Radiation therapy has been used for the treatment of skin cancers since the early 1900’s and continues to be one of the best therapies available. Significant advances have revolutionized radiation therapy technologies, increasing treatment precision and reducing side effects.
Although surgery is a very effective treatment, there are occasional risks:
- impaired wound healing (particularly in those with diabetes, the elderly, peripheral vascular disease, smokers)
- post-operative bleeding
- post-operative wound infections
- surgical scars
- functional and/or cosmetic deformities (in some circumstances skin grafts/flaps may be required to cover the surgical defect)
How effective is radiation therapy?
The images below demonstrate the excellent results that are typical after radiation treatment.
- Patient 1: Face/ear invasive squamous cell carcinoma treated with radiation therapy. Had surgery been the treatment offered, this patient would likely have required extensive surgery and a skin graft or flap to cover the surgical defect. (Left image: before radiation therapy; Right image: after radiation therapy)
- Patient 2: Eyelid skin cancer treated with radiation therapy. Surgery would have led to a cosmetic/functional defect in the lower eyelid. (Left image: before radiation therapy; Right image: after radiation therapy)
- Patient 3: Cheek skin cancer treated with radiation therapy. (Left image: before radiation therapy; Right image: after radiation therapy)
There are a variety of risk factors that may reduce the efficacy of radiation therapy (i.e. larger tumor size, aggressive skin cancer subtype, recurrent skin cancers, invasion into nerves, vessels or underlying muscle or bone). Based on these and other factors, appropriate treatment recommendations will be made.
How is radiation therapy administered?
There are a variety of radiation therapy technologies that may be used to precisely deliver a superficial form of radiation (i.e. electrons, x-rays, gamma-rays) that penetrates only a short distance below the skin surface.
We often include a small (i.e. 5-10 mm) margin of skin around the cancer within the radiation treatment area to make sure that we don’t inadvertently miss any tumor cells that may be growing microscopically into the adjacent tissues.
The following modalities are commonly used:
- External beam radiation therapy (i.e. superficial x-rays, electron beam therapy)
- Brachytherapy (i.e. read about “HDR brachytherapy”, below)
What is the length of the treatment course?
Treatments typically take less than 5 minutes to deliver, each day. Depending on different factors, your physician will recommend the appropriate treatment course (duration range: 2-7 weeks). Most treatments are delivered 5-days per week (monday-friday), although some treatment courses may only require 2-3 days per week.
One of the more convenient treatment options is a twice-a-week treatment (5-minutes each session) for 3-weeks, using a technology called “high-dose rate brachytherapy” (HDR). The ideal candidate for HDR treatment is anyone with a basal or squamous cell skin cancer that less than 1-inch (2.5 cm) in diameter and less than 5 mm in depth. The image below demonstrates an example of how the HDR treatment applicator, which holds a small radioactive seed, is gently placed over the lesion to be treated (Below: basal cell cancer on the right-side of the nose).
The HDR applicator is then connected to a robotic device (called an “afterloader”) by a catheter. The radioactive seed is contained inside the afterloader robot, remains there until the treatment. During the treatment, the robot sends the radioactive seed through the catheter and into the HDR applicator. The seed then retracts back into the robot when the treatment is done (treatment time: approximately 5-minutes.)
Who is a candidate for radiation therapy?
- Anyone with a basal or squamous cell skin cancer who has not been previously treated with radiation to the same area as the new cancer is a good candidate, or
- Anyone who does not want surgery, or
- Anyone who has healing difficulties (i.e. diabetics, elderly) or bleeding problems (including those who need to remain on blood thinning medications), or
- Anyone who has multiple skin cancers or larger skin cancers in one or more regions on the body (i.e. scalp, face, extremities, trunk, torso), or
- Anyone who has been told that surgical removal of the cancer may require plastic surgery (i.e. skin graft, flap) to cover the surgical defect,
- Anyone with skin cancers in cosmetically and functionally challenging areas (i.e. eyelids, nose, ears, lips, hands)
- Other skin cancers that can also be treated with radiation include: melanoma (reserved for patients who are too ill or refuse surgery), Merkel cell carcinoma, sweat gland tumors
What are the side effects of this treatment?
You will not feel anything during your radiation treatments- they are painless. For the first 1-2 weeks of treatment, most patients do not notice any symptoms or side effects.
After 2-3 weeks, the most common side effects are skin redness, peeling and mild-to-moderate skin sensitivity in the area of the cancer. In the vast majority of patients, these symptoms will resolve within a few weeks after the treatment course is over. (Top picture: one week after completing treatment for a basal cell cancer of the left-side of the nose, Bottom picture: four weeks after completing treatment)
Months-to-years after the treatment, the radiated skin may develop a slightly lighter or darker appearance, although most patients have no obvious skin coloration changes. Additionally, the radiated skin may become slightly thicker or firmer over time.
Although this is a very rare risk, cancer can develop in the radiated tissues years after treatment. The risk is 1 in 1,000 people who receive radiation.
Radiation therapy is an excellent treatment for the two most common skin cancers (basal cell and squamous cell carcinomas), however it may or may not be appropriate for you. It is important to discuss this with your physicians.
Start by asking your dermatologist if they believe that radiation therapy is a reasonable option for you, as there are many treatment options available that I did not discuss in the blog post.
Learn more about skin cancers here. (American Academy of Dermatology)