To the Editor We read with concern the article by Mohan et al.1 First, this is not a case-control study in which participants are sampled based on the presence (case) or absence (control) of a given disease. Instead this is a retrospective cohort study of patients exposed or not exposed to vismodegib.
In addition, non–basal cell carcinoma (BCC) secondary cancers were defined as being associated with vismodegib therapy if they were diagnosed at least 2 weeks after the first exposure to vismodegib. Is it possible to include events occurring so early after treatment?
Puig S, Sampogna F, Tejera-Vaquerizo A. Study on the Risk of Cutaneous Squamous Cell Carcinoma After Vismodegib Therapy for Basal Cell CarcinomaNot a Case-Control Study. JAMA Dermatol. 2016;152(10):1172-1173. doi:10.1001/jamadermatol.2016.2428