Correlation between colposcopic and histological diagnosis of loop diathermy excised cervical lesions

Abstract

One hundred and eight patients treated by diathermy loop excision for cervical intra-epithelial neoplasia (CIN) were studied. Of the 103 patients who had punch biopsy, colposcopic examination underdiagnosed the severity of the cervical lesion as diagnosed by punch biopsy in 13.6 per cent. A total of 565 strips of cervical tissue were removed from 108 patients having loop diathermy excision; 75.4 per cent of the strips showed the same colposcopic and histological diagnosis. Colposcopic examination without biopsy underdiagnosed 10.7 per cent of the strips examined histologically, and 7.1 per cent of strips with histological abnormality had had a normal colposcopic appearance on examination. In 13.9 per cent of strips colposcopic diagnosis was more advanced than that found on histology, this could be due to overdiagnosis or the removal of the worst area by the punch biopsy which preceded the diathermy excision. Of 103 patients, 5.8 per cent had more advanced lesions on loop diathermy excision than on punch biopsy, indicating failure to biopsy the worst area under colposcopic guidance. There was only one micro-invasive carcinoma that had been treated with loop diathermy excision without prior punch biopsy.