Diagnosis and treatment of Basal cell and squamous cell carcinoma.

Family physicians are regularly faced with identifying, treating, and counseling patients with skin cancers. Nonmelanoma skin cancer, which encompasses basal cell and squamous cell carcinoma, is the most common cancer in the United States. Ultraviolet B exposure is a significant factor in the development of basal cell and squamous cell carcinoma. The use of tanning beds is associated with a 1.5-fold increase in the risk of basal cell carcinoma and a 2.5-fold increase in the risk of squamous cell carcinoma. Routine screening for skin cancer is controversial. The U.S. Preventive Services Task Force cites insufficient evidence to recommend for or against routine whole-body skin examination to screen for skin cancer. Basal cell carcinoma most commonly appears as a pearly white, dome-shaped papule with prominent telangiectatic surface vessels. Squamous cell carcinoma most commonly appears as a firm, smooth, or hyperkeratotic papule or plaque, often with central ulceration. Initial tissue sampling for diagnosis involves a shave technique if the lesion is raised, or a 2- to 4-mm punch biopsy of the most abnormal-appearing area of skin. Mohs micrographic surgery has the lowest recurrence rate among treatments, but is best considered for large, high-risk tumors. Smaller, lower-risk tumors may be treated with surgical excision, electrodesiccation and curettage, or cryotherapy. Topical imiquimod and fluorouracil are also potential, but less supported, treatments. Although there are no clear guidelines for follow-up after an index nonmelanoma skin cancer, monitoring for recurrence is prudent because the risk of subsequent skin cancer is 35 percent at three years and 50 percent at five years.