A study of treatment failures following large loop excision of the transformation zone for the treatment of cervical intraepithelial neoplasia

Objective To examine the long term efficacy of large loop excision of the transformation zone (LLETZ) in the treatment of cervical intraepithelial neoplasia (CIN) and to evaluate the relative diagnostic merits of colposcopy and cytology in the follow up of these women. Design A retrospective examination of cytology, colposcopy and histology records of the first 1000 women treated with LLETZ in Aberdeen from 1989 to 1991. Setting Colposcopy Clinic Aberdeen Royal Infirmary, Grampian Region, Scotland. Results Nine hundred and seventy-seven women (97.7%) were seen for follow up at least once and 317 were followed for as long as four years. This comprises 2812 woman years of follow up. The incidence of recurrent CIN was 27/1000 woman years and the cumulative rate of recurrence at four years was 10.1 per 100 women. Twenty-eight of the 59 women (47%) with abnormal colposcopy and proven CIN had a concurrent smear that did not show dyskaryosis. Conclusions LEETZ is an effective form of treatment for CIN. Colposcopy was useful in the follow up of these women and expedited the treatment of persistent disease. We recommend that any follow up protocol should include a colposcopic assessment and cytological follow up for at least four years following treatment. Further data are required to determine the risk of recurrence beyond this time.