Basal and Squamous Cell Skin Cancer Excision

Basal cell and squamous cell carcinomas are the two most common skin cancers, and most are caused by ultraviolet light from the sun or tanning beds. Basal cell carcinoma starts in the bottom (basal) layer of the epidermis, makes up about 80% of skin cancers, grows slowly and rarely spreads. Squamous cell carcinoma starts in the flat cells of the upper epidermis and makes up about 20%. It usually appears on the face, ears, neck, lips and backs of the hands, and can also start in scars or long-standing sores. It is more aggressive than basal cell cancer and can grow deeper and spread to other parts of the body. What sets this case apart from removing a benign skin lesion is that the specimen is a cancer, so the pathologist checks that the edges of the removed skin (the margins) are free of disease, by frozen section or by permanent sections. The operation itself is the same for both cancers: an ellipse of skin around the lesion, lined up with the skin tension lines, then direct closure, or a skin graft or flap when the defect is too large. Mohs surgery is a separate technique for these same cancers: thin layers are removed and checked under the microscope one at a time while the patient waits, until no cancer is left. Melanoma is treated more aggressively and may include sentinel node mapping, so it is not covered by this setup. These cases are usually done as same-day or outpatient surgery. A simple excision needs only a minor tray, a skin marker and an ESU, and is usually done with local anesthetic containing epinephrine; moderate sedation or general anesthesia may be added.