A randomized trial comparing methyl aminolaevulinate photodynamic therapy with and without Er:YAG ablative fractional laser treatment in Asian patients with lower extremity Bowen disease: results from a 12-month follow-up


  • Funding sources This study was supported by research funds from Dong-A University.
  • Conflicts of interest None declared.



Methyl aminolaevulinate photodynamic therapy (MAL-PDT) is an effective treatment for Bowen disease (BD) of the lower extremities. Er:YAG (erbium:yttrium-aluminium-garnet) ablative fractional laser (AFL) treatment removes the stratum corneum to increase MAL uptake and may improve efficacy. However, no studies have directly compared the efficacy of MAL-PDT with and without Er:YAG AFL therapy in treating BD of the lower extremities in Asians.


To compare the efficacy, recurrence rate, cosmetic outcomes and safety between Er:YAG AFL-assisted MAL-PDT (Er:YAG AFL-PDT) and standard MAL-PDT.


Twenty-one patients with a total of 58 BD lesions randomly received either one session of Er:YAG AFL-PDT or two sessions of MAL-PDT in two symmetrical areas. Er:YAG AFL therapy was performed with 550–600 μm ablation depth, level 1 coagulation, 22% treatment density and a single pulse. MAL cream was then applied under occlusion for 3 h and illuminated with a red light-emitting diode lamp at 37 J cm−2. A second session of MAL-PDT was administered 7 days later. Overall response rate, recurrence rate, cosmetic outcomes and safety were assessed at 1 week, 3 and 12 months after treatment.


After 3 months, Er:YAG AFL-PDT was significantly more effective (93·8%) than MAL-PDT (73·1%; = 0·031), and the recurrence rate was significantly lower for Er:YAG AFL-PDT (6·7%) than MAL-PDT (31·6%) at 12 months (= 0·022). No significant difference was found between Er:YAG AFL-PDT and MAL-PDT in terms of cosmetic outcomes or safety.


Er:YAG AFL-PDT showed significantly higher efficacy and lower recurrence rate than did standard MAL-PDT for treating lower extremity BD in an Asian population.