Revised Mohs surgery care guidelines for squamous cell carcinoma in-situ are overdue

The treatment of cutaneous squamous cell carcinoma in situ by Mohs micrographic surgery is currently deemed as appropriate by the Mohs Appropriate Use Criteria. However, squamous cell carcinoma in situ is a very superficial, indolent, low-risk tumor amenable to destructive and non-surgical treatments. It is uncommon for squamous cell carcinoma in situ to have progressed to invasive malignancy subsequent to definitive management. The suggestion that squamous cell carcinoma in situ on certain anatomic locations has a poorer prognosis is widely assumed but lacks an evidence base. We recommend that most primary squamous cell carcinoma in situ in non-immunosuppressed patients be scored inappropriate or uncertain for Mohs micrographic surgery by the Mohs Appropriate Use Criteria. Multiple other efficacious treatment options exist for managing squamous cell carcinoma in situ, including curettage and cryotherapy, curettage and electrodessication, and topical therapies.