What It Is

closeup of ear displaying signs of squamous cell carcinomaSquamous cell carcinoma (also referred to as SCC) is the second most common form of skin cancer in Canada. Squamous cell carcinoma can develop from a precancerous growth or “sunspot” called an actinic keratosis. These actinic keratoses are rough, scaly growths ranging in colour from skin colored, pink to brown. They are found on sun-exposed parts of the body and can often be felt before they become visible. Up to one in 10 can become squamous cell carcinomas, sometimes within two years.

Treatment for squamous cell carcinoma must not be ignored, because the larger these tumours grow, the more dangerous they can become. This can lead to disfigurement and potentially require more extensive medical attention. A small percentage may spread (metastasize) to lymph nodes and other organs, with potentially fatal results.

Risk Factors

Fair-skinned people who freckle and burn easily are at greatest risk of squamous cell carcinoma. People who work outdoors or have hobbies with significant sun exposure (such as golfing, gardening and sailing) face an increased risk because of their extensive sun exposure.

In addition, people who have a weakened immune system (immunosuppressed) because of medications or organ transplantation (e.g. kidney, liver, heart, lung), as well as those with a blood cancers (e.g. CLL) are at a significantly higher risk for the development of squamous cell skin cancers. In these patients, squamous cell carcinoma often acts more aggressively by growing faster and having an increased risk of spreading in the body.


Squamous cell skin cancers appear as thickened, red scaly bumps or wart-like growths. They may also look like an open sore or crusted skin.  Sometimes they can become very painful to touch. This type of skin cancer may grow quickly over a period of a few weeks or more slowly over months.

Squamous cell carcinoma can occur on any part of the body but is most common on areas exposed to the sun such as the head, face, neck, shoulders, and extremities (i.e. arms, legs, backs of hands). Lesions that develop on the rim of the ear and the lip are often more aggressive and are prone to spreading to nearby lymph glands.


Chronic exposure to ultraviolet radiation from the sun or from tanning beds is the leading cause of squamous cell carcinoma. This exposure causes certain cells in the skin’s outer layer to grow out of control and become a tumour. Squamous cell carcinoma can also develop where the skin has been damaged by x-rays, chronic ulcers, burns, and some highly inflammatory rashes. It is not contagious.


The best way to avoid developing squamous cell carcinoma is to take steps to avoid unnecessary exposure to ultraviolet radiation.

  • Stay in the shade, especially between 10 a.m. and 4 p.m.
  • Avoid tanning or burning
  • Don’t use tanning beds
  • Wear protective clothing, including a broad-brimmed hat and sunglasses that block ultraviolet rays
  • Use a sunscreen with an SPF of 30 or greater and that protects against both UVA and UVB rays or says “broad spectrum” on the bottle
  • Examine your skin regularly and report any changes to your doctor

When detected early and treated promptly, squamous cell carcinoma is almost always curable and causes minimal damage. Treatment options depend on your age and medical condition, as well as the nature of the tumour.

Treatment options depend on the tumour (size, location, subtype) and the patient’s health status. Your dermatologist will discuss treatment options with you. Some treatment options include: surgical excision (removing the cancer surgically then suturing the area closed) or a procedure called electrodessication and curettage (where the cancer is removed by scraping and cauterizing the skin).

For more complicated tumours or those that arise on the head, neck, hands, feet or genitals, a specialized form of surgery called Mohs surgery is used. Performed by a Certified Dermatologist trained in this technique, Mohs surgery has a high success rate. It is indicated for tumors in sensitive areas or tumors that are recurrent.  Occasionally, radiation is used to treat squamous cell carcinoma.

For a comprehensive overview of treatment options, contact your dermatologist.

If left untreated, squamous cell carcinoma can spread, causing serious health problems. It can be fatal.

Skin of Colour

Squamous cell carcinoma is the most common form of skin cancer in Black Canadians. The association between sun exposure and squamous cell carcinoma development is less prominent in skin of colour compared to those with white skin. As a result, in skin of colour, squamous cell carcinoma more frequently develops in non-sun-exposed areas, such as the legs and feet or in the genital region. When compared to white skin, squamous cell carcinomas in skin of colour are more likely to occur following chronic inflammatory conditions or scarring processes as well as those who are chronically immunosuppressed.

People with skin of colour often present with more advanced squamous cell carcinomas — especially if they occur on scarred or inflamed skin. Because these advanced cancers are associated with lower survival rates, treatment outcomes in patients with skin of colour may be poorer. Those with skin of colour may present with more advanced disease due to delayed diagnosis, delayed presentation, or a tendency for cutaneous squamous cell carcinoma to be more aggressive in areas typically not exposed to the sun.