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Skin Cancer

Squamous Cell Carcinoma

Squamous cell carcinoma ranks second behind basal cell carcinoma as the most common type of skin cancer. It occurs when abnormal squamous cells in the outer layer of skin (the epidermis) multiply.

It is important to note that squamous cells also exist in the outer layers of tissue covering internal organs, such as the lungs. Though it is uncommon, squamous cell carcinoma can occur in these areas as well.

The Dangers of Squamous Cell Carcinoma

While not as lethal as melanoma, squamous cell carcinoma is definitely more serious than basal cell carcinoma. Although the chances of squamous cell carcinoma metastasizing is low—about 3% to 9%—it can occur within a year of diagnosis if left untreated. Like basal cell carcinoma, squamous cell carcinoma can spread into surrounding skin and bone tissue, but it can also spread into nearby lymph nodes and other organs depending on its location. This could require more extensive treatment. However, when caught early, most squamous cell carcinoma cases can be cured with a single in-office procedure.

The Prevalence of Squamous Cell Carcinoma

Although squamous cell carcinoma occurs less frequently than basal cell carcinoma, cases in the United States are steadily climbing. The total reported cases increased by nearly 200% over the past few decades.
An estimated 1.8 million cases of squamous cell carcinoma are diagnosed annually in the U.S. This is the equivalent of about 200 cases diagnosed every hour.

How Squamous Cell Carcinoma Forms

Exposure to ultra-violet radiation from the sun or tanning beds is a key factor in nearly all skin cancers, including squamous cell carcinoma. UV radiation can damage DNA within skin cells. This triggers a chain of abnormal cellular activity, leading to the formation of cancer.

According to the American Academy of Dermatology, using a tanning bed even once can increase squamous cell carcinoma risk by 67%.

Skin cancers, including squamous cell carcinomas, typically emerge on sun-exposed areas of the body such as the face, ears, neck, lips, and backs of hands. Squamous cell carcinoma may also develop in scars or chronic skin sores elsewhere. Factors that increase one’s risk include having light skin, eyes and hair, a history of burns on the skin, previous cancers, and living in a high altitude or a sunny region like California. People over 50 are more likely to be diagnosed with skin cancer because of their accumulated sun exposure.

There may also be a link between squamous cell skin cancer and some types of the human papilloma virus (HPV). This is a current and ongoing topic of scientific study.

What Squamous Cell Carcinoma Looks Like

In its precancerous stages, squamous cell carcinoma can look similar to natural signs of aging to an untrained eye. Things like a rough, reddened patch (sometimes called actinic keratosis), a brown spot that looks like an age spot, a wart, a sore with a crusty edge, or a sore forming in an old scar could all be warning signs of squamous cell carcinoma. That’s why an annual skin cancer check by a board-certified dermatologist is your best prevention strategy for squamous cell carcinoma and other skin cancers.

Treating Squamous Cell Carcinoma

If your biopsy affirms cancer is present, your California Skin Institute board-dermatologist will discuss a treatment plan with you. This plan will be designed to address factors such as the size and stage of the cancer, your medical history, and personal preferences.

In most cases, the cancer can be removed by in-office surgical procedures—either surgical excision or Mohs surgery. Destroying the cancer cells with cryotherapy, a freezing treatment of liquid nitrogen, may be another option.


This is to be used only as an educational piece. Individuals should not use it to self-diagnose a skin condition or problem.

Treatments for Squamous Cell Carcinoma

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