The trial The trial was designed and is being conducted by Kristen M. Kelly, M.D., associate clinical professor of dermatology, and was presented at the annual meeting of the American Society for Laser Medicine and Surgery by dermatology resident Peyman Ghasri, M.D. It enrolled 10 patients with one or more hypertrophic or keloid scars. In each subject, one-third of the target lesion(s) received a single radiofrequency treatment with the ThermaCool TC™ system (Thermage, Hayward, Calif.), one-third was treated at two sessions, and the other portion served as an untreated control.
Data from clinical evaluations of eight patients who completed two treatments and were seen at least four weeks after the second treatment showed two subjects reported a slight decrease in symptoms at the treated sites. However, the procedure had no positive or negative effects on measures of scar appearance compared both to baseline and the control site. Results from evaluation of tissue specimens obtained from biopsies performed in two patients showed the radiofrequency treatment was associated with changes in procollagen 1 and procollagen 3 production as well as in collagen configuration and density."We will continue to follow these patients at 12 and 24 weeks after the second treatment to fully assess any potential clinical benefit from the radiofrequency procedure and to further evaluate the histological changes. The fact that we do see some changes in collagen is interesting, and depending on our future findings, perhaps we might consider investigating radiofrequency in combination with other modalities, such as intralesional steroids, to see if a dual approach might provide an enhanced response," Dr. Kelly says.
The researchers were interested in evaluating radiofrequency treatment for hypertrophic and keloid scars knowing that those lesions are characterized by alterations in the ratio of collagen 1 to collagen 3, and that the radiofrequency procedure causes collagen reorganization.
"Radiofrequency treatment is associated with initial collagen damage, but that is followed by reorganization, and we hypothesized that reorganization to a more natural state might lead to some improvements in scar appearance," Dr. Kelly says.
The eight patients included in the analysis were equally divided by gender and ranged in age from 20 years to 74 years (mean 39). All scars were nonfacial, but locations included the trunk and extremities. The scars were all mature and at least a few years old, but some were very old (up to 50 years).
The radiofrequency treatment was performed under topical anesthesia (EMLA Cream applied for approximately 30 minutes pretreatment) with a setting ranging from x2 to x6 (average x4) using a 1.5 cm2 square tip. The second treatment was performed four weeks after the first.
The procedures were well-tolerated and did not result in any adverse effects.
Two investigators rated changes in scar appearance using various scales to characterize pigmentation, vascularity, pliability and height. In addition, patients were asked to rate symptoms such as itching and burning, on a scale of 0 (none) to 3 (severe).
The biopsy specimens were examined using hematoxylin and eosin (H&E), immunohistochemistry stains for procollagen 1 and 3, and with multiphoton microscopy to evaluate fibrils. Only the H&E evaluation showed no changes.
Results of the immunohistochemistry studies demonstrated increases in the ratio of activated fibroblasts for procollagen 1 and procollagen 3 production after one treatment in both patients, but the magnitude of those responses differed. One patient exhibited a marked increase in activated fibroblasts for procollagen 3 and a slight increase in procollagen 1, while the results in the second patient showed moderate increases for both types of procollagen. Once again; however, the increase in procollagen 3 was greater than that of procollagen 1. After two radiofrequency procedures, there was little difference between the treated and control sites for either type of procollagen in either patient.
The multiphoton microscopy studies also showed distinct differences in collagen fibrils between the control and treated sites, as well as between patients. The inter-patient differences noted in these histological evaluations are interesting because the two biopsied scars had different characteristics, Dr. Kelly says.