Incidence of Basal Cell Carcinoma and Squamous Cell Carcinoma in Patients on Antiprogrammed Cell Death-1 Therapy for Metastatic Melanoma

Systemic melanoma therapies have the potential to affect basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cuSCC) development. In this study, we aim to compare the incidence of BCC and cuSCC in patients with metastatic melanoma treated with antiprogrammed cell death-1 (anti-PD1), BRAF inhibitor (BRAFi) monotherapy or dabrafenib and trametinib combination therapy (CombiDT) with a group of control patients having similar risk factors. We reviewed the records of melanoma patients on anti-PD1, BRAFi, or CombiDT, and patients from the High-Risk Melanoma Clinic, Westmead Hospital. We also performed an immunohistochemical analysis of BCCs under anti-PD1 compared with controls using PD1, PD-L1, CD3, CD8, and CD20 stains. For the results, in all, 340 patients were included; 82 on anti-PD1, 134 on BRAFi, 69 on CombiDT, and 55 controls. BRAFi had the highest incidence of BCC (12.7%), followed by CombiDT (10.1%) and anti-PD1 (2.4%). The incidence of BCC was significantly lower in patients on anti-PD1 (2.4% vs. 19.4%; P