- Journal of the National Cancer Institute
The virus that causes most cases of cervical cancer has been linked to some head and neck cancers, particularly to cancer of the tonsils, according to an article published this month in the Journal of the National Cancer Institute (JNCI, Vol. 92, No. 9). The findings are providing hope for treating a type of cancer that has not seen improvements in survival rates for the past three decades. The research by Maura Gillison, MD, and colleagues at Johns Hopkins Oncology Center, suggests some of the cancers that tested positive for the presence of the human papillomavirus (HPV) represent a distinct class of disease with a more favorable prognosis.”We found that HPV-positive HNSCC [head and neck squamous cell carcinomas] had significantly improved disease-specific survival when compared with patients with HPV-negative tumors, even after adjustment for age, lymph node status and heavy alcohol consumption,” the researchers wrote.
What the Researchers Found
Dr. Gillison and her colleagues tested tumor tissues from 253 patients with head and neck cancers and found 25 percent of the cases were HPV-positive. In 90 percent of those HPV-positive tumors, HPV16 – the type of the virus most often associated with cervical cancer – was present.Earlier research suggested a link between HPV and cancers of the tongue, tonsils and pharynx. This new study confirms a strong link between HPV and those cancers – particularly in cancer of the tonsils. “These findings are exciting because, in addition to providing a solid etiologic link between high-risk HPV infection and a subgroup of HNSCC, they promise improvements in diagnosis and also possibly treatment,” wrote David T.W. Wong, MD, and Karl Munger, MD, of Harvard Medical School, in an editorial accompanying the study. “These are pressing issues, given that the incidence and survival associated with oral cancer have essentially remained unchanged over the last 30 years.” In 1995, the International Agency for Research on Cancer concluded that high-risk HPV types 16 and 18 are carcinogenic, or cancer-causing, for humans, according to the editorial. Those types of HPV have been linked to penile, anal and vulvar cancers in addition to cervical cancer. The link between HPV and head and neck cancers had been less strong before this new study.
HPV is Sexually Transmitted
“One reason this article has elicited so much interest is undoubtedly because HPV is a sexually transmitted infection, and this new link with oral cancers suggests a link with oral sex – although questions about sexual practices were not asked of the patients in the study,” says Dawn Willis, PhD, MPH, director of research promotion and communication for the American Cancer Society.An estimated 60 percent of today’s young Americans are infected with one or more forms of HPV in young adulthood, according to Dr. Willis. “At the time of the initial infection, there is sometimes, but not always, an eruption of genital warts in either sex that later disappear,” she says. “The virus may remain latent for many years, and only a few of the infected individuals go on to develop cervical – or oral – cancers later in life. This in itself is an interesting observation, which implies that other genetic and/or environmental factors are involved.”Dr. Willis calls this new research “an excellent example of epidemiological detection work.””The authors have clearly established the association of HPV with oral cancers that have a better prognosis than those that are associated with heavy alcohol and tobacco use. And, HPV-positive oral cancers are excellent candidates for treatment with one of the therapeutic HPV vaccines that are now in clinical trials for cervical cancer,” she says.
The Promise of Vaccines
At Johns Hopkins, researchers are planning to test HPV vaccines in patients with oropharyngeal cancers – including cancers of the tonsils, the soft palate, posterior pharynx and base of the tongue, according to a news article published in JNCI. “If any of the current crop of investigational HPV vaccines prove successful, they should be available to the general public within five years,” Dr. Willis says. “Of even greater importance, there are a number of prevention trials testing a prophylactic [preventive] HPV vaccine. Such an inoculation would be invaluable in reducing the incidence and mortality of these cancers, particularly among populations where early detection is not affordable or culturally acceptable.”