Benefits and potential harms of human papillomavirus (HPV)-based cervical cancer screening: A real-world comparison of HPV testing versus cytology

Introduction: Human papillomavirus (HPV) testing as the primary cervical cancer screening method is implemented in several countries. We report data from the first round of a large Danish pilot implementation of HPV-based screening. Our aim was to compare colposcopy referrals, detection of high-grade cervical intraepithelial neoplasia (CIN) and cervical cancer, and positive predictive value (PPV) of colposcopy referral in HPV vs cytology-based screening.

Material and methods: From May 2017 to October 2018, women aged 30-59 years attending cervical cancer screening in the uptake area of the Department of Pathology, Vejle Hospital, Region of Southern Denmark were screened by primary HPV testing (n = 16 067) or primary cytology (n = 23 981) depending on municipality of residence. In the HPV group, women with HPV16/18, or other high-risk HPV types and abnormal cytology, were referred to immediate colposcopy. Women with other high-risk HPV types and normal cytology were invited for repeat screening with HPV test and cytology after 12 months. From a nationwide pathology register, we obtained information on screening results and subsequent histological diagnoses during up to 2.9 years after the first screen. PPVs included diagnoses within 1 year after referral.

Results: In the HPV group, 3.7% were referred to immediate colposcopy and 2.8% were referred at the 12-month repeat screening. The total referral to colposcopy was higher in the HPV (6.6%) than cytology group (2.1%) (age-adjusted relative referral = 3.05, 95% confidence interval [CI] 2.75-3.38). The detection of CIN3+ was higher in the HPV (1.5%) than the cytology group (0.8%) (age-adjusted relative detection = 1.88, 95% CI 1.56-2.28). The probability of CIN3⁺ among women referred to colposcopy (= PPV) was lower in the HPV (21.1%; 95% CI 18.7%-23.7%) than the cytology group (34.6%; 95% CI 30.7%-38.9%). In the HPV group, the PPV was lower among women referred at repeat screening (12.1%) than among women referred immediately (27.8%).

Conclusions: Compared with cytology-based screening, HPV-based screening provided a 90% increased CIN3+ detection at the cost of a threefold increase in colposcopy referrals, when considering complete data from the prevalence round. Our findings support implementation of HPV-based screening in Denmark, but modifications of screening algorithms may be warranted to decrease unnecessary colposcopy referrals.