Risk of subsequent cutaneous malignancy in patients with prior keratinocyte carcinoma: a systematic review and meta-analysis.

In this systematic review and meta-analysis the risk of a subsequent basal cell carcinoma (BCC), squamous cell carcinoma (SCC) or melanoma in patients with a previous keratinocyte carcinoma (KC) was investigated. PubMed, Embase, Web of Science and the Cochrane library were searched for studies published before 1st January 2012 that reported risks (i.e. proportions, cumulative risks or standardised incidence ratios [SIR]) of developing a subsequent BCC, SCC or melanoma in patients with prior KC. 45 articles fulfilled the inclusion criteria. In BCC patients, the pooled proportion for a subsequent BCC, SCC or melanoma was respectively 29.2% (95% confidence interval (CI) 24.6-34.3%), 4.3% (1.7-10.1%) and 0.5% (0.4-0.8%). The pooled proportion of a subsequent SCC, BCC or melanoma in SCC patients was respectively 13.3% (95% CI 7.4-22.8%), 15.9% (5.6-37.6%) and 0.5% (0.3-0.6%). The pooled SIRs for a subsequent BCC, SCC or melanoma were respectively 17.4 (95% CI 0.0-37.4), 3.2 (0.0-6.5) and 2.4 (2.3-2.6) in BCC and 4.2 (95% CI 2.0-6.5), 15.0 (14.0-16.0) and 2.7 (2.3-3.2) in SCC patients. In the subgroup analyses, strongest differences in risks were found in the continent strata (risks Australia>North America>Europe).