KISSIMMEE, FLA. – Reflective confocal microscopic imaging successfully guided carbon dioxide laser ablation of basal cell carcinomas, and imaging results fully matched those from Mohs histology, a small study found.
“Our results suggest that reflective confocal microscopy can accurately guide carbon dioxide laser ablation of superficial and early nodular basal cell carcinomas,” said Dr. Brian Hibler of Memorial Sloan Kettering Cancer Center in New York. The technique provides a real-time, noninvasive way to delineate the tumor area before ablation and to check for residual tumor between passes with the laser, he said at the annual meeting of the American Society for Laser Medicine and surgery.
While conventional and Mohs microscopic surgeries remain the gold standard for removing basal carcinomas (BCC), surgery is not an option for some patients because of tumor location, comorbidities, or personal preferences, Dr. Hibler noted. Past studies have reported good clinical and cosmetic outcomes with laser ablation of BCCs, but use of the modality has been limited because there was no way to assess response without excision or biopsies. Reflective confocal microscopy (RCM) uses a low-powered laser system that provides cellular-level imaging and can distinguish BCCs, he said.
Dr. Hibler and his colleagues performed baseline RCM of eight BCCs (three on the trunk, three on the extremities, and two on the head and neck) from seven patients aged 29-83 years. Two patients were men and five were women. The patients then underwent carbon dioxide laser ablation with a wavelength of 10,600 nm, pulse duration of 750 microseconds, and fluence of 7.5 J/cm2, using a square pattern and density of 30%. If RCM revealed residual BCC, the researchers repeated the process up to two more times, for a maximum of three passes. They then removed the entire lesion using Mohs micrographic surgery, performing vertical histologic sectioning of the tissue.
Reflective confocal microscopy generated reliable cellular-level images in real time on the tumor surface and up to 150 mcm deep, Dr. Hibler reported. Tissue from BCCs appears as dense nodular areas with adjacent spaces and red blood cell trafficking, he noted. Microscopy results were consistent with Mohs histology findings in all eight cases, including six in which the tumor was completely removed and two with residual tumor. One of these two cases was the only infiltrative BCC in the series, while the other might have been tissue artifact, Dr. Hibler said.
Patients experienced no adverse effects from the interventions, Dr. Hibler reported. “Future studies are planned are planned without Mohs, so we can use reflective confocal microscopy to longitudinally monitor for recurrence,” he added.
The study won an award at the meeting.
Dr. Hibler reported no funding sources and made no disclosures.