Japanese Dermatological Association guidelines: Outlines of Japanese clinical guidelines for basal cell carcinoma 2021.

To summarize the current therapies for skin cancers, the Japanese Skin Cancer Society issued the first guidelines for skin cancers, including melanoma, squamous cell carcinoma, basal cell carcinoma (BCC), and extramammary Paget's disease, in 2007. These guidelines were revised in 2015. Herein, we present the English version of the 2021 edition of the Japanese clinical guidelines for BCC. In the latest edition, all procedures were performed according to the Grading of Recommendations, Assessment, Development and Evaluation systems. The clinical questions that could not be answered were selected for further analysis. A comprehensive literature search, systematic review, and recommendations for each clinical question were determined by a multidisciplinary expert panel comprising dermatologists, a plastic and reconstructive surgeon, and a pathologist. Surgical resection is the gold-standard therapy of BCC. Radiotherapy or topical treatments, other than surgical resection, have been used in some cases. Patients with unresectable or metastatic BCC require systemic therapy. Novel agents, such as immune response modifiers or hedgehog pathway inhibitors, are emerging worldwide for the treatment of BCC. Based on these viewpoints, four relevant clinical questions regarding, surgical resection, radiotherapy, topical treatment, and systemic therapy, were raised in this report that aims to help clinicians select suitable therapies for their patients.