Skin cancer is usually treated with surgery; often, Mohs’ excision is used for more advanced tumors and for those that are recurrent after prior excision. Tumors that are located on or around structures that would be difficult to reconstruct after resection, such as the eyelids, external ears, nose, and lips, may be treated with radiation therapy.
Before any treatment is started, the recommended treatment, the reasons it is recommended, the procedures to be carried out, the expected or possible side effects or complications, and the expected benefits are all explained to the patient and family. The patient must give permission for treatment, based on this knowledge (“informed consent”), before treatment is given.
Radiation may be given with either an interstitial implant or external beam treatments. Most tumors are treated with low energy (orthovoltage) X rays; specially designed lead masks are placed directly on the skin surface to block out the normal tissues that don’t need to be treated while allowing the tumor to be effectively irradiated. Alternatively, electron beam radiation may also be used, but it is more difficult to achieve optimal dose distributions with electron beam compared with the orthovoltage X-ray beams.
Radiation therapy is also indicated for patients with advanced cancers that involve structures such as nerves and/or bone that are at high risk for recurrence after surgical removal of the tumor.
The likelihood of cure after radiation therapy for early-stage skin cancer exceeds 90%; the cure rate is in the range of 50-60% for patients with advanced skin cancers.
Radiation therapy may also be used for patients who have skin cancers that metastasize to lymph nodes, such as in the neck or near the salivary glands (parotid gland). The chance of cure with radiation therapy after excision of these nodes is in the range of 80% to 90%.