Outcome disparities among ethnic subgroups of Waldenström's macroglobulinemia: a population-based study.

Background: Ethnic disparities in cancers are associated with variability in clinical outcomes. We present a Surveillance Epidemiology and End RESULTS (SEER)-based outcome analysis of multiethnic Waldenström's macroglobulinemia (WM) patients.

Methods: Adult WM patients diagnosed in 1992 or later (n = 3,175) were analyzed. Median overall survival (OS) was compared across different ethnicities stratified by year of diagnosis, registry identification, age at diagnosis, sex, and marital status.

Results: African-Americans (AA) had the youngest median age at diagnosis (63 years) and Whites had the oldest (73 years) (p < 0.001). Female gender, a younger age at diagnosis, and a recent year of diagnosis were associated with an improved OS. Hispanics had the worst (5.6 years) while Whites had the best (6.8 years) median OS. A significant interaction existed between median OS, gender, and race (p = 0.007). Among males, AA had the worst (4.3 years) and Asians had the best (7.3 years) median OS. A significant interaction was also noted between median OS, age at diagnosis, and race (p = 0.033). The worst median OS was seen in Hispanics among patients aged >75 years, and in AA among those aged <65 years.

Conclusions: These disparities among WM patients may be multifactorial but need to be explored systematically to better understand the disease biology and for optimal triaging of health care resources.