Superficial radiation therapy ripe for resurgence

Miami Beach, Fla. - Newer superficial radiation therapy (SRT) equipment can help dermatologists battle the growing number of nonmelanoma skin cancers (NMSCs) safely, effectively and cost-effectively, an expert says.

Dermatologists basically invented SRT, says Mark S. Nestor, M.D., Ph.D., voluntary associate professor, department of dermatology and cutaneous surgery, University of Miami Miller School of Medicine. At the peak of SRT’s popularity, he adds, more than half of dermatologists offered this treatment in their offices. Now, he says, only 300 to 400 dermatologists in the United States use this modality regularly, plus many more who use it sporadically.

By the early 1980s, Dr. Nestor says, SRT had fallen out of favor because manufacturers had not introduced any significant innovations, “and people’s equipment was falling apart. But now, with the severe increase of skin cancer incidence in older patients, this may be the ideal treatment for many patients.”

Electron-beam radiation, used primarily by radiation oncologists, delivers a more powerful treatment than the low-energy X-rays used for SRT, he says. Therefore, electron-beam radiation is possibly appropriate for some very deep skin cancers.

“But the downside is patients get many more side effects due to radiation exposure on normal tissue,” Dr. Nestor says.

SRT a viable option

Conversely, he says many studies show that for appropriately selected skin cancers, SRT provides higher cure rates than electron-beam radiation, with fewer side effects. In one review, local tumor control rates for basal cell carcinomas (BCCs) measuring 1.1 cm to 5 cm for SRT and electron-beam radiation were 93 and 73 percent, respectively (Lovett RD, Perez CA, Shapiro SJ, Garcia DM. Int J Radiat Oncol Biol Phys. 1990;19(2):235-242).

A recent retrospective analysis of 1,715 histologically confirmed primary cutaneous NMSCs - including 712 BCCs and 994 SCCs - showed that SRT is a viable nonsurgical option for appropriately selected tumors (Cognetta AB, Howard BM, Heaton HP, et al. J Am Acad Dermatol. 2012;67(6):1235-1241). Overall two- and five-year recurrence rates were 1.9 and 5.0 percent, respectively.

Performing brachytherapy properly requires isotopes, Dr. Nestor says. As such, “This whole new idea of electronic brachytherapy isn’t really brachytherapy. At this point, I believe it’s more of a gimmick” that raises concerns including the potential for improper use of isotope-radiation insurance codes in billing these procedures.

SRT, on the other hand, delivers accuracy and safety with greater simplicity, thanks to new computerized equipment, he says. Recent innovations in also include a better understanding of fractionation, the science of dividing radiation doses for maximum safety and efficacy, he adds.

“If we divide up the treatments appropriately, we get high cure rates and low rates of side effects. The way we’ve learned to do that, especially regarding side effects, is dividing the treatments into small pieces,” Dr. Nestor says.

Although dosing requirements differ depending on factors, including tumor size and location, a typical dose is around 4,000 to 5,000 centigrays (cGy), divided evenly between 12 to 17 treatments, he says. Patients typically undergo two to five treatments weekly. Dr. Nestor’s practice has treated more than 300 NMSCs using SRT in the past two years and has seen excellent clinical and cosmetic results.

“The actual treatment itself only takes a couple minutes, although it takes time to set the patient up properly and safely,” Dr. Nestor says.

After all of the treatments, he says, patients’ skin generally gets slightly red and scaly, but these mild side effects resolve within a short period of time.

Tumor selection

Regarding patient and tumor selection, he says, “SRT is not for all patients and all skin cancers. It’s mostly for older patients with NMSC in hard-to-heal locations such as the legs or scalp, or in areas where patients don’t want surgery, such as the nose.”

Other indications for SRT include recurrent keloids, he says.

“Data show that with SRT, keloid recurrence he can be reduced from what is normally about 70 percent or 80 percent to 10 percent or 15 percent after two to three sessions,” he says.

Many dermatologists seem open to revisiting SRT, Dr. Nestor says, because they have extensive experience with it. A handful of residency programs teach the technique, he adds, and continuing medical education and certification opportunities at meetings including the 2014 American Academy of Dermatology annual meeting are growing. Current-generation SRT equipment sells for around $200,000, which can be comparable to lasers and other dermatologic devices, he says.

 “In the future, due to the rising tide of skin cancers and the advent of new technologies, use of SRT in dermatologists’ practices is going to increase because it's the appropriate thing to do for many patients,” Dr. Nestor says.

Disclosures: Dr. Nestor is a consultant and advisory board member for Sensus Healthcare and has received research grants from the company.