Effectiveness of self-collected HPV screening tests

A modeled analysis concluded that women who are underscreened for human papilloma virus (HPV) still benefit from self-administered tests, despite a loss in test sensitivity.

Widely collecting self-administered HPV tests, even with lower test sensitivity, can help in the fight against cervical cancer, according to a study published in Cancer Epidemiology, Biomarkers, and Prevention.

Megan A Smith, MPH, PhD, a senior research fellow in the cancer research division of the Cancer Council in New South Wales, Australia, and an honorary senior research fellow at the Sydney School of Public Health at the University of Sydney, along with collaborating authors, used a proven model to compare the impact of self-collected cervical screening samples on cancer diagnoses and deaths over a woman’s lifespan.

Study co-author Megan Smith, MPH, PhD

They included women with and without Australia’s restriction to women over age 30, and those 2 or more years overdue for HPV screening.

The results were compared with regular clinician-collected HPV screenings from women age 25 and older who were tested every 5 years. “We conservatively assumed sensitivity of HPV testing on self-collected relative to clinician-collected samples was 0.98. Outcomes were estimated either in the context of HPV vaccination … or the absence of HPV vaccination,” the authors wrote.¹

For unvaccinated women, the 2% worst-case loss of test sensitivity was outweighed by the health benefits, even if only 15% of women who would not ordinarily be screened used the test.

In regularly vaccinated women, “population-wide self-collection could be marginally (0.2-1.0%) less effective at 15% additional uptake, but 6.2-12.4% more effective at 50% additional uptake. Most (56.6-65.0%) of the loss in effectiveness in the restricted self-collection pathway in Australia results from the requirement to be 2 or more years overdue.”¹

Smith told Contemporary OBGYN® that researchers already know that most women prefer to collect their own samples.

“Some countries are now offering self-collection as an option to women who are overdue for cervical screening, but not to all women,” she said. Offering screenings in a restricted way, Smith said, prevents the process from achieving its full potential because it is too complicated for providers to know if women are eligible, and it is not widely promoted.

Following this study, Smith said that next steps were to inform women and providers about the tests’ safety and accuracy. “Clinical management pathways need to be reviewed, and ideally there would be a triage test that could be done on the same self-collected sample for women who test positive for HPV,” Smith said.

“Currently, cytology triage is used, so women still need to return for a speculum exam and clinician-collected sample.” Labs need time to prepare to process the self-collected samples, and systems that could automate the pre-analytic phase of processing would be very useful, Smith added.

“This study provides reassurance that self-collection could be offered more widely as an equal choice for women. This change would center screening around women’s preferences, making it more accessible for all.”

She emphasized that self-collection is faster, does not require health facilities, and would allow screening to continue in the context of disruptions like COVID-19. “One reason it was offered in a restricted way was that, previously, it was thought that self-collection was not as good as testing on a clinician-collected sample. We now know that’s not the case.”

“Reaching these women is critical to reduce cervical cancer rates,” Smith said, “and we have also shown in earlier work that it is the fastest way to eliminate cervical cancer.”

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Reference

1. Smith MA, Hall MT, Saville M, et al. Could HPV testing on self-collected samples be routinely used in an organised cervical screening program? A modelled analysis. Published online ahead of print November 20, 2020. Cancer Epidemiol Biomarkers Prev. 2020. doi:10.1158/1055-9965.EPI-20-0998. Accessed 6 December 2020.