Skin Cancer Overview
Skin cancer is the most common of all human cancers, with 1 million people in the U.S. diagnosed each year with some type of the disease.
Cancer occurs when normal cells undergo a transformation and grow and multiply without normal controls. Here are the cancer basics:
- As the cells multiply, they form a mass called a tumor.
- Tumors are cancerous only if they are malignant. This means that they encroach on and invade neighboring tissues (especially lymph nodes) because of their uncontrolled growth.
- Tumors may also travel to remote organs via the bloodstream.This process of invading and spreading to other organs is called metastasis.
- Tumors overwhelm surrounding tissues by invading their space and taking the oxygen and nutrients they need to survive and function.
There are three major types of skin cancers: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. The first two skin cancers are grouped together as non-melanoma skin cancers. Other unusual types of skin cancer include Merkel cell tumors and dermatofibrosarcoma protruberans.
Here are the basics on skin cancers:
- The vast majority of skin cancers are basal cell carcinomas and squamous cells carcinomas. While malignant, these are unlikely to spread to other parts of the body. They may be locally disfiguring if not treated early.
- A small but significant number of skin cancers are malignant melanomas. Malignant melanoma is a highly aggressive cancer that tends to spread to other parts of the body. These cancers may be fatal if not treated early.
Like many cancers, skin cancers start as precancerous lesions. These precancerous lesions are changes in skin that are not cancer, but could become cancer over time. Medical professionals often refer to these changes as dysplasia. Some specific dysplastic changes that occur in skin are as follows:
- Actinic keratosis is an area of red or brown, scaly, rough skin, which can develop into squamous cell carcinoma.
A nevus is a mole, and abnormal moles are called dysplastic nevi. These can develop into melanoma over time.
- Moles are simply growths on the skin that rarely develop into cancer. Most people have 10 to 40 moles on their body that can be identified as flat or raised, smooth on the surface, round or oval in shape, pink, tan, brown or skin-colored, and no larger than a quarter-inch across. If a mole on your body looks different from the others, ask your health care provider to take a look at it.
- Dysplastic nevi, or abnormal moles, are not cancer, but they can become cancer. People sometimes have as many as 100 or more dysplastic nevi, which are usually irregular in shape, with notched or fading borders. Some may be flat or raised, and the surface may be smooth or rough ("pebbly"). They are often large, at a quarter-inch across or larger, and are typically of mixed color, including pink, red, tan, and brown.
Recent studies show the number of skin cancer cases in the U.S. growing at an alarming rate. Fortunately, increased awareness on the part of Americans and their health care providers has resulted in earlier diagnosis and improved outcomes.