Abstract
Background: Methyl‐aminolevulinate‐based photodynamic therapy (MAL‐PDT) has been successfully used in early‐stage mycosis fungoides (MF) lesions. However, the long‐term outcome of initially responding lesions has not been systematically investigated to date. To address this issue, we hereby report a large series of early‐stage MF lesions treated with MAL‐PDT and followed up for 1 year after initial treatment. Objectives: The objective of this study was to retrospectively evaluate short‐ and middle‐term clinical results of MAL‐PDT on early‐stage MF lesions (patches and plaques) and to identify characteristics possibly predictive of effectiveness. Methods: Data from all early‐stage MF lesions (plaques and patches) treated with MAL‐PDT between 2010 and 2017 in a tertiary referral centre were retrospectively collected. Primary endpoints were initial clinical response rated as complete response (CR) or partial response (PR), and the rate of relapse of initially responding lesions was further evaluated 1 year after the last PDT session. Secondary endpoints addressed tolerance and the relevancy of predefined parameters possibly predictive of CR achievement. Results: A total of 62 lesions from 30 patients with early‐stage MF (21 Ia, nine Ib) were treated and analysed. At the 6‐week evaluation, the overall clinical response rate (RR) was 87.25% (55% CR and 32.25% PR) with a mean of 2.7 PDT sessions per lesion. Twenty‐five percent of initially responding lesions relapsed locally within 1 year. Transient, although significant, pain occurred at least once in 30% of patients. In univariate analysis, the location of lesions on sun‐protected areas was the only parameter statistically related to CR, a result confirmed in multivariate analysis. Conclusions: Overall, these data confirm the interest in the use of MAL‐PDT in early‐stage MF even for deep (folliculotropic) lesions with a higher efficiency on sun‐protected areas. Furthermore, this study demonstrates for the first time that the response is often sustained over time. Accordingly, MAL‐PDT should be considered in the management of early‐stage MF, especially in oligolesional forms or in residual lesions refractory to systemic treatment.