Squamous Cell Carcinoma

By Ashley Henshaw. May 7th 2016

According to the Skin Cancer Foundation, skin cancer is the most common form of cancer in the United States. Of the many types of skin cancer, squamous cell carcinoma is the second most common form of skin cancer with about 700,000 cases diagnosed each year. In this article, we’ll provide the details about this type of skin cancer, including ways to prevent and identify it.


Squamous cell carcinoma is a type of nonmelanoma skin cancer. Of the two main types of skin cancer – nonmelanoma and melanoma – nonmelanoma is less aggressive and more common. It occurs when abnormal cells located in the skin’s upper layer, which is composed mostly of squamous cells, begin to grow uncontrollably.

Typically, this type of skin cancer occurs in areas that are frequently exposed to ultraviolet (UV) radiation, such as the face, neck, scalp, arms, legs, the backs of the hands, the lower lip or the rim of the ear. However, it may also occur in areas which are not exposed to UV light, such as the genitals, the anus and the inside of the mouth.


The appearance of a squamous cell carcinoma tumor may vary. The most common forms of these types of growths (and the areas on which they are normally found) include:

  • Flat lesions with a scaly crust (face, neck, ears, arms or hands)
  • Firm red nodules that may bleed (face, neck, ears, arms, hands, lower lip)
  • Flat white patch or ulcer (inside the mouth)
  • Raised red patch (genitals or anus)
  • Ulcerated sore (genitals or anus)
  • New raised area or ulcer on an existing scar or ulcer (anywhere)

Because squamous cell carcinomas develop slowly, they may be hard to identify. The warning signs usually include indications of sun damage, such as wrinkling, changes in pigmentation or loss of elasticity, so pay close attention to any areas showing these signs.


Exposure to UV radiation is the cause for most cases of squamous cell carcinoma. The condition develops due to the fact that UV radiation (whether from sun or tanning beds and lamps) damages the DNA in an individual’s skin cells. The more damage to the DNA, the more likely the skin cells will grow out of control and develop a squamous cell carcinoma.

In addition to exposure to UV light, there are also a few other factors which may cause this type of cancer, including:

  • HPV: The human papillomavirus (HPV) is a sexually transmitted disease that has over 100 strains, some of which may lead to squamous cell carcinoma.
  • Immunosuppressant drugs: People who take these drugs to prevent organ rejection after a transplant often develop squamous cell carcinomas. The skin cancer may not show up for years after the transplant occurs.
  • Therapeutic radiation: People who receive radiation treatments for psoriasis, acne or ringworm may develop this type of skin cancer.
  • Arsenic: This chemical toxin can cause many types of cancer, including squamous cell carcinoma. People who drink contaminated water or live near smelting plants are more likely to ingest arsenic.

Risk Factors

An individual’s risk for squamous cell carcinoma is directly related to their level of exposure to the causes of this type of cancer. For most people, the biggest indicator of their risk is their level of exposure to UV radiation from the sun or from tanning beds and lamps. High exposure to UV light at a young age increases the risk significantly. To learn more about the risks of UV radiation from tanning beds and lamps, read Dangers And Health Risks Of Tanning.

Other risk factors for squamous cell carcinoma include:

  • Having fair skin
  • Being 45 years or older
  • Being male
  • Personal history of skin cancer
  • Family history of skin cancer
  • Smoking
  • Having a weakened immune system
  • Having a large scar
  • Having a skin infection
  • Having an inflammatory skin disease, such as psoriasis
  • Having xeroderma pigmentosum, a rare genetic disorder which causes extreme sensitivity to sunlight


There are several ways to protect yourself against squamous cell carcinomas, most cases of which can be prevented. These preventative methods include:

  • Apply sunscreen: Put on a sunscreen that blocks both UVA and UVB rays and has an SPF of at least 15 any time you go out in the sun. You should apply it generously and reapply every two hours (more if you’re sweating or swimming). Don’t forget to use sunscreen all year-round, not just in the summer.
  • Wear protective clothing: Wearing clothing to cover your skin is another way to protect against UV radiation. Make sure your clothes are tightly woven. Cover your arms and legs if possible, and wear a wide-brimmed hat to cover your face, ears and neck. Wear sunglasses as well to protect your eyes.
  • Avoid midday sun: Regardless of the season, the sun is strongest between about 10 a.m. and 4 p.m. Avoid being out in the sun for very long during these hours if possible. Remember that clouds don’t offer much protection from UV rays and that sunlight is more intense when you’re near water, sand or snow.
  • Don’t use tanning beds or lamps: The risk of squamous cell carcinoma is more than doubled for a person who uses a tanning bed regularly. Use self-tanning lotions or sprays instead. For more safe and useful tips on tanning, check out Safe-Self Tanning Tips For A Summer Look.
  • Check your skin regularly: Keep an eye out for new growths or changes in moles, freckles, bumps, scars and birthmarks. Check your scalp, ears, buttocks and genitals as well.
  • Understand drug side effects: Some medications (including ibuprofen, many acne medications and some antibiotics) make your skin more sensitive to sunlight. Take extra precautions if this is a side effect of a medication you’re taking.


Most squamous cell carcinomas are curable, particularly if detected early. The treatment depends on the size, location and aggressiveness of the tumor, but many can be treated with minor surgery. Treatment options include:

  • Excision: the cancerous tissue is cut out.
  • Mohs surgery: the tumor is removed layer by layer until a layer with no abnormal cells is reached.
  • Freezing: liquid nitrogen is applied to remove cancerous cells.
  • Laser therapy: a laser is applied to vaporize growths.
  • Radiation therapy: radiation is applied to kill larger tumors.
  • Chemotherapy: topical creams or lotions with anti-cancer agents are applied to the skin.

Squamous cell carcinoma is one of the most easily treatable and preventable types of skin cancer. However, it can still be deadly if it isn’t detected or treated early enough. Make sure you protect yourself from UV radiation and perform regular examinations of your skin to help prevent this type of cancer. Also, be sure to notify your doctor immediately if you discover any skin irregularities.


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