Performance of P16 INK4a immunocytochemical stain in facilitating cytology interpretation of HSIL for women aged 50 and above

Abstract

Background Few articles have focused on cytological misinterpretation of the high-grade squamous intraepithelial lesion (HSIL) in older women. Due to estrogen deficiency, cervical epithelial cells in postmenopausal women tend to show atrophic change that looks like HISL, resulting in a higher rate of cytological misinterpretation. P16INK4a immunocytochemical staining (P16-cytology) can effectively differentiate diseased cells from normal atrophic ones with less dependence on cell morphology. Objective To evaluate the performance of P16-cytology in differential analysis of cytology high-grade squamous intraepithelial lesions and benign atrophy in women aged 50 years and above. Methods Included in this analysis were the women who were positive of hr-HPV in a cervical cancer screening project in central China and returned back for triage, with complete data of primary hr-HPV test, Liquid-based cytology, P16 immuno-stained cytology, and ptholosgy diagnosis. Included patients were divided into ≥ 50 (1,127 cases) and < 50 years (1,430 cases) of age groups. The accuracy of LBC in the diagnosis of ≥ HSIL was compared between the two groups, and detailed analysis was conducted to demonstrate how many cases with cytology ≥ HISL and pathology ≤ LSIL were P16 negative. Results The accuracy rate of LBC for detection of pathology ≥ HSIL was 86.9% (93/107) in age group of ≥ 50, significantly lower than that of 95.5% (105/110) in age group of < 50 years (P = 0.026). P16 immunocytochemical stains on cases with cytology ≥ HISL and pathology ≤ LSIL were all negative in both groups. Conclusion The misinterpretation of LBC- ≥HSIL was rated higher in older women. P16 immunocytochemical stain works well in differentiating atrophic changes from LBC- ≥HSIL.