Objective: To determine if semi-quantitative human papillomavirus (HPV) types 16 and 18 detection by polymerase chain reaction can increase the sensitivity and specificity of repeat cytology alone for underlying high grade cervical intraepithelial neoplasia (CIN).
Design: Prospective randomised study of immediate treatment and surveillance.
Setting: A dedicated colposcopy clinic serving a regional population.
Sample: Three hundred and four women with smears reported as mild dyskaryosis.
Methods: Repeat cytology, HPV 16 and 18 tests, and colposcopy were performed at study entry. Women were randomised to either immediate treatment or surveillance with repeated tests at 6 and 12 months. Unless all study smears were negative, women were treated at study exit by large loop excision of the transformation zone.
Main outcome measures: Sensitivity and specificity of HPV testing for types 16 and 18 in conjunction with cytology for high grade CIN.
Results: Combining repeat cytology with HPV 16 and 18 testing had a sensitivity of 94% and a specificity of 26%, a positive predictive value of 71%, and a negative predictive value of 71%, for underlying high grade CIN. If used to secondary screen in conjunction with repeat cytology for mild dyskaryosis, 88% of women would have been referred for colposcopy on the basis of either test being positive.
Conclusion: Combining repeat cytology and HPV 16 and 18 detection would result in the majority of women being referred for immediate colposcopy. Taken with an overall default rate of 17%, immediate referral of all women with mild dyskaryosis for colposcopic assessment still appears to be a more effective clinical strategy.