Detecting High-Risk HPV in Older Women
Women all know about the Pap test. It's the screening device that looks for precancerous lesions on the cervix. Jodi McKinney, 41, of Bethlehem Township, N.J., has had a Pap smear every year for two decades.
"Everything always came back negative, so you know everything was fine," McKinney says.
Or so she thought. But about a year ago, her gynecologist suggested adding another test that the American Cancer Society and the American College of Obstetricians and Gynecologists (ACOG) recommend.
The HPV test can detect an active infection with one of the high-risk strains of the virus. McKinney says she had heard about the HPV vaccine, but she had never heard about the test for the virus until a nurse handed her an informational brochure.
"I had no idea what it was until I saw the pamphlet and read about it," she says. "Then I consented right away to have it done — luckily."
Even though her Pap tests had come back normal, McKinney's HPV test was positive. That meant she was infected with at least one strain of the virus that sometimes leads to cancer.
Pap smears miss up to 40 percent of precancerous lesions. Dr. Mamie Bowers, McKinney's gynecologist, says that reading Pap smears can be tricky.
"They're a test that relies on a human being to read a slide" and interpret what they see, Bowers says. "They're not as reliable as we'd like them to be."
Over time, Pap smears eventually pick up most slow-growing cancers. But the benefit of the new HPV test is that it tells you right away if you're infected with a virus that could cause the cancer.
In McKinney's case, when a follow-up biopsy revealed she had precancerous lesions, she opted for surgery to remove them.
"I was very fortunate," she says.
The HPV test was first introduced in 1999. But only now is it starting to be used as a primary screening tool. Kaiser Permanente, a large HMO based in California, has found that giving both the Pap and the HPV test to women 30 and older helps detect more cases of precancerous disease.
Dr, Ruth Shaber of Kaiser Permanente is a big fan of using the two tests in combination.
"We have found women who otherwise would have gone through the system with normal Pap smears, not ever suspecting that there's something wrong," says Shaber.
Not Recommended for Women Under 30
The American Cancer Society recommends waiting until women are 30 or older before adding the HPV test to the Pap smear. That is because nearly half of all women in their 20s have transient HPV infections that their immune systems can fight off.
"Most of the women who come into contact with HPV, in fact 80 percent, will spontaneously clear the infection over two years," says Dr. Tom Wright of Columbia University.
"So the women we're worried about are the ones who have persistent infections," Wright says. These are the women who need to be watched closely.
Annual Pap Smears May Not Be Necessary
Women who are negative on both the Pap test and HPV test are at such low risk for cervical disease, says Wright, that "we can safely tell them that they don't need to be re-screened for another three years."
This means scores of women are now being told to give up the annual Pap smear. Instead, the three-year interval is recommended. Many patients are reluctant to follow this advice at first.
"That's taking some education," says Dr. Mamie Bowers. "Women say, 'What? I don't have to do this every year?'"
Gynecologists do check for other potential problems.
"The full annual exam involves a full pelvis exam and a breast exam," says Bowers. So gynecologists still want their patients to come in for a visit every year.
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