Squamous cell carcinoma is the second most common cancer of the skin. More than 250,000 new squamous cell carcinomas are diagnosed every year in the United States. Middle-aged and elderly people, especially those with fair complexions and frequent sun exposure, are most likely to be affected.
The cancer develops in the outer layer of the skin (the epithelium). Some squamous cell carcinomas arise from small sandpaper-like lesions called solar (sun) or actinic keratosis. It is possible for squamous cell carcinoma to spread to other areas of the body; therefore, early treatment is important.
Squamous cell carcinomas usually appear as crusted or scaly patches on the skin with a red, inflamed base, a growing tumor, or a non-healing ulcer. They are generally found in sun-exposed areas like the face, neck, arms, scalp, backs of the hands, and ears. The cancer also can occur on the lips, inside the mouth, on the genitalia, or anywhere on the body. Any lesion, especially those that do not heal, grow, bleed, or change in appearance, should be evaluated by a dermatologist.
Ultraviolet light exposure (from the sun or indoor tanning devices) greatly increases the chance of developing skin cancer. Although anyone can get squamous cell carcinoma, people with light skin who sunburn easily are at the highest risk. The chance of developing skin cancer increases with age and a history of severe sunburns as a child. Many less common skin conditions, organ transplantation, chronic skin ulcers, prior x-ray treatment (e.g., for acne in the 1950s), arsenic ingestion, smoking, and toxic exposure to tars and oils can predispose individuals to the development of squamous cell carcinoma.
These skin cancers are usually locally destructive. If left untreated, squamous cell carcinoma can destroy much of the tissue surrounding the tumor and may result in the loss of a nose or ear, for example. Aggressive types of squamous cell carcinomas, especially those on the lips and ears, or untreated cancers, can spread to the lymph nodes and other organs resulting in approximately 2,500 deaths each year in the United States.
A skin biopsy for microscopic examination may be done to confirm the diagnosis. A variety of different treatment options can be used depending on the location of the tumor, size, microscopic characteristics, health of the patient, and other factors. Most therapies are relatively minor office-based procedures that require only local anesthesia. Surgical excision to remove the entire cancer is the most commonly used treatment. "Mohs" micrographic controlled surgery, a method which requires specialized training by dermatologic surgeons, can be used to remove the tumor while sparing as much normal skin as possible. Other dermatologic surgical procedures include laser surgery, cryosurgery (liquid nitrogen - the frozen method), radiation therapy, and electrodesiccation and curettage which involves alternately scraping and cauterizing (burning) the tumor with low levels of electricity.