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.