Although screening and follow-up rates were lower than expected in this trial, the option of testing for HPV at home may prove to be a game-changer.
Cervical cancer almost always can be prevented if women get screened for human papillomavirus (HPV). Unfortunately, too many women skip the recommended screenings, which is when cervical abnormalities typically are caught; half of all cervical cancers are found in women who have not been adequately screened for it. In an effort to determine whether barriers to screening such as difficulty finding time to schedule a clinic visit, transportation problems, inability to secure child care, or fear of being examined physically are behind the lack of screening, investigators mailed at-home HPV screening kits to a selection of women.
The investigators, from the University of Washington and Kaiser Permanente, both in Seattle, used electronic medical records to identify women between ages 30 and 64 years who had Kaiser Permanente health insurance for more than 3 years, had a primary healthcare provider, had not had a hysterectomy, and had no record of a recent Papanicolaou test (Pap smear). Nearly 20,000 women were enrolled in the study between February 2014 and August 2016. Half were randomly assigned to the standard of care study arm, which meant reminders to go to a clinic for screening, and half were assigned to the intervention arm, which entailed receiving screening reminders plus an at-home screening kit.
The primary outcomes of the study, which was published in JAMA Network Open, included detection of cervical precancer within 6 months of screening, and getting treatment for cervical precancer within 6 months of its detection.
Overall, the mailed test kits significantly increased the rate of HPV screening: 26% of women who received 1 either used it and returned it or saw their health care provider for in-office testing, while just 17% of women in the standard of care group got screened.
This initial screening resulted in 12 women in the intervention group who had abnormal results, which call for repeat testing or colposcopy—a procedure that involves closely examining the cervix, vagina and vulva for evidence of disease—compared with 8 women in the control arm. However, the number of cervical precancers diagnosed in the 2 groups was similar.
“When we designed the trial, we thought that the increase in screening with mailed HPV kits would be even higher than we observed,” Rachel L. Winer, PhD, a professor in the department of epidemiology at the University of Washington School of Public Health, and an author of the study, told Contagion®. “This is 1 reason why we think there was not a significant increase in detection of precancers in the intervention group versus the control group. Cervical precancers are not very common, so we would have needed a larger difference in screening between the 2 groups in order to see a statistically significant difference in the number of precancers detected.”
In an invited commentary on the study, faculty members in the department of obstetrics and gynecology at Johns Hopkins University noted that while home testing for HPV may play a greater role in cervical cancer screening going forward, the results of this study suggest that modifications are needed. “It is especially concerning that slightly less than half of patients (41%) who had positive test results for HPV-16 or HPV-18 (the HPV types most likely to lead to cervical cancer) did not adhere to the recommended colposcopy,” they wrote. “This percentage may have been further diminished by the 6-month limitation on measurement of follow-up for enrolled patients.”
Part of the problem, according to Winer, is the oft-changing clinical guidelines for cervical cancer screening, which in 2018 evolved to include HPV testing only—no Pap smear needed—every 5 years for women between 30 and 64. “Now that primary HPV screening (i.e., HPV only) is a guideline-approved screening strategy in the US, there is a real possibility for home-based HPV screening to become a widespread option for women,” she said. “This is because HPV tests—unlike Pap tests—can be performed on either a clinician-collected or self-collected sample with similar accuracy. I’m hopeful that home-based HPV screening will become a routinely available option in the future. Education for patients and providers will be important for encouraging women to self sample, follow up in the clinic when indicated, and trust the results.”