Background: MF/SS-CTCL-QoL is the first specific questionnaire to measure the quality of life (QoL) of patients with Mycosis Fungoides (MF) and Sézary Syndrome (SS). It was developed by the Cutaneous Lymphoma Foundation.

Objectives: 1) Translate and cross-culturally adapt the MF/SS-CTCL-QoL to Spanish (Spain). 2) To study correlation and concordance of the MF/SS-CTCL-QoL with PROM (Patient Reported Outcome Measurements): EORTC QLQ-C30, Dermatology Life Quality Index (DLQI) and Skindex-29.

Material and methods: Using a 10-step procedure, including expert meetings and surveys of adult patients with MF or SS, a Spanish version of the MF/SS-CTCL-QoL was developed. Subsequently, its comprehensibility, completeness and relevance were evaluated. A correlation study was performed using Spearman's rho coefficient and concordance using the intraclass correlation coefficient (ICC), between MF/SS-CTCL-QoL and the EORTC QLQ-C30, DLQI and Skindex-29 questionnaires.

Results: Translation was satisfactory for professionals and patients, with minimal adaptations required. Excellent correlation (0.8499) was observed between MF/SS-CTCL-QoL and Skindex-29, good (0.7394) with DLQI and poor (0.5602) with EORTC QLQ-C30. Agreement was moderate (0.699) with DLQI, significant (0.865) with Skindex-29 and low (0.568) with EORTC QLQ-C30.

Conclusions: The Spanish version of MF/SS-CTCL-QoL represents a useful tool for the clinical management of patients with MF and SS. It is linguistically equivalent to the original, assesses the same dimensions with an adequate level of comprehensibility. There is an excellent correlation with Skindex-29, good with DLQI and poor with EORTC QLQ-C30.