Skin cancer is the most common type of cancer in Canada. It is estimated that more than 78,000 Canadians develop non-melanoma skin cancer each year, and that number continues to rise.
There are 3 main types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and melanoma. This article deals with the first two types, which together are known as "non-melanoma skin cancer." Unlike melanoma, non-melanoma skin cancer has a low mortality rate and is often highly treatable. For information on melanoma, please see our Melanoma article.
Basal cell carcinoma (BCC) is the most common skin cancer and is also the most common cancer. It grows from the basal (bottom) layer of the epidermis (the outer layer of the skin). It almost always appears on sun-exposed skin, such as the forehead, hands, lips, or tops of the earlobes. BCC makes up about 75% of all non-melanoma skin cancers. There are 3 main types of BCC:
- Superficial basal cell carcinoma (sBCC) often appears on the chest and upper body (torso) and possibly on the face. Commonly, it is a well-defined, scaly patch that looks similar to eczema. There is also often a thin, raised border that is pearl-coloured around the affected patch of skin.
- Nodular BCC appears on areas exposed to the sun, including the head and neck. It appears as an elevated bump of skin that is usually pearl-coloured or pink.
- Morpheaform BCC appears as an ivory scar in areas that have never been injured or operated on. The tumour appears slightly raised and waxy, and is often white or yellowish in colour. The borders of the tumour are not distinct.
There are also two more unusual types of BCC: pigmented BCC (similar to nodular BCC, but with black and brown pigmented areas) and cystic BCC (bluish-grey with a fluid-filled center).
Squamous cell carcinoma is less common than basal cell carcinoma, but it is the second-most-common skin cancer. It grows from the top layers of skin, and is also found most often in sun-exposed areas.
Other types of non-melanoma skin cancer, such as Merkel cell carcinoma, Kaposi's sarcoma, or cutaneous T-cell lymphoma, are known as rare skin tumours and make up about 1% of non-melanoma skin cancers.