Litha Pepas, Sonali Kaushik, Andy Nordin, Andrew Bryant, Theresa A Lawrie

This is an updated version of a review first published in theCochrane Database of Systematic Reviews, Issue 4, in 2011. Vulval intraepithelial neoplasia (VIN) is a pre-cancerous condition of the vulval skin and its incidence is increasing in women under 50 years. High-grade VIN (also called usual-type VIN (uVIN) or VIN 2/3 or high-grade vulval intraepithelial lesion) is associated with human papilloma virus (HPV) infection and may progress to vulval cancer, therefore is usually actively managed. There is no consensus on the optimal management of high-grade VIN; and the high morbidity and relapse rates associated with surgical interventions make less invasive interventions highly desirable. To evaluate the effectiveness and safety of medical (non-surgical) interventions for high-grade VIN. We searched the Cochrane Gynaecological Cancer Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2015, Issue 3), MEDLINE and EMBASE (up to 30 March 2015). We also searched registers of clinical trials, abstracts of scientific meetings, reference lists of included studies and contacted experts in the field. Randomised controlled trials (RCTs) that assessed non-surgical interventions in women diagnosed with high-grade VIN. We used Cochrane methodology with two review authors independently abstracting data and assessing risk of bias. Where possible, we synthesised data in meta-analyses using random effects methods. Five trials involving 297 women with high-grade VIN (defined by trial investigators as VIN 2/3 or VIN 3 or 'high-grade' lesions) met our inclusion criteria: three trials assessed the effectiveness of topical imiquimod versus placebo; one assessed topical cidofovir versus topical imiquimod; and one assessed low- versus high-dose indole-3-carbinol in similar types of participants. Three trials were at a moderate to low risk of bias, two were at a potentially high risk of bias.Meta-analysis of the three trials comparing topical imiquimod 5% cream to placebo found that women in the active treatment group were more likely to show an overall response (complete and partial response) to treatment at five to six months compared with the placebo group (Risk Ratio (RR) 11.95, 95% confidence interval (CI) 3.21 to 44.51; participants = 104; studies = 3; I(2) = 0%; high-quality evidence). A complete response at five to six months occurred in 36/62 (58%) and 0/42 (0%) participants in the active and placebo groups, respectively (RR 14.40, 95% CI 2.97 to 69.80; participants = 104; studies = 3; I(2) = 0%). A single trial reported 12-month follow-up, which revealed a sustained effect in overall response in favour of the active treatment arm at 12 months (RR 9.10, 95% CI 2.38 to 34.77; moderate-quality evidence), with 9/24 (38%) and 0/23 (0%) complete responses recorded in the active and placebo groups respectively. Progression to vulval cancer was also documented in this trial (one versus two participants in the active and placebo groups, respectively) and we assessed this evidence as low-quality. Only one trial reported adverse events, including erythema, erosion, pain and pruritis at the site of the lesion, which were more common in the imiquimod group. Dose reductions occurred more frequently in the active treatment group compared with the placebo group (19/47 versus 1/36 participants; RR 7.77, 95% CI 1.61 to 37.36; participants = 83; studies = 2; I(2) = 0%; high-quality evidence). Only one trial reported quality of life (QoL) and there were no significant differences between the imiquimod and placebo groups.For the imiquimod versus cidofovir trial, 180 women contributed data. The overall response at six months was similar for the imiquimod and cidofovir treatment groups with 52/91 (57%) versus 55/89 (62%) participants responding, respectively (RR 0.92, 95% CI 0.73 to 1.18). A complete response occurred in 41 women in each group (45% and 46%, respectively; RR 1.00, 95% CI 0.73 to 1.37). Although not statistically different, total adverse events were slightly more common in the imiquimod group of this trial with slightly more discontinuations occurring in this group. Longer term response data from this trial are expected.The small trial comparing two doses of indole-3-carbinol contributed limited data. We identified five ongoing randomised trials of various interventions for VIN. Topical imiquimod appears to be a safe and effective treatment for high-grade VIN (uVIN), even though local side-effects may necessitate dose reductions. However, longer term follow-up data are needed to corroborate the limited evidence that response to treatment is sustained, and to assess any effect on progression to vulval cancer. Available evidence suggests that topical cidofovir may be a good alternative to imiquimod; however, more evidence is needed, particularly regarding the relative effectiveness on longer term response and progression. We await the longer-term response data and the results of the five ongoing trials.