Squamous Cell Carcinoma

Skin cancer is a proliferation of abnormal cell growth in the skin. Squamous cell carcinoma (SCC) is the second most common type of skin cancer (after basal cell carcinoma). Squamous cell cancer is an abnormal growth in the squamous cells, the outermost layer of the epidermis.

Ultraviolet Light Exposure and Squamous Cell Carcinoma

Most cases of squamous cell carcinoma are related to the cumulative effects of sun exposure. The sun’s ultraviolet (UV) rays can penetrate the skin, damaging the DNA of genes that affect skin cells. In the case of squamous cell carcinoma, the p53 gene seems to be affected. The p53 gene is a tumor suppressor gene, which acts to prevent the growth and proliferation of abnormal cells. Once it is damaged, cancerous cells can grow and form tumors.

UV exposure can come both from the sun and from artificial indoor tanning beds or lamps. Individuals with occupations or hobbies leading to extensive UV exposure are at higher risk for developing SCC. A history of sunburns can also raise risk levels. Fair coloring, including light skin, eyes and hair, can make you more susceptible to the effects of UV radiation, therefore increasing susceptibility to squamous cell carcinoma. SCC is most likely to appear in individuals over 70 years of age, and appears more frequently in men than in women. In addition, it is the most common type of skin cancer in African-Americans.

You can help prevent squamous cell carcinoma by reducing sun exposure, particularly between 10 a.m. and 4 p.m., the hours when the sun is at its strongest. You can also take measures to protect your skin from the sun, using:

  • Hats
  • Protective clothing
  • Sunscreen
  • Umbrellas or sunshades.

Other Risk Factors for Squamous Cell Cancer

Other conditions can contribute to the development of a squamous cell carcinoma lesion. Individuals who have had a basal cell carcinoma lesion are more likely to develop SCC. Prior skin injury, including scars and exposure to chemicals (such as coal tar or arsenic) or radiation, may also contribute to an increased risk. Finally, a suppressed immune system, secondary to disease or medications taken after organ transplantation, can make you more susceptible to skin cancer, particularly squamous cell carcinoma.

Precancerous Skin Lesions

Squamous cell carcinoma may develop from certain precancerous skin lesions. The following conditions can be precursors to SCC:

  • Actinic cheilitis is a form of actinic keratosis affecting the skin on the lower lip.
  • Actinic keratosis is a rough and scaly patch of skin, red to brown in color, which develops as a result of prolonged sun exposure.
  • Bowen’s disease is an early phase of SCC (also called squamous cell carcinoma in situ). It presents with rough or scaly patches of skin that may resemble eczema. Bowen’s disease can be a result of exposure to sun, chemicals or carcinogens.

Squamous Cell Carcinoma Symptoms

Lesions can vary in appearance, but squamous cell skin cancer symptoms usually include rough, scaly sores, which bleed periodically or refuse to heal. Lesions may be flat to the skin, or elevated. Elevated lesions may have a raised edge and a depressed center, or they may resemble warts. Lesions can vary in color, including white, red or brown. Though it can appear on any part of the body, squamous cell carcinoma is most likely to appear on areas of skin frequently exposed to the sun, such as:

  • Back
  • Ears
  • Face
  • Forearms
  • Hands
  • Neck.

Early detection is important for effective squamous cell carcinoma treatment. Thus, the Skin Cancer Foundation and the American Cancer Society recommend annual skin examinations by a doctor, as well as self-examinations, to recognize any changes or new growths. Diagnosis can be confirmed when your doctor takes a sample of the lesion and examines it for cancerous cells, a procedure called a biopsy.

Treatment for Squamous Cell Carcinoma

Squamous cell carcinoma lesions and associated precancerous skin conditions are highly treatable when found early. However, undetected, they can grow deeper into the skin, making removal more invasive. In rare cases, they can even spread to lymph nodes or distant organs.

SCC can be treated with a variety of topical and surgical treatments. Mohs micrographic surgery removes affected skin one layer at a time, and is usually the least invasive surgical procedure. In other cases, simple excision of the lesion may be appropriate. Treatment varies on a case-by-case basis, and can also include techniques such as:

  • Cryosurgery
  • Electrodessication and curettage
  • Radiation therapy
  • Topical therapy.

More advanced cases, particularly those that have spread to lymph nodes or other organs, may require more advanced treatment, such as chemotherapy. As with other skin cancers, early detection of squamous cell carcinoma is important for successful treatment. Watch for changes in your skin, and report any new or abnormal growths to your doctor.

Resources

American Academy of Dermatology. (2010). Squamous cell carcinoma. Retrieved June 20, 2010, from http://www.aad.org/public/publications/pamphlets/sun_squamous.html

Mayo Clinic. (2009) Squamous cell carcinoma. Retrieved June 20, 2010, from http://www.mayoclinic.com/health/squamous-cell-carcinoma/ds00924

Medline Plus. (2009). Squamous cell carcinoma. Retrieved June 20, 2010, from http://www.nlm.nih.gov/medlineplus/ency/article/000829.htm

The Skin Cancer Foundation. (2010). Squamous cell carcinoma: the second most common skin cancer. Retrieved June 20, 2010, from http://www.skincancer.org/squamous-cell-carcinoma.html