Epidemiological changes in cutaneous lymphomas: an analysis of 8593 patients from the French Cutaneous Lymphoma Registry*

Abstract

Summary Background Primary cutaneous lymphomas (PCLs) are a heterogeneous group of T‐cell (CTCL) and B‐cell (CBCL) malignancies. Little is known about their epidemiology at initial presentation in Europe and about potential changes over time. Objectives The aim of this retrospective study was to analyse the frequency of PCLs in the French Cutaneous Lymphoma Registry (GFELC) and to describe the demography of patients. Methods Patients with a centrally validated diagnosis of primary PCL, diagnosed between 2005 and 2019, were included. Results The calculated incidence was unprecedently high at 1·06 per 100 000 person‐years. The number of included patients increased yearly. Most PCL subtypes were more frequent in male patients, diagnosed at a median age of 60 years. The relative frequency of rare CTCL remained stable, the proportion of classical mycosis fungoides (MF) decreased, and the frequency of its variants (e.g. folliculotropic MF) increased. Similar patterns were observed for CBCL; for example, the proportion of marginal‐zone CBCL increased over time. Conclusions Changes in PCL frequencies may be explained by the emergence of new diagnostic criteria and better description of the entities in the most recent PCL classification. Moreover, we propose that an algorithm should be developed to confirm the diagnosis of PCL by central validation of the cases.

Epidemiology of cutaneous lymphoma

“…In contrast, studies from the USA based on much larger groups of patients (range 4310–6230) reported a prevalence of 0·64–0·87/100 000 population 4,5 . Therefore, based on the results of these latter studies and the current paper by Dobos et al ., 1 a similar prevalence of CL of around 0·90/100 000 population seems most likely in both Europe and the USA.…”

“…In this issue of the BJD , Dobos et al . present a retrospective analysis of epidemiological data from the French Cutaneous Lymphoma Registry (FCLR) 1 . Based on 779 patients included in 2018 by the FCLR, the authors report an incidence of CL of 0·96 per 100 000 population.…”

“…The strong points of the paper by Dobos et al . include the large number of collaborating centres, the large number of included patients, the long duration of data collection and the consistent use of the World Health Organization–European Organisation for Research and Treatment of Cancer’s classification system, allowing for the observation of changes in the epidemiology of CL over time 1 . Whereas for some well‐described CL subtypes, such as classical MF and lymphomatoid papulosis, the number of cases remained relatively stable over time, a large (sometimes spectacular) increase was observed in other CL subtypes.…”

“…In this issue of the BJD, Dobos et al present a retrospective analysis of epidemiological data from the French Cutaneous Lymphoma Registry (FCLR). 1 Based on 779 patients included in 2018 by the FCLR, the authors report an incidence of CL of 0Á96 per 100 000 population. By comparing patients included in the FCLR database from 2005 to 2009 with patients included from 2010 to 2014, and with patients included from 2014 to 2019, several changes in the prevalence of CL subtypes were found.…”

Mycosis Fungoides and Sézary Syndrome: An Integrative Review of the Pathophysiology, Molecular Drivers, and Targeted Therapy

“…Primary cutaneous T-cell lymphomas (CTCLs) vary in form from those of a very indolent type to extremely aggressive malignancies with bad prognosis. CTCLs are rare diseases with an annual incidence of around seven cases per million population [1]. The most common CTCLs are mycosis fungoides (MF) and Sézary syndrome (SS), which account for around 50% of all primary CTCLs [2,3].…”