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Squamous cell carcinoma
Definition
Squamous cell carcinoma is a type of skin cancer.
Skin cancer falls into two groups: nonmelanoma and melanoma. Squamous cell is a type of nonmelanoma skin cancer.
Alternative Names
Cancer - skin - squamous cell; Skin cancer - squamous cell; Nonmelanoma skin cancer - squamous cell; NMSC - squamous cell; Squamous cell skin cancer
Causes
Squamous cell cancer may occur in normal skin or in skin that has been injured or inflamed. Most skin cancers occur on skin that is regularly exposed to sunlight or other ultraviolet radiation.
The earliest form of squamous cell skin cancer is called Bowen's disease (or squamous cell in situ). This type has not spread to nearby tissues.
Actinic keratosis is a precancerous skin lesion that rarely may become a squamous cell cancer.
Risks for squamous cell skin cancer include:
- Having light-colored skin, blue or green eyes, or blond or red hair
- Long-term, daily sun exposure (such as in people who work outside)
- Many severe sunburns early in life
- Older age
- Having had many x-rays
- Chemical exposure
Symptoms
Squamous cell skin cancer usually occurs on the face, ears, neck, hands, or arm. It may occur on other areas.
The main symptom is a growing bump that may have a rough, scaly surface and flat reddish patches.
The earliest form appears as a scaly, crusted, and large reddish patch (often larger than 1 inch).
A sore that does not heal can be a sign of squamous cell cancer. Any change in an existing wart, mole, or other skin lesion could be a sign of skin cancer.
Exams and Tests
Your doctor will check your skin and look at the size, shape, color, and texture of any suspicious areas.
If your doctor thinks you might have skin cancer, a piece of skin will be removed and sent to a lab for examination under a microscope. This is called a skin biopsy. There are different types of skin biopsies.
A skin biopsy must be done to confirm squamous cell skin cancer or other skin cancers.
Treatment
Treatment depends on the size and location of the skin cancer, how far it has spread, and your overall health. Some squamous cell skin cancers may be more difficult to treat.
Treatment may involve:
- Excision: Cutting out the skin cancer and stitching the skin together
- Curettage and electrodesiccation: Scraping away cancer cells and using electricity to kill any that remain; it is used to treat cancers that are not very large or deep
- Cryosurgery: Freezing the cancer cells, which kills them
- Medication: Skin creams containing imiquimod or 5-fluorouracil for superficial (not very deep) basal cell cancer
- Mohs surgery: Removing a layer of skin and looking at it immediately under a microscope, then removing many layers of skin until there are no signs of the cancer; usually used for skin cancers on the nose, ears, and other areas of the face.
- Photodynamic therapy: Treatment using light may be used to treat Bowen's disease (BD).
Radiation may be used if the squamous cell skin cancer has spread to organs or lymph nodes, or if the cancer cannot be treated with surgery.
For more treatment information, see: Actinic keratosis
Outlook (Prognosis)
How well a patient does depends on many things, including how quickly the cancer was diagnosed. Most of these cancers are cured when treated early.
Some squamous cell cancers may return.
If you have had skin cancer, you should have regular check-ups so that a doctor can examine your skin. You should also examine your skin once a month. Use a hand mirror to check hard-to-see places. Call your doctor if you notice anything unusual.
Possible Complications
Squamous cell cancer spreads faster than basal cell cancer, but still may grow slowly. It may spread to other parts of the body, including internal organs.
When to Contact a Medical Professional
Call for an appointment with your health care provider if you have a sore or spot on your skin that changes in:
- Appearance
- Color
- Size
- Texture
You should also call if an existing spot becomes painful or swollen, or if it starts to bleed or itch.
Prevention
The best way to prevent skin cancer is to reduce your exposure to sunlight. Ultraviolet light is most intense between 10 a.m. and 4 p.m., so try to avoid sun exposure during these hours. Protect the skin by wearing hats, long-sleeved shirts, long skirts, or pants.
Always use sunscreen:
- Apply high-quality sunscreens with sun protection factor (SPF) ratings of at least 15, even when you are only going outdoors for a short time.
- Apply a large amount of sunscreen on all exposed areas, including ears and feet.
- Look for sunscreens that block both UVA and UVB light.
- Use a waterproof formula.
- Apply sunscreen at least 30 minutes before going outside, and reapply it frequently, especially after swimming.
- Use sunscreen in winter, too. Protect yourself even on cloudy days.
Other important facts to help you avoid too much sun exposure:
- Avoid surfaces that reflect light more, such as water, sand, concrete, and white-painted areas.
- The dangers are greater closer to the start of summer.
- Skin burns faster at higher altitudes.
- Avoid sun lamps, tanning beds, and tanning salons.
Examine the skin regularly for unusual growths or skin changes.
References
American Cancer Society. Cancer Facts and Figures 2006. Atlanta, GA: American Cancer Society; 2006.
National Comprehensive Cancer Network. NCCN Medical Practice Guidelines and Oncology: Basal Cell and Squamous Cell Cancers. V.1.2009. Accessed July 15, 2009.
Hexsel CL, Bangert SD, Hebert AA, et al. Current sunscreen issues: 2007 Food and Drug Administration sunscreen labeling recommendations and combination sunscreen/insect repellant products. J Am Acad Dermatol. 2008;59:316-323.
Lautenschlager S, Wulf HC, Pittelkow MR. Photoprotection. Lancet. 2007;370:528-537.
Ridky TW. Nonmelanoma skin cancer. J Am Acad Dermatol. 2007;57:484-501.
Wood GS, Gunkel J, Stewart D, et al. Nonmelanoma skin cancers: basal and squamous cell carcinomas. In: Abeloff MD, Armitage JO, Nierderhuber JE, Kastan MB, McKenna WG, eds. Abeloff's Clinical Oncology. 4th ed. Philadelphia, PA: Churchill Livingstone; 2008:chap 74.
Reviewed By: Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
