Comparison between Colposcopically Directed Biopsy and Large Loop Excision of the Transformation Zone

Abstract

Objective Firstly to assess the accuracy of colposcopically directed biopsy in comparison with
final diagnosis, secondly to assess correlation and agreement between colposcopically
directed biopsy (CDB) and large loop excision of the transformation zone (LLETZ)
Setting Department of Obstetrics and Gynaecology, Faculty of Medicine, Ramathibodi Hospital.
Study design Retrospective study.
Material and Method A comparative analysis was conducted from the 234 women referred to
colposcopy clinic at Ramathibodi Hospital from January 1998 to December 2006, to compare
between CDB and LLETZ. Accuracy was assessed by the percentage of concordance
between CDB and final diagnosis. The correlation and the agreement were assessed by
Spearman’s rank correlation coefficient (r) and Kappa statistics (K).
Results A 89.74 % accuracy was found between CDB and final diagnosis. The correlation
and the agreement between CDB and LLETZ were low (r = 0.30, p < 0.0001; K = 0.26, p <
0.0001). The CDB had overcall and undercall rates of 19.31% and 9.87%, respectively.
Conclusion Even though the correlation and agreement between CDB and LLETZ were rather
low, but the accuracy was quite high. So, in our setting CDB is still of clinical use.