- Design
- Systematic review and meta-analysis of comparative studies
- Population
- 171 adults with actinic keratosis in four studies
- Primary outcome
- Complete lesion clearance at 3 months; illumination pain
- Effect
- Clearance RR 0.86 (0.83-0.89); pain MD -4.44 (-7.18 to -1.71)
This systematic review and meta-analysis found four studies, with 171 participants, comparing indoor or simulated daylight photodynamic therapy with conventional lamp-based PDT for actinic keratosis, using aminolevulinic acid or methyl aminolevulinate. Several used split-face or intra-patient designs.
Complete lesion clearance at three months was lower with the daylight-type approach (RR 0.86, 0.83 to 0.89), though the continuous clearance rate did not differ clearly. Pain during illumination fell by about 4.4 points (95% CI 1.7 to 7.2), and patients more often preferred it. Redness and local skin reactions were similar.
The trade-off is plain: a modest loss in complete clearance for a large gain in comfort. For patients who could not tolerate lamp PDT, or who have large fields of damage, the daylight-type option is reasonable. For thick or resistant lesions, conventional PDT or another treatment remains the stronger choice. The evidence base is small.
- Offer daylight-type PDT to patients for whom pain has limited conventional PDT.
- Prefer conventional PDT when complete clearance of thick or recurrent lesions matters most.
- Review clearance at three months and retreat residual lesions.
- Explain the trade-off between comfort and clearance before choosing.
Why it matters
Pain is a leading reason patients abandon field treatment, and this quantifies what avoiding it costs.
Don't overread it
Only four small studies with 171 participants contributed, so the estimates are imprecise.
The statistics, in plain English
A risk ratio of 0.86 means about 14% fewer lesions cleared completely with the daylight-type method. The narrow interval reflects lesion-level counting in split-face studies, which can make results look more precise than the number of patients justifies.
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