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

Abstract

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) 9·28, 95% confidence interval (CI) 5·56-15·5; P < 0·001], higher composite clearance rates (RR 34·2, 95% CI 21·3, 55·1; P = 0·001), no significant difference in success rates (RR 0·98, 95% CI 0·89-1·08; P = 0·73), higher complete response rates (RR 3·15, 95% CI 1·55-6·38; P = 0·001), no significant difference in tumour-free survival (RR 1·15, 95% CI 0·98-1·35; P = 0·088) and increased incidence of adverse events (RR 2·00, 95% CI 1·39-2·88; P < 0·001).

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.