Evaluation of p16(INK4a)/Ki-67 dual stain in comparison with an mRNA human papillomavirus test on liquid-based cytology samples with low-grade squamous intraepithelial lesion.

BACKGROUND: The objective of the current study was to investigate the clinical performance of detecting high-grade lesions with the CINtec PLUS p16(INK4a)/Ki-67 dual stain and the APTIMA human papillomavirus (HPV) Assay in a cohort of women with low-grade squamous intraepithelial lesion (LSIL) cytology. The authors also assessed the reproducibility of the evaluation of immunocytochemical staining.

METHODS: The 2 tests were performed on liquid-based residual material from 469 women with LSILs. The samples had at least 5 years of follow-up and the gold standard used was high-grade cervical intraepithelial neoplasia (CIN2+/CIN3+) proven on histology.

RESULTS: Approximately 69% of all the women included in the study had a positive test for HPV mRNA and 56% was positive for the dual stain. The 2 tests demonstrated high sensitivities. When examining the specificities, the APTIMA HPV Assay performed with significantly lower values than the CINtec PLUS test. For patients with CIN2+, the APTIMA HPV Assay had a specificity of 36.1% versus 51.3% for the CINtec PLUS test, and for women with CIN3+, the specificity was 33.8% versus 48.2%, respectively. The difference was even more pronounced when analyzing women aged < 30 years separately. The kappa values between the 3 observers in scoring the dual stain ranged from 0.43 to 0.49 and improved in a second evaluation round to values ranging from 0.50 to 0.66.

CONCLUSIONS: The CINtec PLUS p16(INK4a)/Ki-67 dual-staining test in LSIL cytology samples demonstrated high sensitivity that was similar to that of the APTIMA HPV Assay in the detection of underlying high-grade disease but with enhanced specificity, especially among women aged < 30 years. The kappa value for the evaluation of the CINtec PLUS dual-staining test was moderate but could be improved through training.