April 2006
Dear Paula,
I am a medical doctor (a pathologist) and I enjoy reading your well-researched and informative articles. A nice change from the rubbish that is usually meted out to the public!

I have a lot of actinic keratosis on my face, and my dermatologist has recommended Levulan and BLU-U light therapy (activated photo facials). He stated that two treatments would be fine and I would just suffer some “sunburn” effects for the first week. As well as getting rid of the keratosis without scarring, this treatment supposedly smoothes the skin and makes it look better. It is still relatively new, and I am concerned that the use of light to activate a cream which is known to be toxic to cells may be a risk for skin cancer down the line. I would be grateful for any information you can give me on this.

Margaret, via email

Dear Margaret,

As you may know, actinic keratosis (AK) is a very common skin problem, especially for people over 40. It can eventually turn into invasive squamous cell carcinoma of the skin. These precancerous lesions are caused by sun exposure and appear on the skin as uneven brown patches that can become crusty and sometimes itch. Getting diagnosed and finding a treatment is essential.

Your physician is recommending a treatment known as Photodynamic therapy (PDT) in conjunction with topical application of 20% 5-aminolevulinic acid (ALA, under the tradename Levulan). The ALA is activated with a red or blue LED panel (light-emitting diode) or IPL (intense pulsed light), which explains the name. The IPL is not related to UV light from the sun.

Photodynamic therapy really isn’t all that new. In 1999, the FDA cleared Levulan Kerastick for the treatment of AKs on the head and scalp. A year later, the BLU-U, Blue Light Photodynamic Therapy Illuminator, was also FDA approved for the treatment of AKs.

Photodynamic therapy works because the ALA is a photosensitizing chemical that is applied to a specific AK lesion. When this is followed by exposure to visible light, it causes the precancerous cells in the specific area to die off. Interestingly enough, ALA in and of itself is not a photosensitizer, but rather it causes the formation of a natural photosensitizer in the skin. There is definitely research showing that it is effective and safe. Given the short period of treatment, it is believed that the risk of UV damage is minimal, and that the risk of generating more cancer-producing cells is unlikely, given the short time the ALA remains in the skin (about six weeks). In fact, ALA stays longer in cancer cells than in normal cells. Also, ALA doesn’t cause a cytotoxic response in and of itself but only in combination with a light source. Other advantages of PDT are that it causes minimal damage to healthy tissue, and that the light that is used can’t pass through more than about one-eighth of an inch of skin. If anything, as your doctor mentioned, the procedure may even improve skin conditions.

Whether or not photodynamic therapy can also workto minimize or reduce wrinkles is far less well researched, and most of the research I’ve seen about its effects on wrinkles comes from physicians who were paid by the company that makes the light-emitting machines and the ALA. Overall, the efficacy of this process can’t be ignored, especially when compared with other options. For example, AKs can be treated by curettage, which involves scraping the lesion off with a heat-producing needle, or they can also be shaved off with a scalpel. Cryosurgery freezes the lesions off through application of liquid nitrogen. All of these methods have problems, some with short-term results or skin discoloration, others with scarring.

It’s important to point out that depending on the extent of the AKs on your skin, they can resolve with adequate sun protection and avoiding more exposure, but that is often easier said than done (Sources: International Journal for Cancer Research and Treatment, April 2004, pages 407–411; Journal of Dermatological Treatment, March 1, 2002, pages 19–23; Journal of Photochemistry and Photobiology, May 2001, pages 656–669; Journal of Cosmetic Laser Therapy, March 2005, pages 21–24; Journal of Drugs in Dermatology, January–February 2004; Facial and Plastic Surgery, May 2005, pages 110–116; Cancer Information Network, www.ontumor.com/cancer/photodynamic.asp; and American Osteopathic College of Dermatology, www.aocd.org).