p16/Ki-67 dual stain, PAP cytology and HR-HPV test results prior to and 6 months after a LLETZ procedure: a prospective observational cohort study.

OBJECTIVES: To investigate the effect of a LLETZ procedure on p16/Ki-67 dual stain, PAP cytology and HR-HPV test results on cervical cytology samples obtained prior to and 6 months after the procedure. Secondary aims are to assess dependency between test results at the time of follow-up and explore dual stain positivity rates according to known risk factors for persistence/recurrence of cervical intra-epithelial neoplasia (CIN). STUDY DESIGN: Prospective observational cohort study conducted in the Department of Gynaecology at the University Hospitals of Leuven, Belgium. All patients referred for a LLETZ procedure were invited to participate. A cervical cytology sample was obtained just prior to and 6 months after the procedure. Every sample was used for PAP staining (cytology), p16/Ki-67 dual staining (dual stain test, DST) and HR-HPV genotyping. Test results were compared between both timepoints using the McNemar test. Dependency was assessed cross-sectionally at the time of follow-up using a chi-squared test. RESULTS: From the 110 participants originally included, 83 attended follow-up (75.5%). Mean duration of follow-up was 187.91 days (SD 21.47) and mean age was 41.4 years (SD 11.08). DST positivity rates were 70.9 and 30.1% prior to and 6 months after the procedure (p < 0.001). HR-HPV testing (positive or negative) and abnormal PAP cytology (evaluated at an ASCUS or worse threshold) showed a similar significant reduction in positivity rates (84.5 vs 42.2% and 72.7 vs 28.9%, respectively, p < 0.001). Results of all three assays showed high dependency at the time of follow-up (DST and PAP, PAP and HR-HPV test, DST and HR-HPV test-p values < 0.001). The highest proportion of positive DST results was seen in patients carrying HPV16 (84.6%), followed by any HR-HPV type (60%), those treated for CIN2 + (27.3%) and those with positive margins on the cone specimen (26.7%). CONCLUSION: A LLETZ procedure results in a significant decrease in abnormal DST, PAP cytology and HR-HPV test results in this diverse cohort of patients. The highest proportion of abnormal DST results was seen in patients carrying HR-HPV at the time of follow-up, especially HPV 16.

The use of p16/Ki-67 dual staining technology on cervical cytology of patients undergoing a LLETZ procedure.

OBJECTIVES: The main objective of this prospective observational study was to investigate the diagnostic performance of the p16/Ki-67 dual stain technique (DST) for detecting CIN 2+ in a LLETZ referral setting. Test performances were compared with HR-HPV testing and Pap cytology. METHODS: All patients referred for a LLETZ procedure were candidates for participation in this trial. A total of 110 patients were enrolled between October 2016 and March 2017. From each participant, a cervical cytology sample was obtained before the onset of the LLETZ procedure. On each sample, the dual stain technique (Roche CINtec PLUS ® test), Pap cytology and an HPV DNA assay (identifying 17 different HPV types) were performed. RESULTS: The overall disease prevalence of CIN 2+ was 56%. The mean age was 41 years, with 38% of patients being younger than 35 years. The overall sensitivity and specificity of the dual stain technique for detecting CIN 2+ was 94% (95% CI: 84.30-98.21%) and 58% (95% CI: 43.21-72.93%) respectively with a PPV of 74% (95% CI: 67.34-80.31%) and a NPV of 88% (95% CI: 72.48-94.90%). HR-HPV testing results in a similar sensitivity of 92% (95% CI: 82.17-97.33%) but considerable lower specificity of 21% (95% CI: 11.17-33.35%) compared to the dual stain technique. At an ASCUS or worse threshold, Pap cytology had the lowest sensitivity of 89% (95% CI 78.11-95.34%) compared to dual staining and HR-HPV testing. Specificity was better (48% with 95% CI of 33.29-62.81%) than that of HR-HPV testing but not as good as the DST. CONCLUSION: p16/Ki-67 dual staining provides high sensitivity and improved specificity compared to HR-HPV testing and Pap cytology for detecting CIN 2+, making it an interesting tool for identifying relevant disease in patients referred for a LLETZ procedure.