Association of p16 and Ki-67 with Risk of Recurrence in Previously Treated Cervical High-Grade Squamous Intraepithelial Lesions

Abstract

Objective: Our main objective was to assess the association between the markers p16 and Ki-67 and recurrence of disease in patients previously treated for cervical high-grade squamous intraepithelial lesion (HSIL).

Design: This is a case-control study at the National Cancer Institute conducted between 2005 and 2015. Of the patients with a pathologically confirmed diagnosis of HSIL, 107 cases were selected. They were divided into 2 groups: 28 cases with recurrence after treatment and a control group of 79 patients without recurrence. We identified clinical, pathological, and treatment variables.

Methods: Two experienced pathologists performed immunohistochemical analysis of biomarkers; they agreed on their interpretation, and we calculated the odds ratios (ORs) associated with recurrence. For group comparisons, we used the Wilcoxon signed-rank, χ2, or Fisher's exact test, depending on the type of variable. We conducted logistic regression models to estimate ORs and determine the factors associated with recurrence. The recurrence-free period was defined as the time frame between conization and either recurrence of disease or the last date the patient was seen. We used Kaplan-Meier plots to visualize survival curves and log-rank tests to compare the curves. We established a p value <0.05 as statistically significant.

Results: After pathologists performed immunohistochemical analysis, they achieved an agreement level of 83.7% for p16 and 60% for Ki-67. We did not find an association between recurrence and either p16 expression (p = 0.69) or the percentage of Ki-67 expression (p = 0.71). The recurrence-free period analysis did not reveal a difference in p16 expression (p = 0.57) nor in the percentage of Ki-67 expression in the 3-tiered scale (p = 0.56).

Limitations: Our main limitation was a reduced sample size.

Conclusion: We found no association between p16 and Ki-67 positivity and the risk of recurrence in previously treated HSIL.

Keywords: Cancer of cervix; High-grade squamous intraepithelial lesion; Human papilloma virus infection; Neoplasm recurrence; p16/Ki-67 immunostaining.