Defining the Longitudinal Risk of CIN 3+ for <CIN 2 Colposcopy for Patients Referred With High-Grade Cytology

Abstract

Objective To determine the baseline and cumulative risk of cervical intraepithelial neoplasia (CIN)3 and invasive cervical cancer in participants referred to colposcopy with high-grade cytology and <CIN2 histology, stratified by biopsy result. Methods The authors linked administrative databases including cytology, pathology, cancer registries, and physician billing history to identify participants referred to colposcopy between January 2012 and December 2013 with high-grade cytology (atypical squamous cells [ASC]-H, high-grade squamous intraepithelial lesion [HSIL], invasive squamous cell carcinoma, adenocarcinoma, atypical glandular cells [AGC], adenocarcinoma in situ) and had <CIN2 (with and without biopsy confirmation) at colposcopy. Three- and 5-year risks of CIN3 and invasive cervical cancer were generated using Kaplan-Meier survival analysis. Results Among 4,168 women referred to colposcopy for ASC-H, HSIL, squamous cell carcinoma, or adenocarcinoma, the 3- and 5-year CIN3 incidence rates were 17.7%/20.0% no biopsy, 13.0%/15.1% negative biopsy, and 18.9%/20.0% low-grade squamous intraepithelial lesion (LSIL) biopsies. The 3- and 5-year incidences of invasive cancer were: 1.25%/1.68% no biopsy, 0.78%/1.04% negative biopsy, and 0%/0% LSIL biopsy. When the initial cytology was AGC/adenocarcinoma in situ (n = 944), the 3- and 5-year rates of CIN3 were 7.42%/8.39% no biopsy, 7.41%/9.26% negative biopsy, and 7.69%/7.69% LSIL biopsy. The invasive cancer rates were 1.12%/1.54% no biopsy, 0.46%/0.46% negative biopsy, and 0.0%/0.0% LSIL biopsy. By screening cytology, participants referred for HSIL had the highest 3- and 5-year rates of CIN3 (18.9% and 21%) compared with AGC (7.22%/8.28%) and ASC-H (15.5%/18%). The 3- and 5-year invasive cancer rates were 1.38%/1.75% HSIL, 0.85%/1.17% AGC, and 0.91%/1.36% ASC-H. Conclusions In participants referred for high-grade cytology where colposcopy shows <CIN2, the subsequent risk of invasive cancer at 5 years is sufficiently elevated to warrant close surveillance in colposcopy.