Skin cancer in essential thrombocythaemia and polycythaemia vera patients treated with hydroxycarbamide

Hydroxycarbamide (HC) is used as a cytoreductive treatment in myeloproliferative neoplasms (MPN). Observational studies have raised the possibility that HC contributes to the development of secondary malignancies, including skin tumours in MPN patients. In this retrospective observational study, we report a single-centre experience of 324 HC-treated MPN patients with long-term follow-up, compared to 47 MPN patients not on HC. Thirty-three patients (10.2%) (HC) versus one patient (2.1%) (no HC) developed skin tumours during follow-up (Hazard ratios [HR] 5.70, 95% confidence intervals 0.66-48.09,  = 0.112). However, male gender, age at MPN diagnosis, type of MPN (polycythaemia rubra vera) and previous history of skin cancer were prognostic variables associated with development of skin cancer.