Needle versus loop diathermy excision of the transformation zone for the treatment of cervical intraepithelial neoplasia:: a randomised controlled trial

(CIN) may be achieved by needle excision of the transformation zone (NETZ) than with loop excision (LLETZ). Design A prospective randomised controlled trial. Setting A gynaecological oncology centre and a teaching hospital in West London. Population Four hundred and four women due to receive treatment for suspected CIN. Methods Women were randomised to receive either LLETZ or NETZ. Main outcome measures The study was designed to demonstrate a difference in the proportion of women with clear histological margins of 82% for LLETZ compared with 94% for NETZ with 90% power at a 5% significance level, allowing for absence of CIN in the treatment specimen in 15%. Results Four randomised women were excluded from the analysis, as they were ineligible for the study. Three hundred and forty-seven (87%) had CIN in the treatment specimen and could be included in the analysis of excision margins. More women in the NETZ arm had clear histological margins (84.8% vs 75%, P = 0.03). The median volume of specimens in the NETZ arm was 739 mm(3) larger (P = 0.33) and they were less likely to be removed in multiple pieces (2.5% vs 29.5%, RR 0.09, 95% Cl 0.04 to 0.20). Needle excision took longer to perform (median treatment time 210 vs 90 seconds, P <0.0001) and surgeons more often reported the procedure as 'difficult' (9.5% vs 3.0%, RR = 3.17, 95% Cl 1.33 to 7.58). No difference in perioperative or post-operative complication rates could be demonstrated between the two groups. Conclusion NETZ is more likely to produce a specimen in one piece and with clear margins compared to LLETZ.