Cutaneous squamous cell carcinoma (SCC) is the second most common skin cancer in whites. Despite the fact that these tumors are largely preventable, the incidence of SCC is rising every year, and shows no signs of abating. While ultraviolet radiation is the most common cause of this type of cancer, other factors including ionizing radiation, human papillomavirus, chemical agents, immunosuppression, and chronically injured or inflamed skin also predispose to SCC development. Invasive SCC may arise from a precursor lesion such as actinic keratosis, or from SCC in situ, and may exhibit a wide spectrum of clinical features. Similarly, the histopathology of SCC may be viewed as a spectrum of squamous intraepithelial neoplasia, within which a variety of common and more unusual variants have been identified. Since invasive SCC has the potential to recur and metastasize, it is important to recognize those factors placing individual lesions at a higher risk for recurrence or metastasis. These include size >2 cm, location on the ear, lip, and other specific sites on the head and neck, as well as acral and genital regions, degree of histologic differentiation, perineural invasion, immunosuppression, and history of previous treatment. Treatment of primary cutaneous SCC is essential both to mitigate locally destructive growth and to minimize the risk of metastatic spread. While low risk lesions may be treated effectively with electrodesiccation and curettage, excision, cryosurgery, radiation therapy, or photodynamic therapy, high risk SCCs may require Mohs micrographic surgery or excision with wider margins to minimize their risk of recurrence. Adjunctive treatment with radiotherapy, lymph node dissection, systemic chemotherapy or biologic response modifiers may be required for the treatment of regional or distant metastatic disease. Screening via total body skin examination is the only test available to detect cutaneous SCC. Patients at risk for developing SCC should be identified early, and patients with a previous history of skin cancer should be monitored for the development of new and recurrent skin lesions. The role of prevention through sun avoidance and protection from sunlight, beginning in childhood, cannot be underestimated. Physicians should emphasize to their patients that these prophylactic measures will help to minimize their risk of developing this potentially life-threatening cancer, and that prompt detection of early disease will maximize their chance of complete treatment with a high rate of cure.
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