What differences in outcomes exist in Hispanic patients being treated for lymphoplasmacytic lymphoma and waldenstrom macroglobulinemia?

Abstract

e19541 Background: Lymphoplasmacytic Lymphoma (LPL) and Waldenstrom Macroglobulinemia (WM) are both rare diseases with little known about their longterm outcomes in ethnic minorities. Overall, the 5- and 10-year survival of this disease has improved over the last 60 years (Blood, PMID: 24948623), but few studies have explored outcomes in Hispanic (HI) patients. We analyzed demographics, treatment patterns and outcomes in patients diagnosed with LPL and WM comparing HI and Non-Hispanics (NH) in the US. Methods: Data was analyzed on LPL and WM patients in the US reported to the Surveillance, Epidemiology, and End Results (SEER) analyzing patient characteristics, age-adjusted incidence rate, and survival rate among HI and NH patients. Results: HI were diagnosed at a younger median age on both LPL and WM cohorts compared to NH (p <0.001). There was a higher percentage of HI patients diagnosed with LPL and WM before the age of 60 compared to that of NH (p <0.001). Regarding race of patients with LPL, most of both HI and NH patients identified as whites (94% vs 86%), followed by blacks (2% vs 6%). Regarding stage, a majority of both HI (50%) and NH (60%) patients diagnosed with LPL were Stage IV. In terms of radiation, 7% of HI patients with LPL received it, compared to 4% of NH patients (p=0.027). On survival analysis for LPL patients, the survival probability at 2, 5 and 10 years (y) of HI vs NH were similar. There was not an OS difference favoring HI/NH (p=0.49). On survival analysis for WM patients, the survival probability at 2, 5 and 10 y of HI vs NH were similar. The median survival time for patients with WM was similar between HI and NH patients and there was not OS difference favoring HI vs NH (p=0.16). On multivariate analysis for LPL and WM, those diagnosed over the age of 80 had worse OS compared to those younger than 60 (95% CI; 4.8-8.1 and 2-3.4, respectively). No OS benefit when adjusting for stage was observed for either LPL or WM. Conclusions: In LPL and WM patients HI patients were diagnosed at younger ages compared to NH for both LPL and WM, and more likely to be diagnosed before the age of 60. The median survival rates were similar between HI and NH patients diagnosed with both LPL and WM. These findings may be confounded by earlier diagnosis in HI patients; however, further studies are needed exploring biological ethnic differences to explain early diagnosis in LPL and WM among HI.