Abstract

Spontaneous regression of cervical intraepithelial neoplasia grade 2 (CIN2) lesions has been recognized since 1955, but predictors of this are poorly understood. Among the predictive markers studied, p16^INK4a has been suggested to be of some value in monitoring the diagnosis of CIN2. In this clinical trial, 90 Brazilian women, diagnosed to CIN2 and high-risk human papillomavirus infection, were randomized into two groups of equal size: 45 women whose lesions were excised and 45 women subjected to prospective follow-up at 3-month intervals at least for 1 year (mean 6.8 months). p16^INK4a expression was analyzed in paraffin-embedded sections using immunohistochemical staining. Among the 45 women in the follow-up group, 42% experienced spontaneous regression, 11% showed persistence, 22% progressed to CIN3, and 20% had partial regression to CIN1 or ASCUS (atypical squamous cell undetermined signifiance). p16^INK4a expression was detected in 68.9% of the patients. In univariate survival (Cox) analysis, no significant difference in regression was obtained between p16^INK4a-negative and -positive CIN2 lesions (adjusted HR = 1.1; 95% CI 0.6–2.0). In conclusion, p16^INK4a expression could be useful in the diagnosis of CIN2. However, it failed to predict the outcome of CIN2. Because of its high spontaneous regression rate, follow-up could be considered as a management option of CIN2 in young and compliant women.