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

Abstract

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.