Thin actinic keratoses on the face or scalp were 14% more likely to clear completely in patients treated with photodynamic therapy, compared with cryotherapy, in a meta-analysis of four studies including 641 patients.
Complete clearance 3 months after treatment was significantly more likely in the 2,170 actinic keratoses treated by photodynamic therapy (PDT), compared with 2,174 actinic keratoses treated by cryotherapy, Dr. Gayatri Patel and her associates reported.
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According to the researchers, photodynamic therapy was more successful than cryotherapy for actinic keratosis.
The data came from randomized trials with 10 or more participants in which the PDT used topical aminolevulinic acid hydrochloride or methyl aminolevulinate hydrochloride, the most widely available PDT stabilizers in North America and Europe. Methyl aminolevulinate recently was withdrawn from the U.S. market but remains common in Europe, noted Dr. Patel of the University of California, Davis, and her associates.
The study results were published online in JAMA Dermatology (2014 Aug. 27 [doi:10.1001/jamadermatol.2014.1253]).
The results suggested that PDT works better on thinner actinic keratoses. Grade 1 (thin) actinic keratoses on the face or scalp were 86% more likely to clear by 12 weeks after PDT, compared with cryotherapy, the investigators reported.
Dr. Gayatri Patel
Only one of the fours studies found higher efficacy rates for cryotherapy, compared with PDT, and more than 60% of lesions in that study were grade 2 (moderately thick, easily felt) or grade 3 (very thick and/or obvious) actinic keratoses. The other three studies in the meta-analysis excluded thicker lesions or favored thinner ones, the researchers noted.
They excluded from the meta-analysis two other studies that compared PDT with cryotherapy for actinic keratoses because of incompatible follow-up times. They reviewed 13 studies in all, including studies involving treatment of actinic keratosis with imiquimod, fluorouracil, or carbon dioxide laser, but could not meta-analyze data on these other treatments because of different outcome measures and follow-up times or lack of a comparator.
Photosensitivity, pain, erythema, and pruritus were common after PDT. Cryotherapy induced pain and pruritus, but at lower rates than did PDT. Hypopigmentation occurred in 33% of patients after cryotherapy and in 9% after PDT in one study.
Satisfaction ratings by patients and unblinded investigators tended to favor PDT over cryotherapy, perhaps because PDT may produce ancillary cosmetic improvements when treating actinic keratosis, Dr. Patel and her associates speculated.
The findings were limited by the poor quality of the studies, which were lacking double-blind design and description of randomization methods, but no sources of bias were evident, and the large number of patients and relatively similar treatment locations were strengths of the analysis, they said.
Dr. Patel reported having no financial disclosures.
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