The radiation beam is designed to maximally irradiate the skin while avoiding the underlying structures. The area of treatment includes the tumor with a margin or surrounding normal tissue. Usually a one centimeter margin is sufficient and rarely does one need to have a 2 cm. Adjacent uninvolved structures are easily shielded. Expected, but transient side effects limited to the field of radiation include erythema and less frequently scabbing.
Complete healing occurs within two to three weeks.
Normal anatomy is left in place and as a result, function and cosmetic outcome is usually excellent. Significant late complications are negligible. In a large series of 2000 skin cancers treated with radiation there were no radiation related second malignancies with follow up to 25 years. Most carcinomas of the skin are ideally suited for treatment with radiation. Exceptions include tumors arising in previously irradiated skin or in burn scars.