Screening programs for cervical cancer should include a test for the human papillomavirus (HPV), according to a new study from The Netherlands.
In women over 30, a screening program that used an HPV test in addition to a pap smear test detected pre-cancerous lesions earlier and prevented more cervical cancers from developing than a screening program that included only a pap smear test, the study found.
In addition, a negative test for HPV was more accurate than a negative pap smear. “If you are negative, then it's a real negative,” said study researcher Chris Meijer of the VU University Medical Centre in Amsterdam.
The study gives researchers more confidence that “testing for HPV truly provides…better protection for women being screened for cervical cancer,” said Eduardo Franco, a cancer epidemiologist at McGill University, in Montreal, who was not involved in the study.
In the United States, the pap smear is the primary tool used for cervical cancer screening. Screening that also includes the HPV test is acceptable for women over 30, but it is not universally recommended.
Because the study was conducted in The Netherlands, it's not clear whether the results are applicable to other countries, but Franco said the findings argue for more widespread use of HPV testing in the United States.
Such a screening program would likely use HPV testing as the primary screening tool in women over 30. A follow-up pap smear would be used only in women with a positive HPV test, Franco said.
The study will be published online tomorrow (Dec. 15) in the journal the Lancet.
Cervical cancer kills 273,000 women worldwide every year, and nearly all cases are caused by HPV, a virus transmitted through sexual activity.
The new study included nearly 45,000 women between the ages of 29 and 56.
Participants were screened twice. At the first screening, the women were randomly assigned to receive either HPV testing plus a pap smear (HPV group), or only a pap smear (control group). Five years later at the second screening, all participants received HPV testing and a pap smear.
The first screening revealed 96 precancerous lesions, known as cervical intraepithelial neoplasia grade 2 (CIN2)in the HPV group, compared with65 in the control group. Women with the precancerous lesions were treated according to Dutch guidelines.
The second screening showed that four women in the HPV group had developed cervical cancer, compared with14 in the control group. There were also fewer cases of a more serious pre-cancerous lesion, known as CIN3, in the HPV group than in the control group.
In addition, women who tested negative for HPV at the first screening were less likely to develop cancer five years later than were women who initially had a “normal” pap smear.
The increased protection against cervical cancer, and against serious lesions, in the HPV group is due to the increased detection of early pre-cancers, the researchers said.
The study suggests women over 30 who test negative for HPV and have a normal pap smear can safety wait five years before they have another HPV test, Hormuzd Katki and Nicolas Wentzensen, from the National Cancer Institute in Bethesda, Maryland, wrote in an editorial accompanying the study.
One argument against routine HPV testing is that the test will lead to over diagnoses: it will find pre-cancers that will not further develop and become cancer, and only lead to unnecessary testing and worry. But Katki and Wentzensen pointed out that there were only 32 more cases of precancerous lesions in the group that underwent HPV tests than those who underwent pap smears.
“We expect that almost every woman who tests negative for HPV, irrespective of country or screening protocol, has an extremely low risk of cancer over 3 or 5 years,” the researchers wrote.
However, women who test positive for HPV will need to be carefully managed, so they are not subjected to unnecessary procedures, including biopsies, they said.
Women younger than 30 are not thought to benefit as much from HPV testing because too many of them will test positive for HPV, Franco said. Thirty years old is about the age when HPV infections that were acquired with the onset of sexual activity begin to wan as they are cleared by the immune system.
Franco said new guidelines for cervical cancer screening in the United States are in the works. The guidelines, sponsored by the American Cancer Society, the American Society for Colposcopy and Cervical Pathology, Centers for Disease Control and Prevention, the National Institutes of Health will be released early next year, he said.
Pass it on:Screening with the HPV test and the pap smear is more effective at preventing cervical cancer than is screening with the pap smear alone in women over 30.
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