Patients with cutaneous T-cell lymphoma (CTCL) are at a higher risk of developing second malignancies. However, rates of incidence vary significantly across studies.

A systematic review and meta-analysis of articles published between 1950 and 2019 was performed to evaluate the risk of second malignancies in patients with CTCL.

We identified 10 eligible studies, including 12 patient cohorts, with 5.9% to 16.8% of patients developing second malignancies. All studies showed a male predominance for patients developing second malignancies. The mean age across the studies ranged from 44.6 to 68.0 years. The time between the diagnosis of CTCL and second malignancy ranged from 2.1 to 5.4 years (mean, 3.29 y; 95% confidence interval [CI], 2.69-5.15). Meta-analysis showed a standardized incidence ratio of 2.18 (95% CI, 1.43-2.93) for all malignancies. The standardized incidence ratios were 15.25 (95% CI, 7.70-22.79) for Hodgkin lymphoma, 4.96 (95% CI, 3.58-6.33) for non-Hodgkin lymphoma, 1.69 (95% CI, 1.18-2.21) for lung cancer, 1.72 (95% CI, 1.18-2.21) for bladder cancer, and 3.09 (95% CI, 1.77-6.43) for melanoma.

We find that patients with CTCL are at increased risk of second malignancies, especially Hodgkin and non-Hodgkin lymphoma, lung cancer, bladder cancer, and melanoma. These findings provide evidence of a population at increased risk of malignancy. Early detection may decrease the morbidity burden of second malignancies, thus providing a strong rationale for prospective screening studies.