By Ed Susman
DENVER –Focal non-melanoma skin cancers can be destroyed without surgery using electronic brachytherapy, according to research presented at the 72nd annual meeting of the American Academy of Dermatology.
Of 277 lesions treated with the new modality, no recurrences have occurred during follow-up that ranged from 1 month post treatment to 51 months, says Ajay Bhatnagar, MD, a private-practice radiation oncologist in Casa Grande, Ariz, and an adjunct assistant professor of radiation oncology at the University of Pittsburgh.
“Our mean follow-up is 13 months,” Bhatnagar says. His group treated 160 basal cell carcinomas; 110 squamous cell carcinomas; two Merkel cell carcinomas, and three lymphomas in 187 patients.
“Electronic brachytherapy provides a convenient nonsurgical treatment option for non-melanoma skin cancer patients,” he says. “We have had no recurrences to date, but more follow-up is being collected. Toxicities were acceptable.”
A rash common to that seen with conventional radiation techniques was experienced by 84% of the patients at the end of treatment, he says. By 3 months, the rash lingered in around 18% of 145 lesions; by the end of 3 years, there was no clinically visible rash in 28 treated lesions. Overall, Bhatnagar says that 84% of the patients experienced Grade1 dermatitis and 16% of patients experienced Grade 2 dermatitis.
The only grade 3 severe adverse event was a non-healing foot ulcer that eventually required hyperbaric oxygen treatment to resolve.
Good-to-excellent cosmesis by the 12-month post-treatment visit. One patient was judged to have fair cosmesis at 6 months; one patient was judged to have poor cosmesis at 3 months and 6 months.
Bhatnagar uses a miniature, finger-tip sized, electronic high dose radiation, low energy x-ray tube with produces x-rays of 50 keV (milli-electronvolt) maximum energy. Patients receive 40 Gray doses in eight fractions. The applicator is placed within millimeters of the lesion, providing accurate dosing. The prescription depth is 3 mm with a 5-mm-wide margin.
During the procedure, a thermoplastic mask is placed on the patient with a cutout for the area to be treated. Then, the surface applicator is placed in contact with the skin, and patient shielding is put in place. The electronic brachytherapy device and controller is stationed a couple of feet from the patient. No shielding for the clinician is required, Bhatnagar says.
In the study, the mean age of the patients was 74 years, ranging from 48 years to 98 years of age. He says 63% of the cohort is men and 97% of the patients are non-Hispanic Caucasians. There were 74 lesions located on the nose that were treated (26.7%), with 31.8% of the lesions located on the face—forehead, temple, eyelid, glabella, sideburn, lip, cheek, and chin; 12.3% of the treatments were to the ears; 9% to the scalp; 15.9% to the extremities and 4.3% were on the torso.
Twenty of the lesions were recurrences from previous therapies, Bhatnagar says. About 94% of the lesions treated were 2 centimeters in diameter or less. The device is limited in treating lesions greater than 5 cm. Only one lesion between 4 cm and 5 cm was treated in his series.