Alternative Test May Soon Rival Pap Smear, Researchers Say

A test for the human papilloma virus that does not require a pelvic exam may soon rival the Pap smear as an accurate way of screening for cancer and precancerous conditions in the cervix, researchers say.

However, the test produced far more false positives than the Pap smear, causing many more women to need further testing, according to two studies in today’s Journal of the American Medical Assn.

As a screening technique, the test may be most applicable in developing countries, where pelvic exams and lab exams of cervical cells are often unavailable, said Dr. Jack Cuzick of the Imperial Cancer Research Fund in London.

But the lead author of one of the studies said the test’s rate for false positives may be much lower among U.S. women, and similar to that of the Pap smear, because they have much lower rates of sexually transmitted diseases than the African and Central American women who were studied.

“I think for women over age 35 to 40, [human papilloma virus] testing will end up, in the near future, replacing a regular Pap smear,” said the author, Dr. Thomas C. Wright Jr. of Columbia University.

The test is based on the discovery that the sexually transmitted human papilloma virus causes almost all cases of cervical cancer.

HPV infects about 40 million Americans and many more worldwide. Although most of the virus’ 80 strains cause no permanent harm, about 1% of infected people get a strain that can cause cervical cancer.

The Pap smear, which costs $25 to $35, is the most widely used screening test. It requires a skilled professional to perform a pelvic exam and scrape cells from a woman’s cervix. The cells are analyzed under a microscope.

In HPV testing, which costs $45 to $60, women can collect a sample of cervical tissue at a clinic or doctor’s office using a small brush or cotton swab. The tissue is analyzed for DNA from 13 types of virus considered to be the main culprits in cervical cancer.

Wright’s team and colleagues from AVSC International and the University of Cape Town screened and followed 1,365 black South African women between the ages of 35 and 65. The researchers found that the new test identified 37 of 56 women with high-grade cervical disease or cancer, for a detection rate of 66%.

The Pap smear identified 38 of the 56 women, a rate of 68%. But the rate for false positives for the self-collected new test was 17%, compared with only 12% for the Pap smear.