HPV Test Outperforms Pap Test in Prevention of Cervical Cancer

Carcinoma of the cervix, more commonly known as cervical cancer, was a leading cause of death in women as late as the 1950s. However, with the introduction of the Pap test, death rates of cervical cancer have been reduced by as much as 99 percent in populations where women receive regular screenings. Due to the widespread use of the Pap test, the number of women who lose their lives to cervical cancer is now fewer than 4,000 per year.

The advent of the Pap test marked a major milestone in the prevention of cervical cancer. Yet, even with its overall effectiveness, failure of the test to prevent the disease can occur for various reasons, including the lack of regular screenings and proper follow up of abnormal results, as well as sampling and interpretation errors, leaving a strong need for improvement in the screening process.

Currently, women in Western countries such as the U.S. receive Pap tests in which cells are scraped from the cervix and sent off to a laboratory to be stained and microscopically inspected for abnormalities by a pathologist. This can lead to results taking several days to obtain. Although the DNA screening also requires cervical scraping, the tissue is mixed with re-agents and screened by a machine, which allows for faster results and a decrease in the need for trained pathologists to read them.

In less industrialized countries, few women are able to receive a routine screening due to the cost as well as the lack of trained pathologists. Those who do, and are told to return for follow up, are many times unable to. However, in some of these countries, women are now able to get a visualization screening in which a health worker swabs the cervix with vinegar and then uses a flashlight to screen for any spots that turn white, which may be pre-cancerous lesions. When any spots are found, they are immediately frozen off.

Now, a new DNA test that detects the human papillomavirus that causes cervical cancer may fill the gaps left by the Pap test or even someday replace it. In addition to saving more lives, scientists argue that women older than 30 years of age may be able to skip the annual Pap test and opt for the new DNA test once each 3, 5, or possibly even 10 years.

The evidence supporting this revelation comes from an eight year study of 130, 746 healthy women in India that has proven one simple screening with the DNA test to be more successful at preventing advanced cancer and saving lives that any other method currently available. The study was financed by the Bill and Melinda Gates Foundation and was published in the New England Journal of Medicine.

At the beginning of the study in 1999, the women ranging in age from 30 to 59 and coming from 497 villages were divided into four groups. The members of the control group received standard rural clinic care and were advised to go to a hospital if they wished to be screened. Another group received Pap tests, while group three received flashlight-vinegar visualization, and group four received the new DNA test. In eight years of follow-up, it was found that the visualization group experienced approximately the same rates of advanced cancer and death as the control group, with the Pap test group having about one fourth less the rates, and the DNA test group having only about half of those rates. It was also significant that none of the women having a negative DNA test died of cervical cancer. This shows that the DNA tests results are good for a number of years.

The maker of the DNA test, Qiagen, has developed a $5 version of the test with financing from the Gates Foundation to make it affordable for women in poor and middle-income countries where the cancer kills more than 250,000 women annually.

Cervical cancer is the second most common genital malignancy in the United States. It is caused by only a few of the 150 strains of the human papillomavirus. Women begin to collect strains of the virus when they become sexually active, and over 90 percent of cases clear up of their own accord within two years and therefore do not require treatment.