Vaccine May Prevent Cervical Cancer
Another question that still remains is whether people will need frequent reimmunizations, or boosters, to maintain high levels of protection against HPV. Lowy says longer studies are needed to determine how long the initial shot will last. "We don't know right now whether the protection will be for one year or 10 years," he says.
Meanwhile, other researchers reporting in the same issue of the medical journal say they've discovered that HPV16 is more complicated than originally thought. A study of more than 10,000 women in Costa Rica suggests that HPV16 has individual strains, or variants, some of which may be up to 11 times more likely to cause cancer than others. That's not to say HPV16 has much good going for it, though, since previous research indicates that having any form of HPV16 infection increases the risk of cervical cancer by more than 700 times.
Cervical cancer is diagnosed by a Pap smear. However, about 2-5% of women who have Pap smears each year get back a result that is borderline -- meaning that it could be an early stage of cancer or it could be nothing to worry about, but it can't be confirmed. Although the vast majority will have nothing wrong with them, doctors don't agree about how to handle these cases, so many women undergo excessive testing or are told to come back for repeat Pap smears in a few months.
But in another study published in the journal this month, researchers from the University of Washington, in Seattle, say a study of nearly 3,500 women with borderline Pap results confirms that the best way to handle them is to test them for HPV.
Lead author Laura Koutsky, MD, says the study "conclusively shows that women with borderline Pap smear abnormalities are better managed with an HPV DNA test than with repeat Pap screening."
Aetna US Healthcare, which decided last year to pay for HPV DNA testing for women with borderline results, says the study confirms their decision.
"Not only is the test accurate, its results are available quickly, avoiding the anxiety experienced by patients in the past," says company spokesman Arnold Cohen, MD. He adds that the test requires nothing additional from the patient, since the same specimen can be used to test for the Pap smear and HPV simultaneously.