Squamous cell carcinoma (SCC) is the second most common skin cancer with between 200,000 and 250,000 cases reported each year. It is a malignant cancer that usually develops from the epidermis and/or the mucous lining of the body cavities (epithelium), but may occur anywhere on the body. SCC most often affects individuals who are exposed to large amounts of sunlight. Susceptibility is related to the amount of melanin pigment in the skin, and light-skinned persons are most vulnerable. With appropriate treatment, it is usually curable.
Squamous cell carcinoma may develop anywhere on the skin or mucous membranes. It is characterized by a red papule or plaque with a scaly or crusted surface. Most cases appear on sun-exposed areas of the body, but some occur in other areas such as the mouth. In some cases, the bulk of the lesion may lie below the skin, eventually ulcerating and invading the underlying tissue. It is estimated that in about two-thirds of the cases of lesions on the tongue or mucous membranes of the body, the disorder has not spread before it was diagnosed.
SCC is suspected whenever a small, firm reddish-colored skin lesion or growth or bump appears on the skin. It may also be a flat growth with a curly and crusted surface. Most often these growths are located on the face, ears, neck, hands and/or arms, but such SCC growths may occur on the lips, mouth, tongue, genitalia or other area.
Clinicians have concluded that extensive sun damage to the skin may cause “precancerous conditions”. Some of these include actinic keratosis, leukoplakia and Bowen’s disease. Actinic (sometimes called solar) keratoses consist of rough, scaly growths that range in color from brown to red. These growths may grow as large as one-inch in diameter and are more frequently found in older people. When actinic keratosis affects the lips (usually the lower lip), it is known as actinic cheilitis. Leukoplakia arises most often as white patches on the tongue or in the mucous membrane of the mouth. It is usually caused by smoking or by the persistent irritation of the gums because of ill-fitting dentures.
For more on Bowen’s disease, see Related Disorders, below.
The most common causes of squamous cell carcinoma are radiation from the sun and arsenic exposure. Skin that has been damaged by exposure to certain chemicals (carcinogens), heat, radiation, chronic skin ulcers or chronic draining sinuses is also susceptible to SCC. It may develop on normal tissue or it may develop on preexisting patches of precancerous tissue (leukoplakia).
Squamous cell carcinoma is a common form of skin cancer that affects men and women equally. Individuals who are chronically exposed to sunlight or arsenic are at higher risk of being affected. The Bowen’s disease form of this disorder affects both males and females. However, women are more apt to be affected when the disease is found in the genital area.
Treatment of squamous cell carcinoma depends upon the size, site and potential aggressiveness of the lesion. Methods of treatment include:
Curettage and desiccation is an in-office procedure that uses a special spoon-like instrument (curette) to scoop out the cancerous cells and tissue. This is followed by the application of an electric current to kill the remaining cells (desiccation). Surgical excision is a method of cutting out of the tumor and stitching up of the remaining tissue. Radiation therapy is used if the skin cancer is located in an area difficult to treat surgically. Microscopically controlled excision (Mohs surgery) involves the repeated cutting out of small pieces of tissue that is then examined microscopically. Repeated application of this technique minimizes the removal of healthy tissue and is cosmetically more satisfying, especially if carried out with a plastic surgeon as part of the medical team. The outlook for small squamous cell lesions that are removed early and completely is excellent.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government website.
For information about clinical trials being conducted at the National Institutes of Health (NIH) in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
nformation on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
For information about clinical trials sponsored by private sources, contact:
There is a tremendous amount of clinical trial activity on squamous cell carcinoma, with more than 100 studies listed (2005) on www.clinicaltrials.gov. Many of the investigational treatments involve chemotherapies, combinations of drugs, and drug comparisons to treat squamous cell carcinoma in its various stages and locations on the human body.
Two drugs have earned orphan status for treating squamous cell carcinoma. Intradose was designated an orphan drug in 2000 and is produced by Matrix Pharmaceuticals. Proxinium was designated an orphan drug in 2005 and is produced by a Canadian pharmaceutical company, Viventia Biotech, Inc.
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