August 04, 2020
The American Cancer Society (ACS) has released updated guidelines for cervical cancer screening. The key recommendation is that primary human papillomavirus (HPV) testing is the preferred screening method, starting at the age of 25 and repeated every 5 years.
In the past, guidelines for cervical cancer screening recommended cytology (the Pap test) starting at 21 years of age and repeated every 3 years. In more recent years, cotesting (with both Pap and HPV tests) has been recommended.
Since the last ACS guidelines on cervical cancer screening were published in 2012, two HPV tests have been approved by the US Food and Drug Administration (FDA) for use in primary HPV screening.
The new "streamlined recommendations can improve compliance and reduce potential harms," commented Debbie Saslow, PhD, managing director, HPV/GYN Cancers, American Cancer Society.
The updated guidelines were published online July 30 in CA: A Cancer Journal for Clinicians.
"We now have stronger evidence to support starting cervical cancer screening at a later age and to recommend screening with the HPV test as the preferred test," Saslow told Medscape Medical News. This also reflects the phasing out of cytology and cotesting, she added.
"This update is based on decades of studies comparing the effectiveness of HPV testing to cytology and is bolstered by evidence of the impact of HPV vaccination, including a dramatic decline in cervical precancers and, more recently, cervical cancers among young women," she said.
The American Society for Colposcopy and Cervical Pathology (ASCCP) said that it was preparing a response to these new guidelines, as is the American College of Obstetricians and Gynecologists (ACOG).
Cotesting or Cytology Alone
The updated guidelines recommend primary HPV testing as the preferred screening method for all women with a cervix. If primary HPV testing is not available, women should be screened with cotesting, which should also be performed every 5 years.
If only cytology is available, then women should be screened every 3 years.
The ACS authors point out that cotesting or cytology testing alone is still an acceptable option for cervical cancer screening, insofar as primary HPV testing using FDA-approved tests may not be available in some settings.
As more laboratories in the United States transition to FDA-approved tests for primary HPV testing, it is expected that the use of cotesting or cytology alone will be phased out.
The new guidelines also emphasize that women may discontinue screening at the age of 65 if they have not had cervical intraepitheal neoplasia of grade 2 or higher within the past 25 years and if they have tested negative over the past 10 years on all past screens.
The authors caution that past screens should only be considered negative if the patient has had two consecutive negative HPV tests or two consecutive negative cotests or three consecutive negative cytology tests within the past 10 years.
"These criteria do not apply to individuals who are currently under surveillance for abnormal screening results," the authors state.
Women older than 65 for whom adequate documentation of prior screening is not available should continue to be screened until criteria for screening discontinuation are met, they add.
Screening may be discontinued among women with a limited life expectancy.
The authors note that HPV vaccination is expected to substantially change cervical cancer screening strategies.
In 2018, the National Immunization Survey–Teen, involving adolescents aged 13 to 17 years, showed that 68.1% of female patients were up to date on HPV vaccine recommendations, as were 51.1% of male patients.
"Cytology-based screening is much less efficient in vaccinated populations, as abnormal cytology disproportionately identifies minor abnormalities resulting from HPV types that are associated with lower cancer risk," the reports' authors point out.
As the prevalence of high-grade cervical abnormalities as well as the incidence of cervical cancer continue to decline, "the proportion of false-positive findings [on cytology alone] is expected to increase significantly," they caution.
As a result, the ACS suggests that physicians will likely have to consider a patient's vaccination status in tandem with cervical cancer screening results to arrive at an accurate assessment.
Raising Starting Age to 25 Years
Saslow also noted that there were several reasons why it is now recommended that screening begin at the age of 25 instead of the age of 21, as in earlier guidelines.
"Firstly, less than 1% of cervical cancers are diagnosed before the age of 25 — so this is about 130 cases per year," she explained.
Thanks to HPV vaccination, this percentage is further declining, "so screening is just not beneficial at this age," Saslow emphasized.
Furthermore, the rate of false positives is much higher in younger patients, and a false positive result can have a negative impact on pregnancy outcomes, she added.
Saslow also dismissed an article in favor of cotesting instead of HPV testing alone. That study, carried out by researchers at Quest Diagnostics and the University of Pittsburgh Medical Center, recommended cotesting, claiming that primary HPV testing is significantly less likely to detect cervical precancers or cervical cancer than cotesting.
"These data come from parties with a vested interest in preserving cytology as a screening test," Saslow told Medscape Medical News. She noted that "these findings are not at all credible as judged by the scientific community."
On the basis of their own modeling, ACS researchers estimate that "starting with primary HPV testing at age 25 will prevent 13% more cervical cancers and 7% more cervical cancer deaths" in comparison with cytology (Pap testing alone) beginning at the age of 21, then cotesting at the age of 30, Saslow said in a statement.
"Our model showed we could do that with a 9% increase in follow-up procedures but with 45% fewer tests required overall," she added.
The new recommendations are not expected to create any change in the type or amount of care required by providers, and patients will not notice any difference, inasmuch as cotesting and primary HPV testing are performed the same way in the examination room, she added.
"Resistance [to the changes] is expected — and is already occurring — from laboratories and manufacturers of tests that will no longer be used once we transition from cotesting and, less commonly, Pap testing to primary HPV testing," Saslow said.
However, providers need to be aware that HPV infection, as with any sexually transmitted disease, is associated with a certain stigma, and they need to take care in discussing potential HPV infection with their patients.
Medscape Medical News approached Mark Einstein, MD, president of the ASCCP and professor and chair of obstetrics, gynecology, and reproductive health at Rutgers Biomedical and Health Sciences, Newark, New Jersey, to comment on the new guidelines.
"First and foremost," he said, "everything we want to do when it comes to screening is to maximize the identification of picking up a cancer and minimize the risk or potential harm of not only screening itself but of missing cancers, so any strategy that improves on the sensitivity of picking up a cancer is a good method."
Nevertheless, inasmuch as the ASCCP is one of the foremost organizations involved in cervical cancer screening and management, its members need more time to take a closer look at the updated ACS guidelines before they, together with sister organizations, such as the ACOG, release an official statement as to whether or not they fully endorse the new guidelines.
The United States Preventive Services Task Force recently endorsed primary HPV testing (starting at age 30), but it also said that an alternative strategy is cotesting for women between 30 and 65 years of age, Einstein observed.
Asked to comment on the article from Quest Diagnostics and the University of Pittsburgh that recommended cotesting instead of primary HPV testing, Einstein said that that suggestion should not be dismissed out of hand.
The ASCCP has asked the authors of that study for their data in order conduct an independent assessment of it, largely because the study was retrospective in nature. Because of that, "there may have been a few pieces of information that were missing in true real-time fashion," he said. "Not having [both the primary HPV testing and the cytology results] in front of me might change the next thing I might recommend to the patient," Einstein explained.
The bottom line is that when comparing primary HPV testing alone, cytology alone, and cotesting and rates of cervical cancer at 5 years, "the biggest driver for true performance of positive predictive value is HPV," Einstein said.
Nevertheless, cotesting does bring more information into the equation compared with primary HPV testing alone, although it also increases the potential for harm, including the harm of overtesting and conducting needless colposcopies, he added.
That said, starting primary HPV testing at the age of 25 rather than the age of 30, as was previously recommended, is very likely to lead to detection of spurious HPV infections, because HPV infections are very common among women in their 20s, Einstein pointed out.
"This, too, could potentially lead to more colposcopies, which may cause harm from the procedure itself but also create a certain amount of anxiety and concern, so there is some harm in testing for HPV at an earlier age as well," Einstein said.
Saslow and Einstein have disclosed no relevant financial relationships.