Review of high-risk features of cutaneous squamous cell carcinoma and discrepancies between the American Joint Committee on Cancer and NCCN Clinical Practice Guidelines In Oncology.

Cutaneous squamous cell carcinoma (SCC) is a malignancy that arises from epidermal keratinocytes. Although the majority of cutaneous SCC cases are easily treated without further complication, some behave more aggressively and carry a poor prognosis. These "high-risk" cutaneous SCCs commonly originate in the head and neck and have an increased tendency toward recurrence, local invasion, and distant metastasis. Factors for high-risk cutaneous SCC include large size (>2 cm), a deeply invasive lesion (>2 mm), incomplete excision, high-grade/desmoplastic lesions, perineural invasion (PNI), lymphovascular invasion, immunosuppression, and high-risk anatomic locations. Both the National Comprehensive Cancer Network® (NCCN® ) and the American Joint Committee on Cancer (AJCC) identify several of these high-risk features of cutaneous SCC. The purpose of this article was to review the high-risk features included in these guidelines, as well as their notable discrepancies and omissions. We also provide a brief overview of current prophylactic measures, surgical options, and adjuvant therapies for high-risk cutaneous SCC. © 2016 Wiley Periodicals, Inc. Head Neck 39: 578-594, 2017.