Radiation for Skin Cancer
Posted on: March 8, 2018
Mr. S is a 70 year old man who noticed a lump on the left side of his nose several months ago. The lump quickly grew, and a biopsy showed squamous cell carcinoma (SCC), a type of skin cancer. He was treated for a squamous cell carcinoma on his arm several years ago with Mohs surgery, a procedure in which a dermatologist shaves off layers of skin to remove the cancer. He asked me, “I hated going under the knife for my skin cancer. Is there another option?”
SCC of the skin is one of the most common malignancies diagnosed in the US, with over 700,000 new cases each year. It occurs most frequently on sun-exposed skin in fair-skinned individuals, though may also develop in people with darker skin. SCC of the skin is associated with exposure to ultraviolet light from the sun (UVA and UVB), and occurs more often in people over 45 years old. Patients who have undergone organ transplantation and require chronic immunosuppression are also at greater risk of developing skin cancer. This type of cancer can take many forms, including flat red spots, painless bumps, or scaly patches on the skin. A doctor needs to biopsy the skin to confirm the diagnosis of cancer.
Over 90% of skin SCC are cured with local therapy alone, usually surgical excision like Mohs. An advantage of Mohs microsurgery is that the surgeon can look at the cells as they are being removed, to ensure that all of the cancer has been fully excised. Low-risk SCC may also be treated with freezing (cryotherapy) or a topical cream, such as Aldara. Some patients may need radiation after surgical excision, if the cancer cells have aggressive features, such as invasion into the local nerves, or if the cancer could not be fully excised.
Radiation therapy alone is another non-invasive way to treat skin cancers. High-energy X-rays are directed at the tumor to kill the cancer cells. Using radiation to treat skin cancer is a reasonable option for patients who cannot tolerate surgery or those who have problems with wound-healing after surgery. It is also used for skin cancers in sensitive regions where surgery could be potentially disfiguring, such as at the tip of the nose or the ears. The cure rate for early stage skin cancer is over 95% with radiation therapy alone.
Radiation therapy can be delivered in several different ways, including superficial electron radiation or electronic brachytherapy. Electronic brachytherapy using the Xoft system uses a miniaturized X-ray source to deliver radiation to the skin cancer. The treatment is given twice a week for four weeks, and each treatment lasts about five minutes. The side effects can include skin irritation and redness, hair loss in the treatment area, and possible blistering and peeling of the skin. The treatment is not ideal for all skin cancers, but may be a convenient option for some patients.
Dr. Chung is a board certified radiation oncologist with Diablo Valley Oncology & Hematology Medical Group in Pleasant Hill. She has a special interest in treating skin and breast cancer. Dr. Chung sees patients in Pleasant Hill and Berkeley. For more information call: 925-825-8878.