Definition

Squamous cell carcinoma is a form of skin cancer. It is the second most common form of skin cancer.

The cancer develops in the uppermost layer of skin cells. Squamous cell carcinoma usually grows slowly. It is rarely fatal if treated early. However, the cancer can be lethal if it spreads beyond the skin.

Causes

Cancer occurs when cells in the body divide without control or order. Eventually these uncontrolled cells form a growth or tumor. The growths invade and take over nearby tissue. It is not clear exactly what causes these problems in the cells but it is probably a combination of genetics and the environment.

Risk Factors

Areas of skin that are damaged have a higher risk of cancer. Skin that is regularly exposed to the sun is most likely to develop skin cancer. Squamous cell carcinoma may also develop in skin that has scars, burns, or exposure to chemicals or radiation.

Factors that increase your risk of developing squamous cell carcinoma include:

• History of radiation or ultraviolet light treatment
• Childhood sunburns, freckling, or long periods of sun exposure
• A personal history of skin cancer
• A family history of skin cancer
• Blonde or red hair
• Blue or green eyes
• Fair skin that rarely tans
• Treatment that suppresses the immune system, such as such as having an organ transplant
• Frequent use of tanning beds
• Exposure to cancer causing chemical such as arsenic, tar, or some insecticides
• Being a smoker
• Past infection with human papillomavirus (HPV)

Symptoms

Symptoms include:

• A raised red patch that is scaly or rough
• A raised patch of skin that may appear to have horn-like rough edges
• In color, the patch may be reddish, pink, flesh-colored, or reddish-brown
• A long-standing sore that will not heal with simple at-home treatment

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done.

The skin growth will be examined. A sample of the growth will be taken and examined for cancer cells. This will help determine the stage and type of the cancer. The information will be used to guide treatment and make a prognosis.

Treatment

Talk with your doctor about the best treatment plan for you. Options include:

• Mohs micrographic surgery—microscopic surgery that offers the best cure rate for squamous cell carcinoma
• Removing the growth with simple surgery
• Plastic surgery to repair any cosmetic problems that occur after treatment

For people who are not able to have surgery, other treatment options include:

• Freezing the growth off with liquid nitrogen
• Laser treatment
• Radiation therapy
• Photodynamic therapy in which the cells absorb an acid that causes them to die when exposed to light
• Creams, especially fluorouracil or imiquimod

Prevention

To reduce your chances of getting squamous cell carcinoma, take these steps:

• Avoid spending too much time in the sun.
• Avoid exposing your skin to the sun between 10:00 AM and 2:00 PM standard time, or 11:00 AM to 3:00 PM daylight saving time.
• Protect your skin from the sun with clothing. Wear a shirt, sunglasses, and a hat with a broad brim.
• Use broad-spectrum (UVA and UVB) sunscreens with a sun protection factor (SPF) of 30 or more on skin that will be exposed to the sun.
• Use a protective lip balm.
• Wear sunglasses with 99% to 100% UV absorption to protect your eyes.
• Don’t use sun lamps or tanning booths.
• Get regular full-body skin exams by a dermatologist. The doctor will check for moles, freckles, and other growths.

American College of Mohs Micrographic Surgery http://www.mohscollege.org

Canadian Cancer Society http://www.cancer.ca

Jerant A, Johnson J, et al. Early detection and treatment of skin cancer. Am Fam Physician. 2000 Jul 15;62(2):357.

Saraiya M, et al. Preventing skin cancer. MMWR. 2003 Oct 17;52(RR15):1-12. Available at:
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5215a1.htm
Accessed February 25, 2015.

Squamous cell carcinoma. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed
Updated January 16, 2015. Accessed February 25, 2015.

Squamos cell carcinoma. American Academy of Dermatology website. Available at:
http://www.aad.org/skin-conditions/dermatology-a-to-z/squamous-cell-carcinoma
Accessed February 25, 2015.

Sunscreen FAQs. American Academy of Dermatology website. Available at: https://www.aad.org/media-resources/stats-and-facts/prevention-and-care/sunscreens. Accessed February 25, 2015.