Methods	RCT
Participants	Women who fulfilled criteria for cervical treatment for CIN and had not been treated previously. This included a cytological or colposcopic suspicion of CIN I or worse and unsatisfactory colposcopic examination in the presence of moderate or severe dyskaryosis or persistent mild dyskaryosis. Women with adenocarcinoma in situ were not included in the study Mean age in the trial was 32.6 years (SD=9.4 years) There were 149 (37.25%) women with CIN 1, 124 (31%) with CIN 2, 66 (16.5%) with CIN3, in 33 (8.25%) women there was no pretreatment histology and was another category in 28 (7%) women
Interventions	LLETZ: performed using a 1.5, 1.8 or 2.2 cm tungsten diathermy loop (Rocket, Watford, UK) according to the surgeon’s preference for a specific lesion. During a LLETZ procedure, surgeons used diathermy settings according to their usual practice Needle excision: performed with a 2 cm long tungsten wire (Rocket) using a pure coagulation setting of 35W. The intention with both techniques was to remove the specimen in one piece if possible
Outcomes	Duration of procedure Peri-operative pain Peri-operative complications Cervical stenosis
Notes	There was no difference in the cumulative risk of developing a recurrent or residual high grade intraepithelial lesion between the two groups at follow up (log-rank test= 0.13, P= 0.72) but the study would have needed over 1200 subjects to assess recurrence rates reliably Duration of procedure (secs): median= 90 [range: 60-120] for LLETZ procedure and median= 210 (range: 180-300) for NETZ
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Yes	“Women were randomised by telephone to the trial office where a computer generated randomisation list was kept securely. Block randomisation was used with varying sized groups”.
Allocation concealment?	Yes	“Women were randomised by telephone to the trial office where a computer generated randomisation list was kept securely”
Blinding? All outcomes	Unclear	“Histological analysis was performed by the routine pathological service in each hospital. Histopathologists were unaware of the type of treatment patients received”. However, it was unclear whether or not those analysing the data were blinded to the treatment mode
Incomplete outcome data addressed? All outcomes	Yes	For cervical stenosis outcome % of women analysed: 339/400 (85%) By treatment arm LLETZ: 167/200 (84%) Needle excision: 172/200 (86%) All other outcomes analysed at least 85% of women
Free of selective reporting?	Unclear	Insufficient information to permit judgement
Free of other bias?	Unclear	Insufficient information to assess whether an important risk of bias exists