Basal cell carcinoma
Of the more than 3 million cases of skin cancer diagnosed every year, more than 80 percent are basal cell carcinoma, according to the American Cancer Society. These cancers develop within the basal cell layer of the skin, the lowest part of the epidermis.
This type of skin cancer tends to occur in areas of the skin that receive the most exposure to the sun, like the head and neck. Basal cell cancers usually grow slowly, and it is rare for them to spread, or metastasize, to nearby lymph nodes or even to more distant parts of the body. But this may occur if it is left untreated, so early detection and treatment are important.
Basal cell cancers may also recur in the same location where the original cancer formed. Patients who have had basal cell carcinoma once have an increased risk of developing a new basal cell cancer elsewhere. As many as 50 percent of these patients may develop a new basal cell carcinoma within five years of their first diagnosis.