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Should HPV Test Replace the Pap Smear?
January 19, 2010
Overall good job, but didn't discuss costs or give any evidence to support a "cost-effective" claim made in the story.
Our Review Summary
Human Papilloma Virus (HPV) is the most common sexually transmitted disease and can cause cell changes that lead to cervical cancer. Each year around 12,000 women are diagnosed with cervical cancer in the US, however this number has declined significantly over the past 30 years due to widespread screening with pap smears. Screening for HPV can detect potential cases earlier in the progression of these cell changes. In theory, earlier detection and treatment could lead to fewer downstream cases of cervical cancer. However, very few positive HPV cases actually lead to cervical cancer so catching more HPV-positive screens means having to do additional tests and treatments on women who would never end up progressing to cancer anyway.
This story reports on the results from a large new study out of Italy published in Lancet Oncology comparing HPV DNA testing to traditional pap smears for cervical cancer screening. The study found that indeed the HPV DNA had a very high "callback" rate, that is the number of women testing positive and needing additional testing/treatment. In the first round of screening, similar numbers of women were found to have cancer in the two groups. However, by the second round of screening, the women in the HPV DNA group had fewer cancers than the pap smear group, presumbly because those positive for HPV had been treated earlier on in the first round. The results were statistically significant (18 cancers in the pap smear group vs 7 in the HPV DNA group).
This story does a good job of describing the current study and quotes several experts who provide valuable perspective. Most importantly, the story highlights the high false positive rate - or the high number of tests that come back positive that would never progress on to cancer. Positive results require additional testing and follow-up, which in itself isn't particularly dangerous, but could cause anxiety and requires time off work and additional costs.
The story could have been improved by discussing the costs of the tests or mentioning the costs of the additional colposcopies that result from the higher callback rate from HPV testing. Although the story claims that the HPV testing strategy is "cost-effective", it provides no evidence to support this claim. Finally, the story doesn't really quantify the benefits of HPV DNA testing in terms that are particularly useful to consumers.
Why This Matters:
It is clear that screening with HPV DNA tests will result in observing and treating more women at an earlier point in the progression from cell changes to cervical cancer. However, what is less clear is if the additional testing and treatment is worth it, not just in the cost of the tests and treatments themselves (and time off from work), but in the human cost of the anxiety it provokes.
Click on Criteria for definitions.
Clearly the HPV DNA test and pap tests are both available in the US.
The story does not discuss the costs of the tests or mention the costs of the additional colposcopies that result from the higher callback rate from HPV testing. Although the story claims that the HPV testing strategy is "cost-effective", it provides no evidence to support this claim.
The story doesn't exaggerate the prevalence or seriousnes of cervical cancer. The story appropriately mentions that the rate of the cancer has declined in the last 30 years.
The story does a good job of describing the current study and the strength of the evidence.
The story describes the potential harms of HPV DNA testing, most notably the high false positive rate - or the high number of tests that come back positive that would never progress on to cancer. Positive results require additional testing and follow-up, which in itself isn't particularly dangerous, but could cause anxiety and requires time off work and additional costs.
The story accurately represents the novelty of HPV DNA testing, which is not a new idea but as of yet in the US has not been the standard of care for cervical cancer screening on a national basis.
The story doesn't really quantify the benefits of HPV DNA testing in terms that are particularly useful to consumers. The story describes the "callback rate", or the number of women who will need additional testing after the initial screening, which makes HPV DNA testing appear as though it catches many more cancers than pap smears. However, according to the study, the number of cancers found in the first round of screening was similar in both groups (7 in the HPV DNA group, 9 in the pap smear group). It was in the second round of screening two years later that HPV DNA testing appeared to prevent cases of cervical cancer relative to pap smears (7 cancers in the HPV DNA group versus 18 in the pap smear group).
Because the story quotes multiple experts, it does not appear to rely on a press release as the sole source of information.
The story quotes several sources who provide valuable perspectives.
The story does a good job of describing the pros and cons of HPV DNA testing to pap smears, even indicating how HPV could be particularly useful in resource-poor countries.
Total Score: 8 of 10 Satisfactory
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