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Photodynamic Therapy's Efficacy Draws Strong Testimonials


 

LOS CABOS, MEXICO — Advances in photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA) have led dermatologists to increasingly extol its virtues as a practical, versatile, and highly effective therapy for actinic keratoses, nonmelanoma skin cancer, acne, and photorejuvenation.

For example, at the annual meeting of the Noah Worcester Dermatological Society, several dermatologists described ALA-PDT with a degree of enthusiasm pointedly absent from presentations concerning many new lasers, skin smoothers, and nonablative, all-purpose devices.

"[It has] … changed the way I practice," Dr. C. William Hanke said at the meeting.

Dr. Hanke said he recalled hearing about ALA-PDT at an American Academy of Dermatology meeting 5 years ago. His impression of the therapy then was "how terrible it was. There was a lot of hand-holding … because the patient needed it."

Still, it seemed to work pretty well in eradicating actinic keratoses (AKs), and a 2003 study showed that it had the potential to be equal to 5-fluorouracil in efficacy and was preferred by most patients, despite the painful recovery required after a 14− to 18-hour ALA incubation period and subsequent exposure to a specialized light source (J. Drugs Dermatol. 2003;2:629–35).

Since then, ALA-PDT has changed dramatically in the following ways:

Short-contact ALA-PDT is now standard. ALA remains on the skin just 15–60 minutes, profoundly affecting the side-effect profile and reducing pain. Instead of enduring a week of raw skin, erosions, and inflammation, most patients today note only minor stinging, erythema, and scaling that resolve within a few days. Many studies show that short-contact ALA-PDT does not reduce its effectiveness.

Numerous light sources are being used. Although blue light emits a wavelength (405–420 nm) that conforms precisely to the absorption peak for ALA (marketed as the Levulan Kerastick by DUSA Pharmaceuticals Inc.), intense pulsed light (IPL), pulsed dye lasers, and other light sources also are proving effective.

The versatility of ALA-PDT is expanding. Approved for nonhyperkeratotic AKs of the face and scalp, it also is being used on the trunk and extremities for AKs, nonmelanoma skin cancer, pigmented lesions, rosacea, and, especially, acne.

Competition is on the horizon. An American launch is imminent for the photosensitizer methyl aminolevulinate, marketed as Metvix by the Norwegian company PhotoCure ASA. Widely used in Europe, Metvix is incubated for 3 hours under occlusion and activated by red light (630–660 nm) from a diode laser. Besides treating AKs and nonmelanoma skin cancer, the system is used to treat psoriasis.

Dr. Neil S. Sadick voiced a common complaint when he noted that nonablative therapies have now been used for 5 years to treat everything from rosacea to scars, "and we're still not sure [they're] effective or worth it."

In contrast, he said that IPL, which targets chromophores, has become a mainstay in his practice, "providing the greatest amount of clinical satisfaction, consistently, for [the] patients."

When he's treating more than telangiectasias, age spots, and minimal actinic damage, Dr. Sadick said he relies on ALA to amplify the impact of IPL.

"I can decrease five treatments to two [or] three treatments with IPL … for significant actinic damage. It's not nonablative; I would call it microablative," said Dr. Sadick, who practices in New York City and Great Neck, N.Y.

Dr. Mitchel P. Goldman said short-contact ALA-PDT using IPL is "incredibly impressive" for acne and a convenient and "very mildly painful" option for patients with actinic keratoses, telangiectasias, and skin texture problems. He even used the modality to treat his own facial squamous cell carcinoma.

He uses a pulsed dye laser rather than IPL on hair-bearing areas because IPL can remove hair.

Like Dr. Sadick, Dr. Goldman uses ALA-PDT to "boost" the effectiveness of IPL, reducing the number of treatments required.

After one or two treatments of ALA-PDT with IPL for actinic keratoses, "I think that's when you need to biopsy," said Dr. Goldman, who is in private practice in La Jolla, Calif.

Dr. Hanke, director of a dermatologic surgery practice in Carmel, Ind., says that ALA-PDT has become ever more useful in his practice over time, for cosmetic as well as medical dermatology.

If a patient's goal is to have smoother, clearer skin, with less blotchiness and redness, "we can do that," he said.

There are conditions, such as wrinkles, that do not respond well to ALA-PDT, the speakers agreed. In addition, Dr. Hanke said he was unimpressed by its results in a renal transplant patient with extreme sun damage that included a history of skin cancers and many keratoses.

It also doesn't work for disseminated superficial actinic porokeratosis or granulomatous rosacea, he concluded.

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