Microscope lenses close-up

Skin Cancer

Cancer is the abnormal growth of cells at an uncontrolled and unpredictable rate. The cancer tissue usually grows at the expense of surrounding normal tissue. In the skin, the most common types of cancer are basal cell carcinoma and squamous cell carcinoma. The names reflect the cell within the skin from which the particular type of skin cancer originates.

In the Mohs Surgery Unit, we treat basal cell carcinomas, squamous cell carcinomas, and some much rarer skin tumors. Malignant melanoma or a “cancerous mole” is a rarer type of skin cancer which usually appears as a dark colored spot or bump on your skin and which slowly enlarges. As it is usually treated by means other than Mohs Surgery, we will omit discussion of malignant melanoma from this booklet.

What are basal cell and squamous cell carcinoma?

Both basal cell carcinoma(BCC) and squamous cell carcinoma(SCC) arise from the outer layer of skin called epidermis. BCC occurs primarily on the head and neck areas of the body, while SCC may occur there as well as other sun exposed skin such as arms, legs and hands. You will see pictures of skin cancers on this web site and elsewhere that will reinforce to you how varied the appearance may be. It is important to realize that new or changing lesions on your skin should be brought to the attention of your dermatologist.

There are several different subtypes of basal cell carcinoma and squamous cell carcinoma. It is important to distinguish these types prior to treatment, as different therapies may be required. For this reason, a biopsy is usually performed prior to treatment of any kind. Like many other cancers, the cause of skin cancer is unknown. Genetic predisposition is an important risk factor and it is very common for multiple members of the same family to have a history of skin cancer.

The most common association with skin cancer is long-term exposure to sunlight. This is why skin cancers develop most often on the face and the arms (sun-exposed body parts). They occur more commonly in fair-skinned people than dark-skinned people. In the United States, skin cancer occurs more frequently in the southern (sun-belt) states. Superficial x-rays, which were used many years ago as a treatment for certain skin diseases, may result in skin cancer many years later. X-ray pictures, such as chest x-rays, do not cause skin cancer. Trauma (scars), certain chemicals, and certain rare inherited diseases may also contribute to the development of skin cancer.

The abnormal growth (cancer) originates in the uppermost layer of the skin. The cancer then grows downward, forming root and finger-like projections under the surface of the skin. Unfortunately, at times these roots are so subtle that they cannot be seen without the aid of a microscope. Therefore, what you see on your skin is sometimes only a small portion of the total tumor.

How successful is the treatment of skin cancer?

Initial treatment of skin cancers has a success rate greater than 90%. Methods commonly employed to treat skin cancer include excision (surgical removal and stitching), curettage and electrodesiccation (scraping and burning with an electric needle), cryosurgery (freezing), and radiation therapy (“deep x-ray”). The method chosen depends upon several factors, such as the microscopic type of tumor, the location and size of the cancer, as well as a history of treatment failure(recurrent skin cancer) . You may have had one or more of these methods of treatment before coming for Mohs Surgery.

The success rate of treating a recurrent skin cancer by the above non-Mohs means ranges from 50-70%. The success rate for Mohs Surgery, even in treating recurrent lesions, is about 98%. Mohs Surgery is very time consuming and requires a highly trained team of medical personnel. Most skin cancers can be easily and effectively treated by the other methods listed above. Mohs Surgery is reserved for recurrent skin cancers or for primary skin cancers which are difficult to treat initially with other therapies.

Patient Information & Education

Find more information about Mohs Surgery and Skin Cancer in the following topics below.