What Is It?
Squamous cells are small, flat skin cells normally found in the outermost layer of skin, called the epidermis. When squamous cells become cancerous (malignant), they typically develop into nodular or flat skin tumors, sometimes with a surrounding area of inflammation.
Most cases of squamous cell carcinoma are caused by unprotected, long-term exposure to the sun's ultraviolet rays. They usually occur on the sun-exposed skin of people who have spent a great deal of time outdoors, especially those with fair complexions and blue eyes. Occasionally, cancer develops within a scaly patch of sun-damaged skin called an actinic keratosis, which has a white, pink, yellow or brownish tint.
Although most cases of squamous cell carcinoma are related to sun exposure, a smaller number develop in skin that has been injured or exposed to carcinogens (cancer-causing agents). Common locations for this type of squamous cell cancer include:
Most squamous cell carcinomas that are detected early cause only a localized area of skin damage, usually on a sun-exposed portion of the head or hand. Depending upon the location, however, there can be disfiguring scarring if these skin cancers are not caught early and excised while they are small. In a small percentage of cases, the cancer is more aggressive and spreads (metastasizes) to the lymph nodes and other parts of the body. Squamous cell carcinoma is most likely to spread when it is on the lips, ears, penis, scrotum or vulva.
Squamous cell carcinoma is the second most common skin cancer in the United States, with more than 200,000 cases each year. Since the early 1980s, the number of cases has risen dramatically, increasing at a rate of about 10% per year. People with weakened immune defenses are at especially high risk of developing squamous cell cancer. This includes people who are HIV positive, have received transplants or are taking immune-suppressing medications.
Symptoms
Squamous cell skin carcinoma usually appears as a tiny, painless nodule or patch that sometimes, but not always, is surrounded by an area of inflammation. The surface of the cancer can be scaly, crusted or wartlike, and its center can form an open sore.
Although squamous cell carcinoma can develop on almost any part of the body, including the genitals and the soles of the feet, the most common locations are the head (scalp, lips, ears, inside the mouth), legs, or the back of the hands or on the arms.
Diagnosis
Your doctor will examine your skin and may shave away (excise) a small piece of abnormal skin to be examined in a laboratory. This procedure is called a biopsy. Occasionally, the doctor will remove the entire abnormal area and send it to a laboratory to be examined under a microscope.
In the laboratory, a pathologist will examine the biopsy specimen and determine if the specimen is a skin cancer. If so, the pathologist will examine the margins (borders) of the specimen to determine if the skin cancer has been removed by the biopsy. If any cancer cells remain at the margin, another procedure will be necessary to remove any remaining skin cancer cells.
Expected Duration
Once squamous cell carcinoma develops on the skin, it usually grows slowly. In general, if a squamous cell carcinoma is neglected and allowed to reach a diameter of more than 2 centimeters (about three-quarters of an inch), it is three times more likely to spread than a smaller cancer.
Prevention
Because squamous cell carcinoma is caused by unprotected exposure to sunlight, you can take several steps to help to prevent this cancer:
If you are taking prescription medications, and you spend significant time outdoors, ask your doctor if you need to take precautions to avoid sun exposure. Also, be aware that certain nonprescription skin-care products contain chemicals called alpha-hydroxy acids that can make your skin more vulnerable to damage from sunlight.
If a squamous cell carcinoma develops on your skin, you can limit the area of damage by detecting the problem early. To do this, examine your entire skin surface thoroughly every one to two months. Use a mirror to check for skin abnormalities on less visible areas of your back, shoulders, upper arms, buttocks and the soles of your feet.
Treatment
There are many surgical and nonsurgical ways to treat squamous cell carcinoma that has not spread. These include:
Which treatment is best for you depends on many factors, including the size and location of the cancer, whether it has returned after previous treatment, your age and your general health. Once your treatment is finished and your cancer is gone, your doctor will schedule follow-up skin examinations for you at regular intervals, such as every three months for the first year, and then less often after that.
When To Call a Professional
Call your primary care doctor or a dermatologist (a doctor who specializes in skin problems) if you notice that you have an abnormal nodule or patch anywhere on your skin, or if you have a skin ulcer that does not heal.
Prognosis
In most cases, the outlook is excellent. Overall, 95% to 98% of squamous cell carcinomas can be cured if they are treated early and have not spread. Once a squamous cell carcinoma has spread, the 5-year survival rate is less than 50%, even with aggressive cancer therapy.
Additional Info
National Cancer Institute (NCI)
U.S. National Institutes of Health
Public Inquiries Office
6116 Executive Blvd.
Room 3036A
Bethesda, MD 20892-8322
Phone: 301-435-3848
Toll-Free: 1-800-422-6237
TTY: 1-800-332-8615
Email: cancergovstaff@mail.nih.gov
http://www.nci.nih.gov/
American Cancer Society (ACS)
Toll-Free: 1-800-227-2345
TTY: 1-866-228-4327
http://www.cancer.org/
American Academy of Dermatology
P.O. Box 4014
Schaumburg, IL 60168-4014
Phone: 847-240-1280
Toll-Free: 1-888-462-7546
Fax: 847-240-1859
http://www.aad.org/
The Skin Cancer Foundation
149 Madison Ave.
Suite 901
New York, NY 10016
Phone: 212-725-5176
Email: info@skincancer.org
http://www.skincancer.org/
