Histological differences between colposcopic-directed biopsy and loop excision of the transformation zone (LETZ): a cause for concern.

Colposcopic examination and biopsy were performed on 100 patients with abnormal cervical cytology. All were suitable for ablative therapy but were treated by loop excision of the transformation zone (LETZ) as outpatients. Histological comparison between the colposcopic biopsies and LETZ samples showed poor agreement with only 43% of cases illustrating identical degrees of dysplasia. The dysplasia was underestimated by colposcopic biopsy in 16% of cases and overestimated in 41% of cases, when compared to the LETZ specimen. Microinvasive carcinoma was diagnosed in 3 cases on the LETZ histology, having been missed by the preceding colposcopy and colposcopic biopsy. The disparity between histological findings is of great concern and would not have been detected if the patients were treated by ablative therapy. It is the authors' view that LETZ should replace ablative therapy in the treatment of localized cervical dysplasia and that it may avoid the need for pretreatment colposcopic biopsy. LETZ limits the possibility of inadequate treatment and also provides a method of audit for the colposcopist.