Photodynamic therapy systems: Doctors face off on pros, cons as skin cancer treatment

May 1, 2009

The use of photodynamic therapy is increasing, and yet the modality hasn't made much headway in the United States as a treatment for nonmelanoma skin cancers. Two dermatologists face off on its prospects for skin cancer treatment in the United States.

Key Points

The first to receive approval was DUSA Pharmaceutical's combination of Levulan, an aminolevulinic acid (ALA) photosensitizer with BLU-U as light source.

More recently, the FDA approved a system developed by the Norwegian company PhotoCure ASA that is widely available in Europe. It combines Metvixia, a methyl ester of aminolevulinic acid (MAL), with Aktilite, a red light source. The system has been commercially available in the United States through Galderma SA since January 2009.

Efficacy

There is no question that photodynamic therapy works, Dr. Gold says.

"The European literature for Medvixia has documented the benefits of what it can do in treating nonmelanoma skin cancer. Hundreds of patients have been followed for at least five years. The results are as good as, if not better than, surgery and cryotherapy," he says.

'Politicking'

Importantly, PhotoCure initially sought FDA approval for PDT treatment of superficial and nodular basal cell carcinoma, but was nixed by the FDA's Dermatologic and Ophthalmic Drugs Advisory Panel, which called MAL-PDT "a niche product."

Since efficacy had already been established in Europe, Dr. Gold questions whether the decision was "politicking by surgeons who prefer to cut cancer out."

Whatever the FDA's reasons, he says that most U.S. dermatologists use PDT for treatment of actinic keratosis (AK) and signs of photodamage. In contrast, European dermatologists use PDT for treatment of nonmelanoma skin cancer and, occasionally, for AK.

Dr. Gold is concerned that financial variables will factor too highly in the decision-making process.

"PDT has a role in treating skin cancer, especially when you don't want to cut off half the ear or nose. But here's a rhetorical question: If you get $1,000 for cutting and zero for using a topical, what are you going to do? I use PDT, even though I lose money every time," he says.

Chemoprevention

"People who have organ transplants develop many squamous cell carcinomas (SCCs). There is no question that treating them with Levulan and blue light reduces the number of SCCs they get each month or year," he says.

He treats the patient's entire face, eliminating existing AKs and prophylactically reducing the rate of recurrence.

"I'm fortunate to be able to travel a lot and consult with doctors all over the world. I see the results my European colleagues are getting with PDT.

"It will take years, hundreds of patients and millions of dollars to get approval in the U.S. for skin cancer prevention or treatment. I'm not sure Galderma or DUSA will do it. If and until that happens, only forward-thinking doctors will use PDT," Dr. Gold says.