New test spurs debate over best cervical cancer detection

INDIANAPOLIS (AP) - For many women, an annual Pap test was part of becoming an adult. Now doctors are wondering whether that test is the best way to screen for cervical cancer, once the leading cause of cancer deaths for women in the U.S.

A relatively new test from Roche Diagnostics that looks for the presence of a virus associated with cervical cancer is in use and could replace the Pap as the front-line screening tool.

Two professional societies recently suggested that the test for human papilloma virus performs better at detecting cancer than the Pap.

But not everyone is rushing to embrace that recommendation.

Doctors agree, however, that it's critical for women to be screened regardless of which test is used. Cervical cancer strikes 12,000 women in the U.S. each year, killing 4,000. And no one disputes that HPV can be implicated in the vast majority of cervical cancer cases.

Both the traditional Pap smear and HPV test require a doctor to take a cervical swab, accompanied by a pelvic exam that includes the use of a speculum. The doctor takes a swab, dips it in a liquid base, sends it to a lab and the lab can run both tests.

Pap smears are partly dependent on human assessments and are notoriously unreliable when it comes to detecting the presence of cancer. As many as 1 in 10 abnormal tests will be read as normal, Dr. Kelly Kasper, associate clinical professor of obstetrics and gynecology at Indiana University School of Medicine, told The Indianapolis Star (http://indy.st/14WkqQV ).

So in recent years, some recommendations have supported using both tests to screen most patients.

The latest thought is that the HPV test alone wields a lot of power.

"The thing that is unique about the test ... it's either positive or negative. It's highly objective and there's no subjectivity," said Dr. Warner Huh, a professor of gynecologic oncology at the University of Alabama at Birmingham, who authored a recent report proposing that HPV testing alone be considered as an alternative to Pap testing. "When a woman undergoes cancer screening, when that test is negative, there is an extraordinarily high chance she will not get cancer within three years. You can't make the same claim with Pap testing."

Heather Banks, Indianapolis, thought that 13 years of clean annual Pap tests put her in the clear for cancer.

Then, just eight months after she had a normal Pap, she underwent another one as part of a routine pregnancy exam when she was expecting her second child.

That test came back abnormal, but her doctor told her not to worry, they would just rescreen in a few months. Six weeks after her son was born in April 2008, she had another Pap test followed by a biopsy, which was abnormal. That August, a follow-up test showed she had cervical cancer.

"When my doctor called with the diagnosis, she said over again, 'If this could happen to you, it could happen to anybody,' " said Banks, now 39. "It wasn't supposed to happen to me but it did."

Within two weeks, Banks underwent a radical hysterectomy followed by radiation and chemotherapy. For the next three years, Banks had a Pap test every three months, followed by two years of twice-annual testing.

Banks, who now advocates for better cervical cancer screening, thinks that if she had undergone HPV testing, she would have known she was at a high risk for developing cervical cancer.

"I don't know if I was ready for my son to be my last. I hadn't prepared myself through that pregnancy that he would be my last one," she said. "We're blessed with two wonderful children, but there is that piece of that being taken away from you that's hard."

Stories like Banks' provide the human experience that back up the interim report from the Society of Gynecologic Oncology and the American Society for Coloposcopy and Cervical Pathology proposing that the HPV test replace the Pap as the first screen for most women.

The Food and Drug Administration in April approved the use of Roche's cobas HPV test as a primary screening tool against cervical cancer. The test can determine whether a woman is infected with HPV and whether the type of HPV she has is one of the two responsible for 70 percent of cervical cancer cases, in other words, the really bad actors.

"It's important to know whether or not you're infected with the high-risk type,' said Dr. Alan Wright, chief medical officer of Roche Diagnostics Corp. "In any screening program, you peel away the layers of the onion of risk and peel down to higher and higher risk groups."

Under the recommendations, women could start HPV screening at age 25. Those who do not test positive for the virus will wait at least three years for their next test.

Women who test positive for the two types of the HPV virus most associated with cervical cancer should then undergo colposcopy, a procedure in which a doctor examines the cervix with an instrument that illuminates and magnifies. A sample that tests positive for a different HPV type should undergo Pap testing.

If the HPV test alone becomes widely adopted, down the road it might lead to a do-it-yourself home screening test where a woman takes her own swab, avoiding the uncomfortable speculum. If that sample comes back negative, no follow-up would be needed, experts say.

Not everyone is convinced, however, that using the HPV test as a first-line screening tool is a good idea. HPV infection is common in the population; about 80 percent of sexually active people will be infected with HPV at some point in their lives.

While a few of these infections will linger and lead to cell abnormalities that morph into cervical cancer, most resolve on their own within two years. In many cases, doctors may order additional tests when a woman comes back HPV positive when there's no reason to fear she has cancer, said Dr. David Moore, a gynecologic oncologist with Franciscan St. Francis Health.

"If you base your screening on HPV screening, you're more likely to find an abnormality that doesn't necessarily require treatment," he said. "One of our concerns is that we may be creating a lot of unnecessary anxiety for patients by detecting HPV."

In addition, switching the practice could lead more women to have unnecessary follow-up procedures, leading to higher costs, Moore said. A HPV test is more expensive than a Pap.

"The question that nobody can answer is, is that increased cost going to be justifiable in the context of are we going to be picking up many more cancerous and pre-cancerous things," he said.

Others say such fears are unfounded. Under the new proposal, a lab would run a Pap on the same sample that came back positive for HPV. Only if that test revealed abnormalities would a woman go for further testing, said IUSM's Kasper, adding she did not think that would lead to an uptick in follow-up procedures such as colposcopies.

Many gynecologists like Kasper already rely heavily on the HPV test in their cervical cancer screening practices, often using it in concert with the Pap test.

From the age of 21 to 30, younger women will be screened with Pap alone. If that test is normal, nothing more is done. If it comes back abnormal, an HPV test will be run and depending on that result, the woman will either be retested in a year or go for additional testing, said Dr. Kim Harris, an obstetrician-gynecologist at Community North Hospital.

Co-testing, using both tests at the same time, is the standard for women older than 30. Women who have a negative Pap and HPV tests will not need to be retested for five years. A woman with a negative Pap and positive HPV test for one of the two most dangerous types would go for further testing, Harris said. One who had an abnormal Pap and negative HPV would be retested in a year.

Still, Harris said, she would be open to amending her practice if new guidelines are issued.

"At the end of the day, if it's a true benefit to patients, that's how your practice changes," she said.

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Information from: The Indianapolis Star, http://www.indystar.com