Some women have a new option for cervical cancer screening — and it doesn't necessarily involve a Pap test — according to updated guidelines from a government-appointed panel of experts.
The guidelines, from the U.S. Preventive Services Task Force (USPSTF), say that women ages 30 to 65 can be screened for cervical cancer with a test for "high risk" strains of the human papillomavirus (HPV) every five years, without undergoing a simultaneous Pap test.
Previously, the USPSTF recommended "co-testing" — or the use of both the HPV test and the Pap test — every five years, for women ages 30 to 65. While "co-testing" is still one recommended way to screen for cervical cancer, it is a less preferable method, because its use may result in women undergoing more tests and procedures overall, compared with either HPV testing or Pap testing alone, the new guidelines say. [5 Cervical Cancer Facts]
Alternatively, women ages 30 to 65 can be screened for cervical cancer with the Pap test alone every three years, according to the guidelines.
Although some women now have more choices for cervical cancer screening, the most important thing is for them to get screened: Efforts to carry out the guidelines should "focus on ensuring that women receive adequate screening, regardless of which strategy is used," the USPSTF said.
"Regular screening with any method will lead to lower cervical cancer rates," Dr. Joy Melnikow, director of the UC Davis Center for Healthcare Policy and Research, said in a statement. "Our biggest challenge is reaching women who have not been screened," added Melnikow, who led one of the studies on HPV testing that informed the new guidelines.
High-risk strains of HPV are spread through sexual contact and cause about 90 percent of cervical cancers. Although most HPV infections clear up on their own, in some cases, the virus lingers and may eventually lead to cervical cancer.
Both the HPV test and the Pap test look at cells from a woman's cervix, according to the National Cancer Institute. In a Pap test, the cells are analyzed to see if they are cancerous, while in an HPV test, the cells are tested for HPV infection. (Co-testing can be done with just one cervical swab.)
The guidelines, which are published today (Aug. 21) in the journal JAMA, are an update to the USPSTF's previous recommendations on cervical cancer screening, which were issued in 2012. A draft of the new guidelines was released in September 2017, and they have now been finalized.
Here are some important things to know about the updated guidelines:
What are the cervical cancer screening guidelines now?
For women under age 30 and over age 65, the USPSTF's guidelines haven't changed. They are as follows:
- Women under age 21 should not be screened for cervical cancer.
- Women ages 21 to 29 should undergo screening every three years using a Pap test, also called "cervical cytology." (HPV testing isn't recommended for women ages 21 to 29 because, in this age group, HPV infection is common and is often cleared by the immune system.)
- Women over age 65 do not need to be screened for cervical cancer if they are up to date on their screening, their tests in the previous 10 years were negative and they don't have other risk factors for cervical cancer.
For women ages 30 to 65, there are three options: a test for "high risk" strains of HPV every five years, a Pap test every three years, or co-testing with both the HPV and Pap test every five years. Women in this age group should speak with their doctor about which testing method is best for them, the guidelines say.
The guidelines do not apply to women who have symptoms of cervical cancer, regardless of their sexual history, the USPSTF says. Nor do they apply to women who have previously been diagnosed with cervical cancer or with a high-grade precancerous lesion, or to women who have a condition that weakens their immune system, such as HIV.
How are the guidelines different from before?
Although HPV tests have been used for years to help screen for cervical cancer, it's the first time that national guidelines have recommended the sole use of HPV tests for women ages 30 to 65.
The draft guidelines released in September 2017 originally did not include co-testing as a recommended screening method. However, some doctors expressed concern about the need for a transition period before HPV-only testing is adopted as a screening method for women ages 30 to 65, according to an editorial accompanying the study. In the final recommendations, co-testing was added back as a recommended method.
Why were the guidelines updated?
The updated guidelines are based on the findings of recent studies, including one by Melnikow and colleagues, that found that testing for high-risk strains of HPV detected a higher rate of precancerous lesions in the cervix, compared with Pap tests.
"Our work demonstrated that there is now strong evidence for the effectiveness of high-risk HPV testing used alone as a cervical cancer screening test," Melnikow said.
Both HPV testing alone and co-testing were also slightly more effective at reducing deaths from cervical cancer than Pap testing alone, according to a separate study, also published today in JAMA. That study, which used a model to simulate the effectiveness of different screening strategies over women's lifetimes, found that, without screening, about 830 in 100,000 women would die from cervical cancer in a given population. But if women were screened with HPV testing every five years beginning at age 30, the rate of death dropped to 29 per 100,000 women. If women were screened with co-testing beginning at age 30, the rate of death was similar — about 30 deaths per 100,000 women. And if women were screened with the Pap test alone, the rate of death was higher — about 76 deaths per 100,000 women.
Are there downsides to using the HPV test?
Both the HPV test alone and co-testing have higher rates of false positives (meaning the tests detect HPV or abnormal results when a woman does not have HPV, cancer or precancer) than the Pap test, with co-testing having the highest false-positive rate, according to the guidelines. But the USPSTF concluded that, in women ages 30 to 65, all of the recommending screening methods (HPV test alone, co-testing or Pap testing alone) "offer a reasonable balance between benefits and harms" of screening, the guidelines say.
What other effects could the guidelines have?
While a Pap test must be done in a doctor's office, HPV tests could potentially be done at home, meaning that women would collect a sample and mail it to a lab for analysis. Indeed, some small studies have suggested that "at home" HPV tests are a promising method of screening for high-risk HPV infections in women who don't visit the doctor for screening. Therefore, "self-collection may be one strategy for increasing screening rates," the guidelines say. However, more rigorous studies are needed to test this hypothesis and examine how such a method could be implemented, the guidelines say.
Further studies are also needed to examine whether HPV vaccinations, which reduce the risk of HPV infection, could affect how well HPV tests work in screening for cervical cancer.
Original article on Live Science.
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Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.