The association between chronic plaque psoriasis and lympho-haematological malignancies (LHM) remains controversial.
To investigate the risk of LHM in patients with psoriasis according to the best evidence.
A systematic review and meta-analysis of observational cohort studies that assessed the association of psoriasis with different LHMs was performed. Literature search on February 28, 2021 for relevant studies was performed. The random-effects model in conducting meta-analyses was applied. To evaluate the risk of bias the Newcastle-Ottawa scale was employed.
A total of 25 observational studies were selected, comprising collectively 2,501,652 subjects. A significantly increased risk for LHM (HR1.55; 1.24-2.94) and lymphoma (HR1.27; 1.08-1.50) in patients with moderate to severe plaque psoriasis compared to general population was found. In detail, an increased risk for Hodgkin lymphoma (HR1.71; 1.27-2.30), non-Hodgkin lymphoma (HR1.27; 1.08-1.50), multiple myeloma (HR1.32; 1.03-1.69) and leukaemia (HR1.28; 1.00-1.65) was found. The risk of cutaneous T cell lymphoma (CTCL) was markedly augmented in patients with psoriasis (HR6.22; 3.39-11.42).
Possible ascertainment bias related the diagnosis of LHM.
The increased risk of LHM, particularly CTCL, in patients with psoriasis could be related to the exposure to systemic immunosuppressive therapies, comorbidities and sustained immune activation, particularly in the skin.

Copyright © 2021. Published by Elsevier Inc.