HPV Infection Linked to Increased Risk of Oral Cancer From Tobacco Usage

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HPV Infection
The human papillomavirus infection (HPV) has been linked to increased risk of oral cancer for those who use tobacco products according to a recent study. The paper was published in the Journal of the American Medical Association (JAMA) on Oct. 8.

The study was conducted by researchers from the Johns Hopkins University School of Medicine. the lead author  was Dr. Carole Fakhry, MD, MPH, a researcher and Assistant Professor specializing in ear, nose and throat conditions (ENT) at Baltimore’s Johns Hopkins University School of Medicine. Additional  authors include Dr. Maura L. Gillison, MD, Ph.D, Professor at The Ohio State University Comprehensive Cancer Center College of Medicine, Columbus, Ohio and Gypsyamber D’Souza, Ph.D, MS, MPH, Associate Professor at The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD.

According to the study, the incidence of oral cancers in the United States is greatly increased by several forms of tobacco usage, including all forms of tobacco smoking, the use of smokeless tobacco and environmental exposure due to second-hand smoke. This particular form of the human papillomavirus infection is termed HPV-16, and is a sexually transmitted disease.

Normally, HPV-16 is transmitted through standard vaginal sexual intercourse, sometimes causing cervical cancer in woman. This current Johns Hopkins study investigates the prevalence of contracting the human papillomavirus infection through oral sexual relations, rather than the more common vaginal sexual intercourse.

The risk factors for contracting an HPV-16 infection increase by up to 34 percent, with even minimal tobacco usage. A HPV infection causes cancer if left untreated, and the majority of persons with any type of HPV infection are asymptomatic, meaning there are no visible symptoms. Symptomatic HPV infections usually manifest themselves in most cases as genital warts. HPV-16 and HPV-18 are said to be responsible for upwards of 70 percent of all cervical cancer cases in the world.

The study was quick to point out that smoking did not directly cause the HPV-16 infection or oral and throat cancers associated with an HPV-16 infection, only that the two instances were directly related. Oral and throat cancers can be directly linked to the use of tobacco even in the absence of a HPV infection. The relationship between contracting an HPV-16 infection and then developing oral cancer is what the study seeks to inform.

Study participants numbered 6,887, with 34.2 percent of that total being smokers, fully 2,012 candidates, with 81.3 percent of those individuals reported to be cigarette smokers specifically. Results were obtained from the 63 study participants that were smokers and were identified as currently having an HPV-16 infection, through the use of urinalysis and blood sample analysis.

Blood analysis results indicated a 31 percent increased risk factor for oral cancer based on cotinine levels of study participants who smoked 3 cigarettes daily. Additionally, researchers discovered through urinalysis that risk factors increased to 68 percent when subjects smoked as little as four cigarettes daily. Cotinine in the blood is a direct result of tobacco use.

The relationship between smoking and contracting an HPV-16 infection is not readily evident and researchers, “don’t fully understand,” the exact relationship between the two, said lead study author Dr. Carole Fakhry, MD, MPH. She also indicated that users of tobacco products appear more likely to contract an HPV-16 infection after having oral sexual relations with a person already having the virus and, “are less likely to get rid of the infection,” because they use tobacco and tobacco related products.

According to the Centers for Disease Control and Prevention (CDC) there are over 40 different strains of the human papillomavirus that cause HPV infections, most of which cause 70 percent of all cervical cancers each year. These different strains also cause oropharynx, which is the information the study mentioned here previously illustrated. For calendar year 2012, the most recent year that CDC statistics are available, more than 12,000 women in the U.S. were diagnosed with cervical cancer, with more than 4,000 deaths attributed to the infection, and the cancers they cause.

The CDC estimates that more than 33,000 HPV related cancers happen in the U.S. each year, with roughly one-third of those cancers (12,600) occurring in men. Generally speaking, women are at increased risk for cervical cancer from a HPV infection, while men are at increased risk for acquiring an oral cancer from a human papillomavirus infection. Fully 60 percent of all throat related cancers are linked to an HPV infection.

The risk factors that link contracting oral cancer from a HPV infection are increased dramatically by the use of tobacco products, as the study attempts to portray. The CDC estimates that 80 percent of sexually active people age 14 to 44 have had oral sex with a person of the opposite gender. There is a vaccine available to prevent HPV infections.

By Jim Donahue

JAMA Study
CDC – HPV and Cancer
CDC – Cervical Cancer
CDC – HPV-Associated Cancers Statistics

Image courtesy of James Gathany License