The Prevalence of High Grade Cervical Intraepithelial Neoplasia (CIN) in a Primary Human Papillomavirus (HPV) Cervical Screening Programme Population with HPV Positive and Cytology Negative Smear Results

High-risk HPV is found in 99.7% of cervical cancers. The causative role of HPV in cervical cancer has led to the inclusion of HPV testing as part of cervical screening. A pilot of HPV testing as primary screening was commenced in 2013 at six pilot sites in England. North Cumbria Integrated Care (NCIC) NHS Foundation Trust took part in the pilot, in which women with an HPV-positive/cytology-negative result were recalled at 12 months. Women with HPV type 16/18 found at initial screening and persisting at 12 months in spite of negative cytology were referred to Colposcopy services at 12 months. Women with smear positive for hrHPV other than 16/18 types were recalled twice at 12 and 24 months before referral to colposcopy. Persistent hrHPV positive/cytology negative smear at 12 and 24 months initiated a colposcopy referral. Objective: To assess the prevalence of high grade CIN and invasive cancer in patients referred to colposcopy services at NCIC NHS Foundation Trust with hrHPV positive/cytology negative smears. Method: The study was conducted at NCIC NHS Foundation Trust between January 2015 and December 2017. Data was collected retrospectively from the colposcopy data base (INFOFLEX). All patients with HPV positive/cytology negative smears seen in colposcopy clinic during the study period were included. Patients with high grade CIN, cervical glandular intraepithelial neoplasia (CGIN) or invasive cancer were recorded. Results: 763 women were included in the study. A total of 50 (6.6%) women had high grade CIN, CGIN or invasive cancer. 40 of these 50 women (80%) were treated by large loop excision of the transformation zone (LLETZ). Conclusion: HPV primary screening is more effective than cytology-based screening. A high grade HPV positive result with negative cytology, persisting for one year in type 16/18 and for two years in other high-risk HPV types, warrants referral for colposcopy, as 6.6% of women in this study had high grade or invasive pathology.