Squamous and basal cell carcinomas of the skin (also referred to as Non-Melanomatous Skin Carcinoma, NMSC) are the most common malignancies in the United States, caused almost exclusively by the UV rays related to Sun exposure. They are typically managed with surgical excision, which occasionally requires a Mohs’ procedure to confirm negative margins. Radiation therapy is a less convenient form of treatment, however it normally achieves the same probability of cure as surgery.
Radiation therapy is commonly used as an alternative to surgery. In these settings, the cure with radiation is still usually very likely. Several examples include;
- a skin cancer which has aggressive characteristics such as local or regional recurrence after surgery.
- a skin cancer that is too large or in a location that will require skin grafting or disfigurement, resulting in a poor appearance following surgery.
- a patient whose health is not sufficient to undergo surgery. The surgeon may be concerned the patients wound will not heal or may get infected.
The type and technique of radiation therapy used to treat skin cancer depends upon the size and location of the lesion. The treatments are non-invasive and painless with little risk of infection. Cure rates are typically in the range of 90 %.
If squamous or basal cell skin cancers are superficial and less than 4 cm in size then electronic brachytherapy can be used to apply a very superficial dose of radiation. This type of radiation can be administered in 8 treatments, 2 treatments per week for four weeks, each lasting approximately 10 minutes. These treatments can be administered within a physicians or dermatologist office for the patients convenience.
Fortunately, both squamous and basal cell carcinomas larger than 4 cm, and less common skin cancers including Melanoma or Merkel cell skin cancers, can also be effectively treated with electron beam radiation therapy. These treatments are administered directly to the skin cancer using a linear accelerator in a radiation therapy department over 3 to 7 weeks, depending on the size and location of the cancer.
Occasionally, skin cancers can spread to nearby lymph nodes. Examples could include a squamous cell carcinoma of the scalp or face that has spread to the lymph nodes of the neck. Treatment could require a CT scan and either 3D or IMRT treatment planning, to safely and effectively treat the cancer, administered daily over 6 to 7 weeks. In this setting, patients may also benefit from the addition of concurrent chemotherapy.
Fortunately, most skin carcinomas respond very well to radiation and generally patients experience a high cure rate with good to excellent long-term cosmetic results.