Comparative analysis of HPV testing versus cytology in Danish cervical cancer screening: Insights from a large-scale implementation study

Objective
Human papillomavirus (HPV) testing is the recommended primary screening method against cervical cancer. Denmark started implementing HPV testing as a primary screening method in 2021, but no national data are yet available. We report the results of the first and second screening rounds in a large Danish pilot implementation study. The objective was to compare colposcopy referrals, identify high-grade cervical intraepithelial neoplasia (CIN) and cancer, and positive predictive value (PPV) between HPV-based and cytology-based screening.
Method
In the HPV SCREEN DENMARK cohort (established May 2017–December 2019), participants were assigned to HPV-based (n = 28,677) or cytology-based screening (n = 43,622) based on the municipality of residence.
Results
The first round of screening showed higher colposcopy referrals in the HPV group (6.4 %) compared to cytology (2.3 %), with HPV screening detecting more CIN3+ (n = 306/28,677 (1.1 %)) than cytology (n = 241/43,622 (0.6 %)) (RR = 1.9 (95 %CI 1.6–2.3). In absolute terms, 41 additional colposcopy referrals resulted in the detection of 10 more cases of CIN2+ and five extra CIN3+ cases per 1000 women screened. The PPV for CIN3+ of a colposcopy initiated by routine screening was similar in the HPV group (24.1 %) and cytology group (25.7 %). Within the initial years of screening, the cumulative incidence of CIN3+ and cervical cancer showed a more rapid increase in the HPV group compared to the cytology group.
Conclusion
HPV-based cervical screening detects almost twice as many CIN3+ cases but at the expense of a more than two-fold increase in colposcopy referrals. Furthermore, we found that HPV-based screening detects cervical cancer earlier than cytology-based screening.