The American Cancer Society issued its recommendations for using the new vaccine against cervical cancer -- recommendations that veer from those of other groups when it comes to vaccinating women over 18.
The guidelines, published in the American Cancer Society's journal, CA: A Cancer Journal for Clinicians, call for routinely vaccinating all girls aged 11 to 12.
They add that the vaccine, called Gardasil, may be given to girls as young as 9.
Girls 13 to 18 should be given a "catch-up" vaccine if they never received their vaccine, or did not complete the three-shot series.
However, unlike the CDC and the American College of Obstetricians and Gynecologists, the American Cancer Society (ACS) does not recommend routine vaccination for women 19 to 26.
"We don't believe the research is there among women 19 to 26 to justify universal vaccine recommendation," says ACS guidelines co-author Mark Einstein, MD, director of clinical research at Montefiore Medical Center and Einstein College of Medicine in New York City.
More than 11,000 new cases of cervical cancer will be diagnosed in 2007, with more than 3,600 deaths, according to ACS estimates.
The new cervical cancer vaccines, combined with new information about the viral causes of cervical cancer, "present an unprecedented opportunity for global cervical cancer prevention," say the ACS guidelines.
Gardasil protects against cervical cancer by preventing infection by the human papillomavirus (HPV), the leading cause of cervical cancer.
HPV is a sexually transmitted virus, with dozens of strains.
But, according to ACS, two of those strains -- HPV 16 and 18 -- are responsible for up to 70 percent of all cervical cancers.
Gardasil protects against four strains of HPV -- HPV 16 and 18, as well as HPV 6 and 11, which account for 90 percent of genital warts -- providing the woman has not been previously exposed.
And, says Einstein, therein lies the important caveat for women 19 to 26.
"Studies show most women in this age group have had four or more sex partners, meaning they have likely already been exposed to HPV," he says.
Since the vaccine will not work on those already infected, Einstein says it was important for ACS to hold back from routinely recommending it in this age group.
"The recommendation is for women in this age group to talk to their doctor about whether or not the vaccine can benefit them. But the research does not justify universally recommending the vaccine," says Einstein.
Stephanie V. Blank, MD, a gynecologic oncologist at the NYU Cancer Institute in New York City, disagrees.
While women aged 19 to 26 may benefit less from the vaccine, the shift away from routine recommendations is likely to have more of a financial than a medical advantage, Blank says.
"Giving the vaccine to a woman who has already been exposed is not going to harm her -- and, in fact, it may help her, since it's unlikely that she would have been exposed to all four of the cancer-related strains of HPV for which the vaccine provides protection," says Blank.
Indeed, Blank tells WebMD that as long as a woman knows she needs to follow up with regular screening Pap tests, whether she has been vaccinated or not, "Those aged 19 to 26 should also be encouraged to get vaccinated." (All cervical cancers are not caused by HPV.)
Not for Those Over 26
Currently, there are no HPV vaccine studies on women over age 26. The FDA has approved Gardasil only for girls and women age 9 to 26.
Also, there is not enough evidence to say whether booster shots will be needed throughout a woman's life.
NYU's Blank says it's important to note that while most cervical cancer is related to HPV, not all HPV infections -- even those caused by strains 16 and 18 -- will result in cervical cancer.
"Most HPV infections, even potentially carcinogenic ones, resolve or become undetected in a year or less," says Blank. Many women never even know they were infected.
Moreover, she says, even persistent HPV infections don't always progress to precancerous lesions.
According to the ACS report, 75 percent of all low-grade lesions, and up to 90 percent of high-grade lesions, resolve withouttreatment -- and never go on to cause cancer.
When cancer does occur, the process involves several steps that could take as long as 20 years. But, in most cancers, those steps begin with HPV infection -- one reason doctors are hopeful vaccinating women at a young age will pay off.
"If you can vaccinate a woman before she becomes sexually active, you will help knock out step one -- HPV acquisition -- and that hopefully means knocking out cervical cancer," says Einstein.
As good as that sounds, Einstein adds that it will take many years before we learn whether or not the vaccine will be that effective.
By Colette Bouchez, reviewed by Louise Chang, MD
SOURCES: Mark Einstein, MD, director of clinical research, Montefiore Medical Center and Einstein College of Medicine, New York City. Stephanie V. Blank, MD, gynecologic oncologist, NYU Cancer Center, New York City. Press Materials/ HPV Vaccine, American Cancer Society. Saslow, D. CA: A Cancer Journal for Clinicians, January/February 2007; vol 57: pp 7-28. American College of Obstetricians and Gynecologists: "ACOG Releases Revised Recommendations for Women's Health Screenings and Care." CDC: "HPV Questions and Answers." WebMD Medical News: "Cervical Cancer Vaccine Approved."