cancers are the sixth most common cancers in the world, and the known risk factors for oral cancer are tobacco use and alcohol consumption. Recently, infection with certain types of human papillomavirus (HPV) has been linked to oropharyngeal cancer. Research studies funded by NIH in 2010 include “Genome-wide discovery of molecular alterations in head and neck cancer” and “Comprehensive analysis of genetic alterations in oral cancer.”(7)
The leading cause of oropharyngeal cancer is from HPV.(8) A very small number of oral cavity cancers also occur from HPV, and the HPV family has almost 200 strains. Only nine are associated with cancers, and only one is strongly associated with oropharyngeal cancer, HPV16.(8)
HPV16 is often seen to manifest in the back of the throat, inside the mouth, the tonsillar pillars, and the tonsils themselves. Non-HPV tumors tend to be on the anterior tongue, the floor of the mouth and the mucosa of the cheeks. HPV16 is currently being spoken of as the second primary cause of oral cancer, and likely, will soon overpass alcohol and tobacco as being the primary cause.(9)
A 2011 study found that the proportion of oropharyngeal cancers related to HPV increased from 16.3% to 71.7% between 1984 and 2004.(10) Data presented that same year at the American Association for the Advancement of Science annual meeting suggested HPV was overtaking tobacco as the leading cause of oral cancers in Americans under the age of 50.(10) People testing positive for HPV16 oral infection have a 14 times increased risk of developing HPV+ OPC.(11)
A 2011 study: “Conclusion: Increases in the population-level incidence and survival of oropharyngeal cancers in the United States since 1984 are caused by HPV infection.”(12) The good news: “HPV-positive patients have substantially better survival compared to HPV-negative patients.”(12)
There are two alarming concerns with HPV16 oropharygeal cancer patients: the age of the victims that contract the virus; and the method in which it is often transmitted. Oral cancer contracted via the ingestion of alcohol and tobacco is most often associated with individuals who are well into life, often over the age of forty. HPV 16 varies from this immensely as it most often found in people in their 20s with no traces of alcohol or tobacco consumption, although there is an additive link between consumption of these and HPV 16. The ease of which HPV 16 is unknowingly transmitted lies in the fact that it is mainly transmitted by sexual contact.
Read Part 2 for more on this course and this topic!
Thanks to Philips Sonicare for its educational grant for this course.
11. Michl, P; Pazdera, J; Prochazka, M; Pink, R; Stosova, T (2010)."Human papillomavirus in the etiology of head and neck carcinomas"(PDF). Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia 154 (1): 9–12.
12. Chaturvedi AK, Engels EA, Pfeiffer RM, Hernandez BY, Xiao W, Kim E, Jiang B, Goodman MT, Sibug-Saber M, Cozen W, Liu L, Lynch CF, Wentzensen N, Jordan RC, Altekruse S, Anderson WF, Rosenberg PS, Gillison ML.Human papillomavirus and rising oropharyngeal cancer incidence in the United States. J Clin Oncol. 2011 Nov 10; 29(32):4294-301. doi: 10.1200/JCO.2011.36.4596. Epub 2011 Oct 3.