The role of p16INK4a immunostaining in the risk assessment of women with LSIL cytology: a prospective pragmatic study

Background: The detection of high-grade cervical intraepithelial neoplasia (CIN2 or worse) among patients with low-grade cytology (LSIL) is challenging. The aim of this study was to assess the efficacy of p16(INK4a) in the risk assessment of women with LSIL cytology. Methods: Consecutive liquid-based cytology specimens of 95 LSIL smears were selected and stained for p16(INK4a). All patients had colposcopically directed punch biopsies or large loop excision of the transformation zone of the cervix. The endpoint was detection of a biopsy-confirmed CIN2 or worse. Results: The overall sensitivity and specificity of p16(INK4a) for diagnosis of CIN2+ among LSIL smears were 41% and 86%, respectively. The positive predictive value of the biomarker was 62% and the negative predictive value 72%. Conclusions: The study shows that p16(INK4a) has low sensitivity but acceptable specificity for evaluation of LSIL smears harbouring high-grade lesions. The marker needs to be further assessed as an adjunct to other tests in an attempt to improve the triage of LSIL cytology smears.