Squamous Cell Carcinoma (SCC)

Overview

Squamous cell carcinoma (SCC) is a cancer that forms in squamous cells. Squamous cells are thin cells found in the most superficial layer of the skin (epidermis) and other mucous membranes in the body. Cancer cells grow as a mass (tumor) that may also invade other tissues or spread to other parts of the body.

SCC is a major type of skin cancer. SCC usually develops on sun-exposed parts of the body, especially the head, neck, hands, and legs, but it may develop elsewhere. Other sites can include the lips, mouth, lung, digestive tract, bladder, anus, and genitals.

Early stages of SCC are highly curable with minor surgery. Rarely, SCC spreads (metastasizes) beyond the skin to other areas of the body. This form of advanced cancer requires much more extensive treatment.

Causes and Risk Factors

Illustration of skin cross-section showing different layers of skin

Ultraviolet (UV) radiation from the sun is the predominant cause of skin cancer. Cumulative sun exposure and the use of tanning beds are the major factors. Anyone can develop squamous cell carcinoma; however, certain Individuals have an increased risk.

Individuals with light-colored skin, freckled skin, blond hair, red hair, and light eyes have a greater risk for skin cancer. People with dark skin are more likely to develop skin cancer in parts of the body that are not exposed to the sun, such as the feet.

Areas of skin with scars, burns, or ulcers have a higher risk of developing SCC. Other risk factors include tobacco, tar exposure, cancer-causing chemicals (such as arsenic and insecticides), radiation exposure, and human papillomavirus (HPV). Additionally, anyone with a weak immune system or an organ transplant has an increased risk of SCC.

Symptoms of SCC

Squamous cell carcinoma commonly occurs in areas of skin with high sun exposure such as the face, scalp, head, neck, ears, hands, arms, and legs.

Common symptoms include the following:

  • Firm red growth or lump
  • Scaly lesion that bleeds and become crusty
  • Open sore or rough patch of the skin, lip, mouth, anus or genitals.

Diagnosis and Treatment

squamous cell carcinoma on noseA biopsy is the main method for diagnosing SCC. A physician performs a biopsy by cutting out the growth for examination with a microscope.

When squamous cell carcinoma is diagnosed, the physician determines the extent (stage) of the disease by evaluating the depth of the cancer and whether it has spread. Treatment for SCC depends on the cancer’s stage. Early SCC is highly curable, whereas advanced SCC, which has spread to lymph nodes or metastasized to other sites, is more difficult to treat.

Stages of SCC

  • Stage 0 involves only the surface of the skin.
  • Stage I is ≤ 2 cm in width.
  • Stage II is > 2 cm in width.
  • Stage III involves the underlying cartilage, muscle, or bone, or has spread to lymph nodes.
  • Stage IV has metastasized to distant locations in the body.

Treatment of SCC

  • Surgical excision involves cutting out the entire tumor and some surrounding normal tissue.
  • Mohs surgery requires an excision of a thin layer of skin that is examined with a microscope. If cancers cells are present at the tissue edge, additional tissue is removed. These steps are repeated until the skin samples are free of cancer.
  • Curettage and electrodesiccation involves scraping away the tumor and applying electricity to destroy residual cancer cells. This treatment is only for early tumors.
  • Cryosurgery involves the use of liquid nitrogen to freeze and destroy cancer cells. This treatment is used in early cancers.
  • Photodynamic therapy (PDT) uses a chemical and special light to destroy cancer cells.
  • Laser treatment is used, rarely, for certain types of early cancers.
  • Radiation therapy treats deep cancers that cannot be removed with surgery.
  • Systemic chemotherapy is used for advanced cancer that has spread to the lymph nodes or other parts of the body.
  • Topical chemotherapy cream is only used in the very earliest stage of SCC.

Prevention

Protecting skin from the sun is the most important way to prevent any type of skin cancer. Preventive measures include avoidance of direct sun exposure during the hours of 10 am to 3 pm (when UV radiation is highest) and use of sunscreen with sun protection factor (SPF) 30 or higher. Additionally, tanning bed use and smoking should be avoided.

Individuals should routinely perform a self-examination of the skin to check for new growths on the face, neck, ears, arms, legs, hands, feet, trunk, mouth, genitals, and buttocks. An examination by a health care professional is also important for detection of early signs of cancer.

Sources

  • Skin Cancer: Basal and Squamous Cell. American Cancer Society website. http://www.cancer.org/cancer/skincancer-basalandsquamouscell/detailedguide/index. Accessed May 22, 2014.
  • Squamous Cell Carcinoma. American Academy of Dermatology website. http://www.aad.org/dermatology-a-to-z/diseases-and-treatments/q---t/squamous-cell-carcinoma. Accessed May 22, 2014.
  • Sun Exposure and Skin Cancer. Cleveland Clinic website. http://my.clevelandclinic.org/disorders/skin_cancer/hic_sun_exposure_and_skin_cancer.aspx. Accessed May 22, 2014.
  • What You Need to Know About Melanoma and Other Skin Cancers. National Cancer Institute at the National Institutes of Health website. http://www.cancer.gov/cancertopics/wyntk/skin/page4. Accessed May 22, 2014.