From the Journals

Which AK treatment has the best long-term efficacy? A study reviews the data



The four most effective treatments for long-term clearance of actinic keratosis (AK) are photodynamic therapy with aminolevulinate (ALA-PDT); imiquimod, 5%; photodynamic therapy with methyl aminolevulinate (MAL-PDT); and cryosurgery, results from a systemic review and meta-analysis suggest.

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To date, many studies have reported that “most interventions are superior to placebo in terms of lesion clearance and improving the cosmetic image,” corresponding author Markus V. Heppt, MD, MSc, and colleagues wrote in a study published online Aug. 4, 2021, in JAMA Dermatology.

“However, most randomized clinical trials (RCTs) and meta-analyses focused on short-term outcomes that are evaluated within 3-6 months after treatment, although AK is increasingly being considered a chronic condition and reducing the incidence of cSCC [cutaneous squamous cell carcinoma] should be the ultimate goal of treatment,” they said. In addition, most treatments have been compared with placebo “and head-to-head comparisons are widely lacking, limiting the possibility to cross compare distinct active treatments. To this end, no evidence-based recommendation regarding the long-term efficacy of interventions for AK exists.”

To determine the long-term clearance rates of treatments used in adults with AK, a precursor of cSCC, Dr. Heppt, of the department of dermatology at University Hospital Erlangen (Germany), and colleagues drew from 15 randomized clinical trials that reported sustained clearance rates after at least 12 months of treatment and were published up to April 6, 2020. They conducted the review by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guideline and its extension for network meta-analyses (PRIMSA-NMA) and using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process to determine the certainty of the evidence for network meta-analyses.

The study population included 4,252 patients. Among 10 studies included in a network meta-analysis for the outcome of participant complete clearance, ALA-PDT showed the most favorable risk ratio profile, compared with placebo (RR, 8.06; moderate-quality evidence on GRADE), followed by imiquimod, 5% (RR, 5.98; very-low-quality evidence on GRADE); MAL-PDT (RR, 5.95; low-quality evidence on GRADE); and cryosurgery (RR, 4.76; very-low-quality evidence on GRADE).

ALA-PDT had the highest RR in the network meta-analyses for lesion-specific clearance (RR, 5.08; moderate-quality evidence on GRADE).

“Although ALA-PDT showed the most favorable RR and was ranked best among all interventions, the relative efficacy values and treatment rankings must be interpreted with caution,” because of the low certainty of evidence and few direct, head-to-head comparisons, the authors emphasized. “In particular, it remains elusive how to translate the distinct RR values into clinical relevance. We are hesitant to derive hierarchical or algorithmic treatment recommendations from our results.”

“The current meta-analysis notes that there are conflicting results in different studies,” said Christine Ko, MD, professor of dermatology and pathology at Yale University, New Haven, Conn. who was asked to comment on the study. “Sustained participant complete clearance of actinic keratoses at 12 months is used as an outcome measure, although the authors comment that prevention/reduction of squamous cell carcinoma might be the more valid outcome measure.”

In her clinical experience, Dr. Ko said that patients often have good, sustained clearance of AKs with field treatment using a topical medication like 5-fluorouracil. “Patients can also have a good result with photodynamic therapy,” she said. “The paper’s results therefore do reflect what I have seen in my own practice. I also agree with the authors that, while it is difficult to measure, a meaningful outcome for patients is reduction/prevention of squamous cell carcinoma. It would be useful to have data on which treatment of actinic keratosis is best to reduce/prevent squamous cell carcinoma.”

The authors acknowledged limitations of the study, including the fact that field-directed treatments such as imiquimod, PDT, and fluorouracil were compared with lesion-directed approaches such as cryosurgery, “which may limit the generalizability of our results.” They concluded that their analysis “provides data that might contribute to an evidence-based framework to guide the selection of interventions for AK with proven long-term efficacy and sustained AK clearance.”

The analysis did not include data on tirbanibulin, a first-in-class dual Src kinase and tubulin polymerization inhibitor that was approved by the FDA for the topical treatment of AKs on the face or scalp in December 2020.

Dr. Heppt disclosed that he has been a member of the advisory boards of Almirall Hermal and Sanofi-Aventis and has received speaker’s honoraria from Galderma and Biofrontera. Many of his coauthors also reported having relevant financial disclosures. Dr. Ko reported having no relevant disclosures.

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