Large loop excision of the transformation zone (LLETZ) compared to carbon dioxide laser in the treatment of CIN: a superior mode of treatment. A series of 199 patients with histologically confirmed cervical intraepithelial neoplasia (CIN) grade II or III were allocated by hospital number to receive out-patient treatment by carbon dioxide laser vaporization or large loop excision of the transformation zone (LLETZ). All patients received local anaesthesia. The women in the LLETZ group experienced less post operative haemorrhage, less discomfort, operative time was greatly reduced, and histological material was available for confirmation of the diagnosis. There was no significant difference in recurrence of CIN after treatment between the two groups. At 6 month follow-up, recurrence rates of 8.2% (CIN II) and 7.5% (CIN III) were observed in the laser-group and 5% (CIN II) and 5.3% (CIN III) in the LLETZ group. Further advantages of LLETZ are reduced capital expenditure and no hazard to the eyesight of the surgeon, but laser treatment is preferable in patients with widespread vaginal involvement. 