Assessment of Colposcopy Accuracy as Predictors of High-Grade Histology Outcomes in Large Loop Excision of the Transformation Zone: 12 Months Retrospective Analysis
Giulia Gremmo*, Bidisha Chatterjee, Pedra Rabiee and Krishnanayan Haldar
ABSTRACT
Introduction: This study evaluated the diagnostic accuracy of colposcopic assessment and the effectiveness of large loop excision of the transformation zone (LLETZ) in the management of cervical intraepithelial neoplasia (CIN) within a tertiary UK centre.
Methodology: A retrospective review was conducted of 284 consecutive women who underwent colposcopy and LLETZ at Addenbrooke’s Hospital, Cambridge, between 1 January and 31 December 2023. Primary outcomes included adequacy of excision depth, histological margin status, and Test-of-Cure (TOC) outcomes. Depth adequacy was defined according to transformation zone (TZ) type (TZ1 ≥7 mm, TZ2 ≥10 mm, TZ3 ≥15 mm). Demographic and clinical characteristics were recorded.
Results: Of the 284 LLETZ procedures, 87.7% were performed as a single excisional specimen, meeting national quality standards. TOC success was achieved in 89% of cases. The positive predictive value of colposcopy for detecting high-grade histology was 82.5% among women referred with high grade cytology and 69% overall. Adequate excision depth was achieved in 59% of cases, with the highest adequacy observed in Type 1 transformation zones (64%). Complete excision with negative margins was achieved in 61.4% of cases, with lower rates observed in Type 2 and Type 3 transformation zones. Margin positivity was more frequent among younger women aged 25–34 years.
Conclusion: Colposcopy and LLETZ demonstrated high diagnostic accuracy and effective disease clearance in this tertiary centre. While overall outcomes aligned with national standards, achieving adequate excision depth and negative margins-particularly in Type 3 transformation zones-remains challenging. A cautious, individualised surgical approach may help balance oncological safety with fertility preservation while maintaining high TOC success.
