'Efficacy and safety of imiquimod 5% cream for basal cell carcinoma: a meta-analysis of randomized controlled trial': a critical appraisal

Aim Jia and He aimed 'to compare the efficacy and safety of imiquimod with other treatments in patients with basal cell carcinoma' (BCC). Design and inclusion criteria Meta-analysis of studies that included patients with histologically confirmed BCC treated with imiquimod 5% cream compared with all other treatments, including vehicle, excisional surgery, cryosurgery, fluorouracil and methyl aminolaevulinate photodynamic therapy. Outcomes The main outcome measures included histological and composite clearance rates, success rates, complete response rates, tumour-free survival and adverse events. Results Thirteen studies with a total of 4265 patients were included in the review. Pooled analyses comparing imiquimod with all or any of the listed comparators, including vehicle, demonstrated higher histological clearance rates [risk ratio (RR) 9 center dot 28, 95% confidence interval (CI) 5 center dot 56-15 center dot 5; P < 0 center dot 001], higher composite clearance rates (RR 34 center dot 2, 95% CI 21 center dot 3, 55 center dot 1; P = 0 center dot 001), no significant difference in success rates (RR 0 center dot 98, 95% CI 0 center dot 89-1 center dot 08; P = 0 center dot 73), higher complete response rates (RR 3 center dot 15, 95% CI 1 center dot 55-6 center dot 38; P = 0 center dot 001), no significant difference in tumour-free survival (RR 1 center dot 15, 95% CI 0 center dot 98-1 center dot 35; P = 0 center dot 088) and increased incidence of adverse events (RR 2 center dot 00, 95% CI 1 center dot 39-2 center dot 88; P < 0 center dot 001). Conclusions The authors state that 'imiquimod significantly exhibited benefit effect in improving the histological/composite clearance rates' compared with other treatments, and they suggest it could be used as the first-choice treatment for patients with BCC. Comment The main concerns related to the article by Jia and He are that the research question is replicative, it makes little sense to combine all BCC types in a meta-analysis, and it also makes no sense to combine an active treatment against a combination of vehicle and other active treatments. There are also concerns about bias related to the use of the same study data more than once in a meta-analysis. Furthermore, we have identified an example of covert duplicate publication, which further compounds the profusion of misleading systematic reviews.