Skin cancer is a disease in which cancer cells form in the tissues of the skin. The skin has several layers, but the two main layers are the upper layer, called the epidermis, and the lower or inner layer, called the dermis. Skin cancer begins in the epidermis, which is made up of three kinds of cells.
These three cells are squamous cells, which are thin, flat cells that form the top layer of the epidermis; basal cells, which are the round cells found under the squamous cells; and melanocytes which are cells that make melanin and are found in the lower part of the epidermis.
The most common types of non-melanoma skin cancers are basal cell carcinoma and squamous cell carcinoma. Non-melanoma skin cancers rarely spread to other parts of the body.
Risk factors for non-melanoma skin cancer can include factors such as being exposed to natural sunlight or artificial sunlight (such as from tanning beds) over long periods of time.
Particular attributes which increase a person’s risk for these skin cancers include fair skin that freckles and burns easily, does not tan, or tans poorly; blue, green or light-coloured eyes; red or blond hair.
Past treatment with radiation or a weakened immune system can also lead to skin cancer. Gene mutations also can play a role in the development of some skin cancers.
Non-melanoma skin cancers often present as a change in the skin. Non-melanoma skin cancers can appear as a lump or wart-like growth with a rough, scaly surface, or as a flat, reddish patch. A sore that does not heal is another indication of skin cancer.
Areas of skin that look raised, smooth, shiny and look pearly should also be observed. If there is a growth it may bleed easily, or crust or ulcerate or the skin. It may be firm and look like a scar, or be white, yellow, or waxy.
The procedures used to examine the skin, and test for non-melanoma skin cancer include:
Skin exam: A doctor or nurse will check the skin for bumps or spots that look abnormal in colour, size, shape, or texture.
Skin biopsy: All or a section of the abnormal-looking growth is cut from the skin and viewed under a microscope by a pathologist to check for signs of cancer.
Treatment options for Basal Cell Carcinoma skin cancer and Squamous Cell Carcinoma can include a simple surgical removal of the cancerous tissue or involve a procedure called Mohs Micrographic Surgery where individual layers of cancer tissue are removed and examined under a microscope one at a time until all cancer tissue has been removed.
A high powered laser beam that can cut through tissue can also be used to surgically remove the cancer.
Curettage and electrodessication where the surgeon removes the tissue by scraping it, then using an electrode to destroy any remaining cancer cells, is also an option. Therapies to shrink or kill the cancer can include radiotherapy and chemotherapy. Cryotherapy is another treatment option where extremely cold liquid, or an instrument called a cryoprobe, is used to freeze and destroy abnormal tissue.