Screening and vaccination against HPV have reduced the incidence of cervical cancer, but researchers say some women are being screened for cervical caner too often — partly because of vaccination.
Last year, the CDC came out with a report showing that nearly three-quarters (71.5%) of adolescents between the ages of 13 and 17 had received at least one dose of the human papillomavirus (HPV) vaccine. Just over half (54.2%) had completed their vaccination series and were considered up-to-date.
Those rates are increasing each year, which is important because nearly 36,000 Americans are receiving diagnoses of cancer that are probably caused by HPV infection each year, according to the CDC. The most common type of cancer caused by HPV infections in women is cervical cancer.
The FDA first approved the HPV vaccine in 2006. Initially indicated for girls and young women, the vaccine is now available starting at age 9 for males and females, through age 45. HPV infection is extremely common among sexually active individuals, but the rising rates of HPV vaccination should, theoretically, lead to decreasing rates of certain types of cancer. New data appear to back that up, and screening also plays an important role. But for cervical cancer, screening has become a conundrum. On the one hand, it seems to be having a meaningful impact, lowering the incidence of cervical cancer and the deaths from the disease. On the other hand, evidence from studies seems to show that it is overused.
At the 2021 meeting of the American Society of Clinical Oncology, Cheng-I Liao, M.D., of Kaohsiung Veterans General Hospital in Taiwan, presented new data showing that cervical cancer rates decreased by an average of 1.03% per year in the U.S. from 2001 to 2017.
It’s not exactly clear why rates are dropping. Liao and colleagues used the United States Cancer Statistics database for their study, and those data sets do not include screening or vaccination. However, Liao told Managed Healthcare Executive® that there’s good reason to believe vaccination is a major driver of the declining rates. “(W)e found in the younger age group, especially in the age group 20 to 24, the cervical carcinoma age-specific incidence decreased more than other age groups,” Liao says. “We usually did not provide screening to this age group, (meaning) the major effect of the decrease was due to vaccination.”
The annual percentage change in the 20-to-24 age group was 4.63%, more than four times the percentage point decrease among those in the 30-to-34 age group. Those in the 20-to-24 age group in 2017 would have been between the ages of 9 and 13 in 2006, which would have put them in the first cohort of girls and young women for whom HPV vaccination was approved, Liao and colleagues noted in the abstract they presented at the ASCO meeting. Among patients ages 50 and older, rates are also dropping. Liao says that is likely because of screening, not vaccination, but HPV vaccination is not generally recommended for this age group.
Screening on the rise
Even as Liao’s report suggested that screening and vaccination were improving rates of cervical cancer, another report raised concerns about the overuse of screening. Writing in JAMA Network Open in April, Jason D. Wright, M.D., of the Columbia University College of Physicians and Surgeons, and his co-authors reported that women at average risk for cervical cancer were frequently overscreened for the disease. Using a database of 2.3 million commercially insured women, they found that nearly two-thirds (64.7%) of women between the ages of 30 and 65 who underwent cervical cancer screening in 2013 and 2014 were tested again within 36 months of their index test.
The American Cancer Society’s 2012 guidelines suggested cervical cancer screening every three years or cotesting with HPV and cytologic testing every five years for women in that age group. The association later updated those guidelines to call for HPV testing every five years. Wright and colleagues noted that the overuse of screening can lead to a variety of unnecessary procedures. “Identification of transient HPV infections and low-grade abnormal findings likely to resolve spontaneously often leads to further diagnostic testing with colposcopy and biopsies and, possibly, ablative or excisional procedures,” they wrote. “These procedures are often associated with psychological stress and physical symptoms.” Wright and colleagues also noted that treating preinvasive surgical lesions can have negative consequences on pregnancy, including preterm birth.
Overscreening also leads to significant costs for the healthcare system. A 2015 study modeled HPV screening scenarios found current screening practices, based on a database of patients in New Mexico, were inefficient and had a lower health benefit compared with guidelines-based screening. By following the screening guidelines perfectly, which at the time called for cytological testing every 3 years, physicians would save money and improve health outcomes.
Liao agrees that overscreening can be a problem, not only because it can lead to extra costs and extra patient management, but also because it is not always a good use of the providers’ time. But Liao adds that said overscreening is also a byproduct of improving rates of cervical cancer.
“When the prevalence and incidence are higher, the proportion of overtesting in screening is small,” he points out. “When the prevalence and the incidence are reduced by screening or vaccination, the proportion of overtesting in screening will increase. We should balance the cost and the benefit.” Wright and his co-authors said their research also sheds light on another problem: Many women have conflated cervical cancer screening with regular gynecological exams.
“In our study, we found that 74% of women who did not have extra cervical cancer screenings also did not have a gynecologic examination,” Wright wrote in an essay on Columbia University’s website. “I think in women’s minds, annual gynecological exams and cervical cancer screening tests are indelibly linked. But that doesn’t necessarily need to be the case.”
Role of guidelines
For Wright, one major problem is that neither patients nor physicians understand the best practices for screening. “As data on testing strategies evolve, guidelines change frequently and multiple ... professional societies release their own, different screening guidelines, patients and clinicians are often unaware of screening recommendations or may be confused by the lack of consensus among guidelines,” he and his colleagues wrote in JAMA Network Open.
Liao says it takes time for new recommendations to filter down to the clinic to the point where they are widely followed. In the meantime, he believes that researchers should keep close tabs on disease status and screening and vaccination rates to ensure that guidelines match the real-world situation. “We should … provide up-to-date suggestions or guidelines (and) continue to educate our health providers and people,” he says. “We can decrease the probability of overtesting and save lives and money.”
At the same time, Liao’s research also suggests that the status quo for cervical cancer, where guidelines exist and evolve even if they are not always followed, is better than the alternative. He and colleagues found that rates of other HPV-related cancers, including oropharyngeal, anal and rectal squamous cell carcinoma, are on the rise. Those cancers either cannot be screened for or there is a lack of clear screening guidelines, Liao says. Lori Pierce, M.D., ASCO’s president, said in a news release that the juxtaposition of cervical cancer rates falling while other HPV-related cancers are increasing points to a need for better screening guidelines. “Clearly, this study shows that we still have a great deal of work to do in order to reverse the increasing incidence rates of other HPV-related cancers,” she commented.
Jared Kaltwasser is a medical writer who lives in Iowa.