In a study of 358 patients with HCL treated with cladribine, 8% (27/358) developed second tumors.18 According to the Surveillance, Epidemiology and End Results (SEER) data, of 3104 patients with HCL, the incidence of second cancer was 32% compared to 23% in the general population (SIR=1.2; 95% CI 1.1–1.4 for all, 6.6 for Hodgkin lymphoma, 5.0 for non-Hodgkin lymphoma and 3.6 for thyroid cancer.30 In our study, one patient (2%) died of diffuse large B cell lymphoma 70 months after CDA therapy. Here, CDA is linked to thyroid cancer.