New Advances in the Fight Against Cervical Cancer
Early detection and treatment are key
SUNDAY, Jan. 25, 2004 (HealthDayNews) -- Cervical cancer was once the leading cause of cancer deaths in women.
Today, because of ever-more effective screening methods, this cancer is being detected -- and cured -- at earlier and earlier stages.
That's a message worth repeating in January, which is designated Cervical Cancer Screening Month.
As with most cancers, early detection and treatment of cervical cancer are the keys to survival. An estimated 12,200 new cases of the disease are diagnosed in the United States annually, and approximately 4,100 women die from it, the federal Centers for Disease Control and Prevention says.
Virtually all cervical cancers are caused by the human papillomavirus (HPV). While many Americans will at some point be infected with this sexually transmitted virus, the vast majority of people essentially clear it from their body.
Problems arise when the virus does not resolve on its own. "Most sexually active women have had it, and it clears up," says Dr. Joseph T. Chambers, vice chairman of obstetrics and gynecology at St. Luke's Roosevelt Hospital Center in New York City.
"It's the persistence that we need to be concerned about," adds Chambers, who is also director of gynecologic oncology at Continuum Health Partners in New York City.
For 50 years, the mainstay of cervical cancer screening has been the Pap smear. In the last few years, however, there have been improvements and additions in screening techniques that give women more choices.
The Pap smear "is probably the most widely used cancer screening mechanism worldwide," says Dr. Kevin Holcomb, director of gynecologic oncology at Beth Israel Medical Center in New York City. The doctor takes a cell sample of the cervix, smears it on a slide and sends it to a lab for analysis. While the Pap does have a high failure rate, cervical cancer typically grows so slowly that another test in a year will still catch it early enough.
The liquid-based Pap test, a relatively new addition to the screening field, takes the sample in the same way but then dips it into a liquid solution instead of putting it on a slide.
"[In a traditional Pap], the cytologist has to look through millions of cells that are layered up on one another, so it's a bit like looking for a needle in a haystack," Holcomb explains. "You may also have the problem where a lot of the abnormal cells aren't transferred onto the slide. The benefit of a liquid-based test is that you have a monolayer of cells to look at. So while they're looking for the same things, it's more effective."
Liquid-based tests appear to have a higher sensitivity for detecting cervical cancer, Holcomb adds.
In other recent developments, there are new tests that hunt for the specific types of HPV known to be associated with the development of cervical cancer. (In all, there are about 100 subtypes of the virus, not all of which cause cancer).
"Certain testing that we are able to do at this point is able to not only check whether those are present but also see if there are molecular changes," Chambers says. "It gives us one other tool for trying to see not only if the individual has been exposed, but also [has the virus] in some way been integrated into the cells and caused changes."
Updated cervical cancer screening guidelines recommend that women under 30 have annual Pap smears. Those over 30 who have had three normal (or negative) Pap tests in a row can extend the interval between screenings to three years. Those 65 and older who've been screened and have been getting normal results can stop if they want. It's also not necessary to get screened if you've had your cervix removed.
In general, women should start screening three years after becoming sexually active or when they turn 21.
"In the U.S., since most people are participating in screening, we're picking up cancers at earlier and earlier stages," Holcomb says. "It's those earlier stages that are curable with surgery." And at times the surgery is minimally invasive.
One day, screening and treatment may be unnecessary.
The hot new area of research is vaccines. Recently, researchers reported good results with a vaccine that protected against HPV 16, which accounts for about 50 percent of cervical cancers. There is now a study under way with a vaccine that might be effective against more than one strain of HPV, Holcomb reports.
"That's sort of the way we're going," he says. "That may have big implications on how we screen in the future."