Objectives: To determine the rate of cervical intraepithelial neoplasia grade 2 (CIN2+) in women with low grade cervical cytology and a normal colposcopy examination over 3 years of follow-up.
Design: Cohort study within a randomised controlled trial.
Setting: NHS Cervical Screening Programmes in Grampian, Tayside and Nottingham.
Population: Eight hundred and eighty-four women aged 20-59 years with borderline nuclear abnormalities (BNA) or mild dyskaryosis with a normal and adequate colposcopy examination.
Methods: Samples at baseline were tested for 14 high-risk (Hr) types using GP5+6+ methodology and for HPV 16 and 18 using type-specific primers. Women were followed up post-colposcopy by cervical cytology at 6-month intervals in primary care. After 3 years, women were invited for an exit colposcopy examination and underwent LLETZ if any colposcopic abnormality was identified.
Main outcome measures: Absolute and relative risks of CIN2+ during follow-up and/or at exit colposcopy.
Results: The median age was 36 years. The absolute risk of developing CIN2+ within 3 years was 1.86 per 100 woman years and for CIN3+, 0.64 per 100 woman years. One microinvasive cancer was identified. The relative risk (RR) was highest for women with initial mild dyskaryosis who were HrHPV-positive (RR 5.86, 95% confidence interval 2.53-13.56) compared with women with BNA who were HrHPV-negative.
Conclusion: For women with low grade cervical cytology, the risk of a high grade CIN within 3 years of a normal colposcopy examination is low. Women can be reassured that, even with a positive HPV test, the risk of developing CIN2 or worse is sufficiently low to return to the routine 3-year recall.
Keywords: Cervical intraepithelial neoplasia grade 2; colposcopy; human papillomavirus; low grade abnormalities.
© 2014 Royal College of Obstetricians and Gynaecologists.