Risk of lymphohematologic malignancies in patients with chronic plaque psoriasis: A systematic review with meta-analysis

Background The association between chronic plaque psoriasis and lymphohematologic malignancies (LHMs) remains controversial. Objective To investigate the risk of LHMs in patients with psoriasis according to the best evidence. Methods A systematic review and meta-analysis of observational cohort studies was undertaken to assess the association of psoriasis with different LHMs. A literature search for relevant studies was performed on February 28, 2021. The random-effects model in conducting meta-analyses was applied. To evaluate the risk of bias, the Newcastle-Ottawa Scale was employed. Results A total of 25 observational studies were selected, comprising collectively 2,501,652 subjects. A significantly increased risk for LHM (hazard ratio [HR], 1.55; 1.24-2.94) and lymphoma (HR, 1.27; 1.08-1.50) in patients with moderate-to-severe plaque psoriasis compared to the general population was found. In detail, increased risks for Hodgkin lymphoma (HR, 1.71; 1.27-2.30), non-Hodgkin lymphoma (HR, 1.27; 1.08-1.50), multiple myeloma (HR, 1.32; 1.03-1.69), and leukemia (HR, 1.28; 1.00-1.65) were found. The risk of cutaneous T-cell lymphoma was markedly augmented in patients with psoriasis (HR, 6.22; 3.39-11.42). Limitations Possible ascertainment bias related to the diagnosis of LHMs. Conclusion The increased risk of LHMs, particularly cutaneous T-cell lymphoma, in patients with psoriasis could be related to exposure to systemic immunosuppressive therapies, comorbidities, and sustained immune activation, particularly in the skin. The association between chronic plaque psoriasis and lymphohematologic malignancies (LHMs) remains controversial. To investigate the risk of LHMs in patients with psoriasis according to the best evidence. A systematic review and meta-analysis of observational cohort studies was undertaken to assess the association of psoriasis with different LHMs. A literature search for relevant studies was performed on February 28, 2021. 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 (hazard ratio [HR], 1.55; 1.24-2.94) and lymphoma (HR, 1.27; 1.08-1.50) in patients with moderate-to-severe plaque psoriasis compared to the general population was found. In detail, increased risks for Hodgkin lymphoma (HR, 1.71; 1.27-2.30), non-Hodgkin lymphoma (HR, 1.27; 1.08-1.50), multiple myeloma (HR, 1.32; 1.03-1.69), and leukemia (HR, 1.28; 1.00-1.65) were found. The risk of cutaneous T-cell lymphoma was markedly augmented in patients with psoriasis (HR, 6.22; 3.39-11.42). Possible ascertainment bias related to the diagnosis of LHMs. The increased risk of LHMs, particularly cutaneous T-cell lymphoma, in patients with psoriasis could be related to exposure to systemic immunosuppressive therapies, comorbidities, and sustained immune activation, particularly in the skin.