Efficacy of non‐ablative 1927‐nm fractional thulium fiber laser for the treatment of Becker's nevus: Intra‐ and interobserver agreement study

To assess the efficacy and safety of a 1927-nm fractional thulium fiber laser treatment for Becker's nevus.A retrospective analysis of patients with Becker's nevus who were treated with a 1927-nm fractional thulium fiber laser was conducted. Grading for lightening was set quarterly by physician global assessment of the pre- and postphotographs (I: <25%; II: 25%-50%; III: 51%-75%; and IV: >75% for marked lightening). Grading validation was exercised using intra- and interobserver agreement analysis among 10 dermatologists to determine the percent of agreement and the intraclass correlation coefficient. Grades I and II were classified as treatment failure.A total of 21 patients were recruited for analysis. The average number of treatment sessions was 2.1 per patient. A total of 13 patients achieved successful outcomes (grades III and IV) while 8 patients experienced treatment failure (grades I and II). Partial recurrence and transient hypopigmentation on adjacent skin were the main adverse effects. Only one patient reported worsening of the nevus. Overall agreement among the raters for the outcomes was graded from "very good" to "excellent," and the intraclass correlation coefficient, kappa, was 0.8.A 1927-nm fractional thulium fiber laser may be effective to ameliorate the pigment of Becker's nevus and achieve acceptable cosmetic outcomes. However, further studies are required in this area to improve and optimize the results.