A new trial involving nearly 40,000 women in the Netherlands showed that testing for the human papillomavirus, or HPV allowed doctors to detect abnormal cervical cells earlier and prevent more cases of cervical cancer than administering pap smears alone.
The study was published Wednesday in the journal Lancet Oncology. It was led by a team of researchers led by Dr. Chris J.L.M. Meijer of the VU University Medical Centre in Amsterdam. They randomly assigned women ages 29-56 into two groups. The first group received an HPV test as well as a pap smear; the second group, a pap smear alone. Five years later, both groups had HPV tests and pap smears.
Results showed that the women in the group who had HPV tests at baseline had fewer cases of cervical abnormalities and cancer than women in the control group. Dual screening detected 25% more potentially cancerous lesions than the just the Pap test. Five years later, those who had had the dual screening had fewer cancers. “Our results lend support to the use of HPV DNA testing for all women aged 29 years and older,” authors of the study concluded.
Dr. Krishnansu Tewari, a gynecologic oncologist at Orange Coast Memorial Medical Center in Fountain Valley, Calif. was not surprised with the findings. “This supports what many of us have believed to have been the case for a long time now,” he said, adding that he believes HPV tests could replace pap smears completely some day.
There are many types of HPV, but only about a dozen dangerous strains lead to the development of cervical cancer and in the U.S., types 16 and 18 are responsible for the vast majority of risk, Tewari said. HPV vaccines like Gardasil protect against the only a few of the dangerous strains, but doctors can test for all of the high-risk forms by examining DNA from cells from the cervix. Currently, Tewari said, women typically receive an HPV test in one of two scenarios. Any woman who has had a minimally abnormal pap smear gets the test.
Also, women over 30 may get an HPV test to lengthen the time between their cervical cancer screenings. Such women who get negative results from a pap smear and an HPV test can wait three years, instead of the usual one, to get the next screening. This approach isn't really appropriate in younger women, who are likely to have HPV infections that ultimately will clear on their own.
In a comment article accompanying the study, Dr. Hormuzd A. Katki and Dr. Nicolas Wentzensen of the National Cancer Institute in Bethsda, wrote that the Dutch researchers' work suggests that a five year testing interval could be safe, as well.
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