Basal Cell And Squamous Cell Carcinomas - Skin Cancer: Skin Health

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Basal cell and squamous cell carcinomas

These two types of skin cancer are generally not life-threatening and are treated in similar ways.

The most benign form of skin cancer — and the least likely to spread to other parts of the body — is basal cell carcinoma. It's also the most common form, accounting for about 80% of cases. Basal cell carcinoma originates in basal cells located deep in the epidermis. The most common cause of this cancer is cumulative damage from sun exposure. A basal cell carcinoma may first appear as a pearly pimple or bump, a white- or yellow-colored scar, or a scaly red patch. Some basal cell cancers appear as an ulcer that won't heal. Basal cell cancer is very slow-growing, and will not develop into the potentially fatal melanoma. Sunscreens do not protect against basal cell carcinoma, according to one large long-term study on the subject. The reason is not yet understood.

Another 16% of skin cancers are squamous cell carcinomas. This form of cancer arises from flat, scale-like cells in the epidermis. Although squamous cell cancer usually isn't fatal, it can be life-threatening if it spreads to lymph nodes or internal organs. But even then, the cure rate is around 50%. Four times more men than women develop squamous cell carcinoma. It usually starts as a small, scaly bump and grows slowly until it resembles an ulcer or wart. Squamous cell cancers frequently occur on the face, lips, ears, or backs of the hands, and they too result from cumulative sun damage. Early detection is key to preventing the spread of squamous cell cancer. Like basal cell cancer, it will not develop into melanoma. Long-term sunscreen use reduces the risk of squamous cell carcinoma by about 35%, according to one large study.

Treating basal cell and squamous cell cancers

Options for treating basal and squamous cell cancers are similar. Depending on the size and location of the tumor, both types can be surgically removed. The procedure involves removing the cancer and the tissue around it, called the margin, to ensure that all cancer cells have been removed. If they haven't, another procedure will be required. Most experienced dermatologists are quite skilled at estimating appropriate margins. The surgical scar can take several months to heal, especially if a tumor was removed from the face.

A technique called Mohs' micrographic surgery has the highest reported cure rate for basal and squamous cell cancers and is less likely than other forms of surgery to damage surrounding healthy skin. Named after Wisconsin surgeon Frederic Mohs, the technique consists of surgically removing cancerous tissue one layer at a time, and then immediately examining the specimen's entire surface area microscopically to see if there are any cancer cells at the outer edges of the tissue. If there are, more of the surrounding tissue can be removed. If not, only a small wound is left. This technique eliminates the guesswork from determining margins. Mohs' surgery is beneficial for cancers near the eyes and prominent areas of the face. In some cases, wounds from Mohs' surgery may not need surgical reconstruction.

Electrodesiccation and curettage — more commonly called scraping and burning — is a simple, effective treatment for very superficial basal and squamous cell carcinomas. The procedure uses a sharp scraping tool called a curette to scoop out the tumor and a small margin of surrounding skin. The area is then cauterized with an electric needle. The main drawback of this method is that there is no tissue left to examine to determine if all cancerous cells have been removed.

Other options include cryosurgery with liquid nitrogen, which is highly effective; laser surgery for superficial cancers; or treatment with fluorouracil or imiquimod cream, also for superficial cancers.

Last updated:	July 20, 2007