Skin Cancer

What Is Skin Cancer? 

Cancer is the uncontrolled growth of abnormal cells at an unpredictable rate. As cancer tissue grows, normal healthy tissue surrounding the tumor is destroyed.  The most common cause of skin cancer is long-term exposure to sunlight. Skin cancers therefore occur most often on sun-exposed areas of the body, particularly the head and neck.  Skin cancer also occurs more commonly in people with fair complexions who sunburn easily.

Superficial X-rays, used many years ago for treatment of certain skin diseases, may contribute to the development skin cancer many years later. Trauma (scars), certain chemicals, and certain rare inherited diseases may also contribute to the development of skin cancer.

In the skin, 96% of all new cases of skin cancer are basal cell carcinoma (80%) and squamous cell carcinoma (16%). There are about 1.3 million cases each year in the United States.  Basal cell carcinoma and squamous cell carcinoma are distinct from melanoma, a less common type of skin cancer.

What are Basal Cell and Squamous Cell Carcinoma? 

Basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) grow from specific cells in the outermost layer of the skin. The tumor may begin as a small bump that looks like a pimple. It gradually enlarges, and sometimes bleeds. The cancer may appear red, pearly, scaly, flesh-colored, or darker than the surrounding skin.  BCC almost never spreads to distant parts of the body. SCC has a higher risk for spread (metastasis).   Risk for metastasis is increased for larger, untreated tumors and in patients who are immunosuppressed.

There are several subtypes of BCCs and SCCs.  For example, some grow downward, forming “roots” or projections underneath the surface of the skin. What you see on your skin may therefore be only a small portion of the whole tumor.  It is important to distinguish the different cancer subtypes prior to treatment, as different therapies may be required. The diagnosis is made by a skin biopsy followed by examination under a microscope.

How Successful Is the Treatment of Skin Cancer? 

Initial (primary) treatment of most skin cancers has a success rate greater than 90%.  Cure rate depends in part on the type of growth pattern, the size, and location of the tumor.  Methods commonly used to treat skin cancer include surgical excision (surgical removal and stitching), curettage and electrodesiccation (scraping and burning with an electric needle), cryosurgery (freezing), and radiation therapy. The method chosen depends upon several factors including the microscopic subtype of tumor, the location and size of the cancer, and previous therapy. You may have had one or more of these methods of treatment before coming for Mohs surgery.

The success rate in treating a recurrent (previously treated) skin cancer by the above conventional methods is often as low as 50%. The success rate for Mohs surgery in treating recurrent lesions is about 95-98%.

Mohs micrographic surgery (discussed in detail below) is a highly specialized skin cancer surgery technique which requires a trained team of medical personnel. The majority of tumors treated with Mohs surgery are complex basal and squamous cell carcinomas.  In some circumstances, Mohs surgery can be used to treat less common tumors, including some superficial melanomas.

Skin cancers are complex when:

  • the cancer is in an area where preservation of healthy tissue is critical to maximize function and cosmetic result (eyelids, nose, ears, lips, hands)
  • the cancer is in an area of higher tumor recurrence (ears, lips, nose, eyelids, temples)
  • the cancer was incompletely treated, or was previously treated and is recurrent
  • the cancer is large
  • the edges of the cancer cannot be clearly defined
  • scar tissue exists in the area of the cancer
  • the cancer grows in an area of prior radiation therapy
  • the patient is immunosuppressed (organ transplant, HIV infection, chronic lymphocytic leukemia)
  • the patient is prone to getting multiple skin cancers (including genetic syndromes such as basal cell nevus syndrome and xeroderma pigmentosa