Head and neck
cancers linked to human papillomavirus are not as lethal as such cancers
caused by other agents, according to a new study.
When controlling for other factors that affect survival,
the research team found that head and neck cancers testing positive for HPV
were 58 percent less lethal than cancers that were negative for HPV.
"Knowing that the tumor is associated with HPV is telling
the patient that the prognosis is very good," said lead author Dr. Kian Ang
of the University of Texas M.D. Anderson Cancer Center.
The researchers studied 323 patients with advanced
oropharyngeal cancer treated with a combination of radiation and
chemotherapy. HPV-positive tumors were found in 206 patients.
The difference in outcome raises the possibility that the
HPV vaccine, which acts against viral strains that cause cervical cancer and
genital warts, also may be effective at preventing HPV-positive head and
neck cancers. About 95 percent of the HPV-positive cancers studied were
caused by the strains susceptible to the vaccine.
In addition to HPV-negative status, smoking was an
independent predictor of poorer outcomes for head and neck cancer treatment.
The magnitude of the effect was similar for both HPV-negative and HPV-positive
cancers. "The risk of death significantly increased with each additional
pack-year of tobacco smoking," the authors wrote.
An accompanying editorial notes that while HPV-negative
head and neck cancers associated with tobacco use have declined, HPV-positive
head and neck cancers, likely associated with oral sex, are experiencing a
"Vaccination, if performed before exposure to the virus,
might prevent a large number of HPV-positive cases of oropharyngeal squamous-cell
carcinoma," says the editorial.
The full report, "Human Papillomavirus and Survival of
Patients with Oropharyngeal Cancer," and the editorial, "Prognostic
Implications of HPV in Oropharyngeal Cancer," were published in the New
England Journal of Medicine (2010; 10.1056/NEJMe1003607 and