CAP TODAY Pathology/Laboratory Medicine/Laboratory Management
Diane Davis Davey, MD
May 2019—In the November-December 2018 issue of the Journal of the American Society of Cytopathology is a fascinating analysis of human papillomavirus screening policies in Australia by researchers from New Zealand, a rebuttal by members of an Australian Cervical Cancer Screening Guidelines Working Party, and a thoughtful editorial by cervical cancer screening experts from the United States and England.
A new Australian cervical cancer screening policy replaced two-year cytology screening with five-year HPV screening and does not allow for cytology and HPV co-testing. The change of policy was based on modeling studies predicting a significant long-term decline in cervical cancer by this new screening policy. The analysis of this HPV screening policy by Cox and Sneyd predicts a 121 percent (95 percent confidence interval: 73 percent–169 percent) increase in annual incidence of cervical cancer compared with current incidence after 10 years. An additional 222 women are predicted to develop cervical cancer each year starting 10 years after the adoption of this new policy.
The authors discuss various biases introduced by modeling studies that look predominantly at the sensitivity of each test to detect high-grade cervical intraepithelial lesions (CIN). They argue that the Australian simulation model appears to be dependent on an assumption that high-grade CIN detection sensitivity by HPV and cytology also represents each test’s screening sensitivity. They define cancer screening sensitivity as the probability of detecting that subgroup of high-grade abnormalities that will progress to invasive cancer. The authors discuss concerns about overdiagnosis of precursors detected by HPV testing, many of which will regress, and suggest a more cautious approach to screening policy changes.