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SQUAMOUS CELL CARCINOMA
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Cutaneous squamous cell carcinoma (cSCC) is a keratinocyte-derived malignancy that is the second most common type of skin cancer. The therapeutic approach to SCC is guided by tumor classification. Tumors limited to the epidermis are classified as in-situ (Bowen’s disease), whereas those that involve the dermis and underlying structures are classified as invasive SCCs. Invasive SCCs can be further subclassified into low-risk and high-risk tumors based on clinical and histopathologic features. High-risk features include patient factors such as immunosuppression, while tumor features include tumor size (>2 cm), anatomic site, depth of histologic penetration of tumor (>6 mm or beyond subcutaneous fat), and degree of differentiation (poor). High-risk cSCCs can progress to become deeply invasive and locally destructive tumors that may no longer be amenable to surgical intervention, and such tumors are classified as locally advanced (laSCC). Approximately 2% to 5% of invasive SCCs (5-year risk) can also metastasize (metSCC) either regionally or distally resulting in significant morbidity and mortality. The primary goal of treatment is complete tumor clearance with preservation of surrounding function and cosmesis. In selecting a treatment modality, factors such as recurrence rate, patient comorbidities and preferences, and risk of adverse events must be considered. See Table 103-1.
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