Light vs. Freezing for Actinic Keratosis

Photodynamic therapy for actinic keratosis had better chance of complete lesion clearance than cryotherapy

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Spending lots of time under the sun's harmful rays can cause skin patches called actinic keratoses (AKs). In some cases, these scaly, rough patches can turn into skin cancer, so doctors usually recommend removing them. But what's the best way to remove them?

A recent study compared two methods for removing AKs. The first is called photodynamic therapy (PDT) and uses special lights to activate medications on the patient's skin. The second, called cryotherapy, involves freezing the skin patch and surgically removing it.

This study revealed that, compared to those treated with cryotherapy, patients treated with PDT had a better chance of being completely clear of their AK three months after treatment.

"See a dermatologist if you develop scaly patches on your skin."

From their analysis of four past randomized trials on PDT, Gayatri Patel, MD, MPH, of the University of California Davis Medical Center, and colleagues concluded, "For thin AKs on the face or scalp, PDT has a 14 percent better chance of lesion clearance compared with cryosurgery."

Coyle S. Connolly, DO, Board Certified Dermatologist and President of Connolly Dermatology in New Jersey, told dailyRx News that both treatments have their merits in his practice.

"For thicker, resistant actinic keratosis, cryosurgery is the gold standard. The dermatologist is able to identify the specific lesion and freeze the area with pinpoint precision," said Dr. Connolly, who was not involved in this study.

"PDT is an alternative for patients with multiple, widespread lesions that cannot tolerate cryosurgery," he said.

The US Food and Drug Administration (FDA) approved PDT for the treatment of AKs 15 years ago.

In a commentary on this recent study, Harvey Lui, MD, FRCPC, of the University of British Columbia, wrote that PDT is now generally considered best for patients who have multiple or larger patches.

Dr. Lui wrote that PDT has some limitations compared to other treatments. For one, PDT is more expensive because of the equipment and doctor's time that it requires. Another limitation is that PDT can cause localized pain, leading some patients to never undergo a second treatment.

According to Dr. Lui, "daylight" PDT, which uses sunlight rather than specialized lamps, could make the treatment less expensive. Also, patients have reported less pain when using outdoor light to activate the medication than when using indoor lamps.

"Cryosurgery is uncomfortable but tolerable for patients and can sometimes leave light spots on the skin. PDT therapy may cause discomfort but rarely results in light spots," Dr. Connolly explained.

"Keep in mind that not all dermatologists utilize PDT machines in their practices. Other options for AK treatment include topical creams, such as imiquimod and fluorouracil, depending the patient's age and number, location and thickness of lesions," he said.

"The best advice is for a patient to discuss all treatment options and side effects with their dermatologist," he recommended.

The study by Dr. Patel and team, as well as the related commentary by Dr. Lui, was published in JAMA Dermatology.

Dr. Lui reported several potential conflicts of interest. He has served as a researcher and consultant for Galderma and LEO Pharma Inc. in regard to actinic keratosis; has served on advisory boards for Janssen, Novartis and Valeant; has equity interest in RepliCel Life Sciences Inc., Lumen Health Technologies and Verisante Technology; and receives dermatology textbook publication royalties from Elsevier BV.

Review Date: 
August 27, 2014
Last Updated:
August 31, 2014