Exogenous hormone therapy and non-melanoma skin cancer (keratinocyte carcinoma) risk in women: a systematic review and meta-analysis.

Previous studies reported inconsistent results regarding the association between keratinocyte carcinoma (KC) and exogenous hormone therapy. This study aimed to investigate the association between the use of exogenous sex hormones and the risk of KC among women. The databases of PubMed, Ovid Medline, Cochrane, and Web of Science were searched until May 2023. A total of 5293 patients with KC and 106,424 controls were included for analysis. The meta-analysis indicated that oral contraceptives (OC) and hormonal replacement therapy (HRT) use were associated with an increased risk of squamous cell carcinoma (SCC) (OR/RR = 1.25, 95% CI 1.10 to 1.43, I = 41.6%, p = 0.080). Subgroup analysis showed that OC use increased the risk of SCC (OR/RR = 1.37, 95% CI 1.15 to 1.63), whereas no significant association was shown between HRT use and risk of SCC (OR/RR = 1.13, 95% CI 0.93 to 1.37). Additionally, OC and HRT use were linked to an increased risk of basal cell carcinoma (BCC) (OR/RR = 1.16, 95% CI 1.09 to 1.25, I = 30.1%, p = 0.188). Further subgroup analysis suggested both OC and HRT use were associated with an increased risk of BCC (OC: OR/RR = 1.13, 95% CI 1.01 to 1.25; HRT: OR/RR = 1.19, 95% CI 1.09 to 1.30). In conclusion, our findings support the hypothesis that the risk of KC among women may be affected by the use of exogenous hormones.