Skin cancer. Basal cell carcinoma (BCC), or rodent ulcer, on the cheek of a middle aged man. This is the most common form of skin cancer among fair- skinned people. It mostly affects the elderly, although in recent years the average age of onset has steadily decreased. It usually appears on the face and is thought to be caused by the ultraviolet radiation in sunlight. It slowly destroys surrounding tissues, but seldom spreads to other parts of the body. Treatments for basal cell carcinoma include radiotherapy, cryotherapy, cauterization and surgical excision.