Can the response of port-wine stains to laser treatment be reliably assessed using subjective methods?

Assessing the results of laser treatment of port-wine stains (PWS) is very subjective. Most publications use scoring systems that physically describe the change in PWS after treatment. For results derived from such an analysis to be meaningful, the observers must be able to produce results that not only have a small interobserver variability but are also reproducible. Previous studies have addressed the former but not the latter. The present study was undertaken to investigate this area of concern. Six professionals, experienced in laser work, blindly assessed the response to laser treatment of 20 PWS, on two occasions, 1 month apart. Twenty pairs of comparable clinical photographs (one pretreatment and one post-treatment) were assessed using three different scoring systems commonly used in previous publications. Intrarater concordance between the two sessions was then assessed. Our results demonstrated that the judges could only consistently score results at the extremes of outcome. There was little agreement in the assessment of results lying between these. The judges were, however, consistently able to place a similar proportion of patients in each outcome category. We conclude that, as yet, there is no satisfactory method of monitoring the progress of an individual's PWS following laser treatment. However, the scoring systems examined would seem to be reasonable for presenting the data from patient series.