Incidence of secondary malignancies among patients with Waldenström macroglobulinemia: An analysis of the SEER database.

BACKGROUND Waldenström macroglobulinemia (WM) is an indolent malignancy that predominantly affects older individuals who are at risk for secondary malignancies (SMs). The objective of this study was to characterize the incidence of SMs after a diagnosis of WM with the Surveillance, Epidemiology, and End Results (SEER) database. METHODS With SEER-13 data (1992-2011), standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated for the rates of solid and hematologic SMs in WM patients versus the general population. The analysis was stratified by age, sex, race, year of diagnosis, and latency from the WM diagnosis. RESULTS Among 4676 patients with WM, 681 SMs were recorded. The overall SIR was 1.49 (95% CI, 1.38-1.61), and the median time to an SM was 3.7 years. The cumulative incidence of SMs was 10% at 5 years and 16% at 10 years. The risk was significantly increased for cancers of the lungs, urinary tract, and thyroid; melanoma; aggressive lymphoma; and acute leukemia. The SIR for SMs in patients with WM was increased, regardless of age, sex, race, or year of diagnosis. CONCLUSIONS Patients with WM had a 49% higher risk of SMs than the general population. The selectively increased risk for hematologic SMs and certain solid SMs may be associated with transformation, therapy, and immune dysregulation.