Sezary syndrome (SS) is a rare, aggressive and advanced form of cutaneous T lymphoma with a poor prognosis (5-year survival rate varying between 24% and 52%). The treatments are only suspensive with short-term remissions. For the past fifteen years, therapeutic approaches have been based on depleting monoclonal antibodies (anti-CD52, anti-CCR4, anti-KIR3DL2, anti-CD70), or antibody-drug conjugates (anti-CD30). But while the efficacy of mogamulizumab on progression-free survival was reported in the phase III study, no study on a large cohort has compared the current overall survival of patients with Sezary syndrome to that before the era of monoclonal antibodies. In this context, we propose to report a large series of patients with Sézary syndrome in order to compare the current survival of patients with that of the pre-monoclonal antibodies era (1998-2003).

The objective of this study is to assess the evolution of the overall survival of patients with Sezary syndrome since the early use of therapeutic monoclonal antibodies. The underlying hypothesis of this study is that the use of therapeutic monoclonal antibodies has improved the prognosis of these patients. Patients included in this retrospective study are patients with a Sezary syndrome diagnosed between 1998 and 2020.

Inclusion Criteria:

1. Adult patients over 18 years of age
2. Patient with Sezary Syndrome diagnosed between 1998 and 2020

Exclusion Criteria:

1. Patient opposition to research
2. Patient under guardianship or curatorship, unable to express opposition

Adult patient with Sézary syndrome diagnosed between 1998 and 2020