Basal cell cancer occurs when skin cells undergo cancerous changes.

What is going on in the body?

Over 500,000 people a year in the U.S. are affected by basal cell carcinoma. Basal cell cancer begins in cells that have been damaged by exposure to the sun over many years. That is why most of these cancers occur on the head or neck. Middle-aged or older persons and those people who work outside are the most likely to develop these cancers. Damage by sunburn over and over again can cause skin cells to lose their ability to repair themselves. Cancer develops when the damage causes the cells to grow and divide abnormally. These cancerous cells can become tumors and will damage the skin around them.

What are the causes and risks of the disease?

Exposure to the sun over many years is the cause of basal cell cancer. The more often a person is exposed to the sun, the more likely it is that later in life an area of basal cell cancer will develop.