Risk factors for non-melanoma skin cancer in patients with essential thrombocythemia and polycythemia vera.

ABSTRACT

OBJECTIVES: Population-based studies have reported an increased incidence of skin cancer in patients with essential thrombocythemia (ET) and polycythemia vera (PV). We have examined the risk factors for non-melanoma skin cancer (NMSC) in patients diagnosed with ET or PV during 1973-2012. METHODS: A case-control study was performed to compare the clinical and treatment-related data of 51 ET/PV patients who had NMSC with that of 401 patients who did not. We also evaluated whether polymorphisms in 12 genes involved in DNA integrity predisposed to NMSC. RESULTS: By multivariate logistic regression analysis, risk factors for NMSC were older age (OR 1.7, 95% CI 1.3-2.1, P < 0.001), male sex (OR 2.1, 95% CI 1.1-3.8, P = 0.023), higher cumulated hydroxycarbamide dose (OR 1.3, 95% CI 1.1-1.7, P = 0.017), and busulphan exposure (OR 3.2, 95% CI 1.05-10.0, P = 0.041). On the time-to-event prognostic model, factors independently associated with increased cumulative incidence of NMSC were age (5% increased risk per year; P < 0.001), male sex (91% increased risk; P = 0.022), and hydroxycarbamide exposure (22% increased risk; P = 0.065). No susceptibility gene variant was identified. CONCLUSIONS: These findings suggest that the risk to develop NMSC in ET/PV patients results from the combined effect of common risk factors (age, male sex) together with cytoreductive treatment.