Clinical and Economic Value of p16INK4a for the Differential Diagnosis of Morphologic Cervical Intraepithelial Neoplasia 2.

ABSTRACT

The detection of high-grade intraepithelial lesions requires highly sensitive and specific methods that allow more accurate diagnoses. This contributes to a proper management of preneoplastic lesions, thus avoiding overtreatment. The purpose of this study was to analyze the value of immunostaining for p16 in the morphologic assessment of cervical intraepithelial neoplasia 2 lesions, to help differentiate between low-grade (p16-negative) and high-grade (p16-positive) squamous intraepithelial lesions. The direct medical cost of the treatment of cervical intraepithelial neoplasia 2 morphologic lesions was estimated. A retrospective observational cross-sectional study was carried out. This study analyzed 46 patients treated with excisional procedures because of cervical intraepithelial neoplasia 2 lesions, using loop electrosurgical excision procedures. Immunostaining for the biomarker was performed. For the estimation of overtreatment, percentages (%) and their 95% confidence interval were calculated. Of the 41 patients analyzed, 32 (78%) showed overexpression of p16 and 9 (22%) were negative (95% confidence interval, 11%-38%). Mean follow-up was 2.9 years, using cervical cytology testing (Pap) and colposcopy. High-risk human papillomavirus DNA tests were performed in 83% of patients. These retrospective results reveal the need for larger biopsy samples, which would allow a more accurate prediction of lesion risk. Considering the cost of p16 staining, and assuming the proper management of the low-grade lesion, an average of US$919 could be saved for each patient with a p16-negative result, which represents a global direct cost reduction of 10%.