July 29, 2009 -- As a group, blacks with head and neck cancer have a much lower survival rate than whites with the disease, and now groundbreaking new research helps explain why.
The study sheds new light on the racial differences in head and neck cancer presentation and outcomes, and experts say that it should change the way all patients with the disease are initially evaluated and how many are treated.
“It is the most important development in head and neck cancer that I have seen in the last 30 years,” Scott Lippman, MD, of the University of Texas M.D. Anderson Cancer Center said in a news conference held today.
Survival 5 Times Greater in HPV-Positive Patients
Lippman, who was not involved with the study, was talking about the identification of human papilloma virus (HPV) as a major survival indicator in patients with a specific type of head and neck cancer.
When researchers examined outcomes by race for subgroups of head and neck cancer, they found that blacks had a poorer survival for only one -- oropharyngeal cancer, which includes the throat, tonsils, and base of the tongue.
And when they looked specifically at oropharyngeal cancer, they found a striking difference in survival among patients who were and were not infected with human papilloma virus 16 (HPV 16) -- one of the sexually transmitted HPV viruses that also causes cervical cancer.
HPV-positive patients treated with chemotherapy and radiation were five times more likely to survive than those with HPV-negative disease, lead author Kevin Cullen, MD, of the University of Maryland tells WebMD.
White patients had nine times the HPV infection rate of blacks, with just 4% of black patients evaluated testing positive for the virus, compared to 34% of whites.
Cullen says the fact that HPV-positive throat cancer has such a good prognosis and the fact that blacks are far more likely to have HPV-negative disease may largely explain the head and neck cancer survival disparity amongst the two groups.
He noted that survival among HPV-positive patients is as high as 90%; survival rates are very low for HPV-negative disease.
Oral Sex Important Risk Factor
So why are HPV infection rates much higher for white head and neck cancer patients than for black patients?
The answer may come down to differences in the way the two groups begin their sexual lives, Otis Brawley of the American Cancer Society tells WebMD.
Becoming infected with HPV through oral sex may protect against future genital infection and visa versa, Brawley says.
So people who are infected through oral sex are at risk for developing HPV-positive throat cancer and those infected through genital sex may be protected, he suggests.
The link between HPV and throat cancer has only been recognized for a few years, but it is very real, the experts say.
HPV infection is now estimated to be the cause of as much as 50% of oropharyngeal cancers being diagnosed today.
“This is very different from 20 or 30 years ago when the risk factors for this disease were primarily tobacco and alcohol,” Lippman said.
Implications for Treatment, Vaccination
Cullen, Brawley, and Lippman said that head and neck patients, especially those with throat cancer, should be tested for HPV.
“The good news is, patients who are HPV-positive can be reassured that they will do well with chemotherapy and radiation,” Cullen says.
Chemotherapy and radiation have become the treatments of choice for head and neck cancer, but Cullen says it may not be the right approach for patients with HPV-negative oropharyngeal disease.
“This should make us rethink which patients are appropriate for chemotherapy and radiation and who might be better served by surgery and other approaches,” he says.
The findings may also have implications for who gets vaccinated to prevent HPV infection.
The vaccine is recommended for pre-teen girls only, but Brawley says an alarming increase in oropharyngeal cancers may lead to its wider use.
Even though HPV-positive patients have a good prognosis, vaccination might mean that they would never get the cancer in the first place, he says.