Skin Cancer Rate Increasing

Medical Author: William C. Shiel Jr., MD, FACP, FACR

The two most common kinds of skin cancer are basal cell carcinoma and squamous cell carcinoma. (Carcinoma is cancer that begins in the cells that cover or line an organ.) Basal cell carcinoma accounts for more than 90% of all skin cancers in the United States. It is a slow-growing cancer that seldom spreads to other parts of the body. Squamous cell carcinoma also rarely spreads, but it does so more often than basal cell carcinoma. However, it is important that skin cancers are found and treated early because they can invade and destroy nearby tissue.

Basal cell carcinoma and squamous cell carcinoma are sometimes called non-melanoma skin cancer. Another type of cancer that occurs in the skin is melanoma, which begins in the melanocytes.

There is popular concern that the rates of both nonmelanoma and melanoma skin cancers are more frequent in recent decades than in the past. Research published in Archives of Dermatology (1997;133:735-740) demonstrates a clear increase in squamous cell skin cancers.

Dr. Darryl T. Gray and colleagues from the Mayo Clinic reviewed 1630 dermatology records dating from 1984 to 1992 to discover 511 cases of squamous cell cancer. They plotted the trend which clearly shows an increasing rate of first diagnosis of this form of skin cancer over this period.

Further, the authors of the study found that the skin cancers had a tendency to appear on the head, neck, and upper extremities. This is consistent with the notion that sun exposure is a causative factor in this form of cancer.