About 16% of skin cancers are squamous cell carcinomas. Chronic exposure to sunlight is the cause of most cases of squamous cell carcinoma. That is why tumors appear most frequently on sun-exposed parts of the body: the face, neck, bald scalp, hands, shoulders, arms, and back. The rim of the ear and the lower lip are especially vulnerable to the development of these cancers.
Although squamous cell carcinomas usually remain confined to the skin, they tend to be more aggressive than basal cell carcinoma. They will eventually penetrate the underlying tissues if not treated. In a small percentage of cases, they spread (metastasize) to distant tissues and organs. When this happens, they can be fatal. For these reasons, squamous cell carcinomas must be treated aggressively.
Squamous cell carcinomas can appear as wart-like growths that crust and bleed. They can also develop as persistent red patches or thick rough bumps. Any sore that oozes and bleeds is suspicious. Sores on the lips, including small ulcers, could also be skin cancer.
When a physician suspects squamous cell carcinoma, a skin biopsy will be performed to confirm the diagnosis. After confirmation, the treatment is similar to that for basal cell carcinoma. The treatment will vary based on location and tumor subtype. Aggressive tumors, recurrent tumors, or tumors on cosmetically important locations like the nose, lip, or ear are usually surgically removed with a specialized technique called Mohs surgery. Tumors in other locations can often be treated with standard surgical removal.
Following treatment, yearly follow-up is necessary for people who have had squamous cell carcinoma because, just like basal cell carcinoma, one-third of patients will develop a new tumor within three to five years.