MONDAY, April 3, 2006 (HealthDay News) -- A test to detect the virus that causes cervical cancer is more sensitive, more effective and easier to conduct than the traditional Pap smear.
So, the test, for human papillomavirus (HPV), should be adopted as the worldwide standard, said the authors of a study appearing in the April 3 issue of the International Journal of Cancer.
"We are reporting many studies here, which are being brought together," said study author Jack Cuzick, the John Snow professor of epidemiology at the Centre for Epidemiology, Mathematics and Statistics at Cancer Research UK, Queen Mary School of Medicine, in London. "Hopefully, seeing the overwhelming effect of all results together will change practice."
Other experts were also heartened by the findings.
"We are learning the viral implications of female genital tract malignancies," said Dr. Jay Brooks, chairman of hematology/oncology at the Ochsner Clinic Foundation in Baton Rouge, La. "In the future, this will be the way that individuals will be screened for the risk of many genital malignancies."
Cuzick estimated that HPV testing would achieve a reduction of 50 percent above and beyond that achieved by the conventional Pap test in the United Kingdom. In the developing world, the impact would be greater. "If this test could be applied there as well, 80 to 90 percent of cancers and deaths might be prevented."
Cervical cancer causes 300,000 or more deaths worldwide each year, most in areas where there is no screening at all.
In the United States, some 10,400 new cases will be diagnosed this year, and 3,700 women will die from the disease.
An estimated 20 million men and women in the United States are infected with HPV. For most, HPV shows no symptoms and goes away on its own. However, the virus can lead to cervical cancer in some women.
Right now, early detection is the only way to forestall cervical cancer, although researchers are close to finalizing a vaccine against HPV.
The current gold standard test for cervical cancer involves collecting cells from the cervix via a Pap smear, then examining them under a microscope for abnormalities. The technique is known as cytology.
While the method has unquestionably reduced the incidence of cervical cancer, it does have limitations. For instance, results depend on collecting high-quality samples and on the interpretation of changes within cells, which can be subjective.
Several studies have already demonstrated that HPV testing is more sensitive than cytology at detecting the changes in cervical cells that can lead to cancer.
The new study looked at data from these studies, all of them conducted in North America or Europe. In total, the studies involved more than 60,000 women who had received both cytology and HPV testing.
Overall, HPV testing was extremely sensitive (96 percent), regardless of the age of the patient. Cytology had a sensitivity rate of 53 percent, but this varied among different age groups.
HPV testing, on the other hand, was less specific for women under 35. Specificity refers to the rate of false-positive readings.
The authors felt it was "very realistic" to adopt this test worldwide.
"Cheap forms of HPV testing are well into development to deal with cost issues in the developing world," Cuzick said. "In the developed world, the main barrier is inertia and an unfounded belief in the accuracy of cytology, which hopefully this paper will put to bed."
The study did not look specifically at cervical cancer testing in the developing world, but Cuzick said that "the value of HPV [testing] is likely to be even greater" there.
The International Agency for Research on Cancer recently issued a statement that HPV testing could reduce the incidence and mortality from cervical cancer, proclaiming that it is at least as effective as cytology. The English Cervical Screening Advisory Committee has accepted this statement and agreed that the HPV test could be used by the national screening program. The idea would be to use the HPV test first and follow it up with cytology for women who test positive.
"My belief is that we have enough evidence now to begin large-scale demonstration projects involving up to 1 million women per country," Cuzick said.
More information
The American Cancer Society can tell you more about cervical cancer.
