Lasers offer ever-expanding indications

October 1, 2007

One expert reviews the latest studies on various laser and light technologies and reports on their ever-expanding indications in dermatology.

Keypoints:

New York - Recent studies of cosmetic lasers demonstrate the efficacy of these tools for a variety of indications, an expert says.

Treatment for hemangiomas

Leonard J. Bernstein, M.D., Laser & Skin Surgery Center of New York and assistant clinical professor of dermatology, Weill Medical College, Cornell University, reported on a study that assessed the efficacy and complications of early therapy of hemangiomas in children with a traditional short-pulsed pulsed dye laser (PDL) versus a long-pulsed PDL. The study involved 52 children with superficial hemangiomas or hemangiomas in the early proliferative growth phase.

The use of multi-pass treatments has been thought to increase efficacy, but the results reported are conflicting, he says. Until recently, physicians avoided the multi-pass treatments due to the perceived increased risk of side effects.

Other research

In another study including 16 patients who had test spots for purpuric thresholds on the buttocks, researchers analyzed the effects of PDL double-pass treatment intervals versus single-pass treatment intervals on the depth of vessel coagulation.

Each patient had exposure to single-pulse and double-pass intervals 1, 5, 10, 30 and 60 seconds, as well as five and 30 minutes at both threshold fluences and a fluence well above threshold.

"The results of this study showed that contrary to the expectation that shorter-pulse intervals would lead to greater tissue injury, at fluences above threshold purpura, the opposite is seen. At threshold, it is also observed that while increasing pulse intervals up to 60 seconds, there is a gradual increase in tissue injury. However, between one and five minutes, there is a return to a state similar to a single-pulse depth of injury. This would suggest a transient biological response is occurring," Dr. Bernstein says.

Photodynamic therapy

According to Dr. Bernstein, multiple studies of the effectiveness of PDT in the treatment of basal cell carcinomas have shown a highly variable success rate with recurrences ranging from 10 percent to more than 21 percent.

One recent study evaluated the effectiveness of fractionated illumination PDT for superficial BCCs with very specific fluences for each fraction of illumination compared to traditional PDT protocols.

Of the 155 patients included, 100 patients and 55 patients received single and double illumination, respectively. Topical 20 percent ALA ointment mixed with lidocaine was applied under photo-occlusion for four hours before any illumination, and all patients were treated with red light sources at a constant fluence rate of 50 mW/cm2 .

Results at 12 months demonstrated that fractional illumination PDT has a greater cure rate than single illumination PDT in the treatment of superficial BCCs.

"The time interval of the fractionated illumination is critical, and it appears that the interval should be at least two hours to allow the further accumulation of PPIX in these cells," Dr. Bernstein says.

Ablative lasers

One recent study compared the long-term follow-up of topical 5-fluorouracil versus laser resurfacing in the treatment of widespread actinic keratoses, in regard to efficacy, recurrence rates and side effects.

Of the 55 patients included, 28 patients were treated with Er:YAG laser combined with CO2 (Derma-K), and 27 patients received 5-FU treatment for four weeks BID. At four weeks, if clinically desired levels of crusting, scaling, erosion or inflammation were achieved, the treatment was stopped. If these were not achieved, treatment was continued for an additional one to three weeks.