Use of antiepileptic drugs and risk of skin cancer: A nationwide case-control study

Background: Several antiepileptic drugs are photosensitizing; however, it is not known whether this confers an increased risk of skin cancer. Objective: To examine the association between common antiepileptic drugs and basal cell carcinoma, squamous cell carcinoma (SCC), and malignant melanoma. Methods: We conducted a nested case-control study identifying skin cancer patients in Denmark from 2004 through 2015 matched 1:10 with disease-free controls. We estimated odds ratios (ORs) for skin cancer associated with high cumulative use of antiepileptic drugs ($500 defined daily doses) compared with nonuse. Results: Most antiepileptic drugs were not associated with skin cancer. SCC was associated with use of carbamazepine (OR, 1.88; 95% confidence interval, 1.42-2.49) and lamotrigine (OR, 1.57; 95% confidence interval, 1.12-2.22) with evidence of a dose-response relationship for carbamazepine. The estimated absolute risks were low; for example, 6335 person-years of high cumulative exposure to carbamazepine were required for 1 additional SCC to occur. Limitations: Data on important risk factors for skin cancer, such as sun exposure, were not available. Conclusions: Most antiepileptic drugs were not associated with skin cancer; however, carbamazepine and lamotrigine were associated with SCC. These findings need to be replicated and characterized further in other settings and have no direct clinical implications.