Abstract PR04: Understanding outcome disparities in multiple myeloma: A multiethnic comparison of clinical characteristics in Hispanics
Authors: Belachew Alem A. , Tang Xiaohui , Sandblom Lily K. , Acevedo-Soto Luis A. , Orlowski Robert Z. , Manasanch Elisabet E. , Hildebrandt Michelle A.T. 
Published: September 2020

Purpose: Although Hispanics are the fastest-growing minority population in the United States, little is known regarding clinical attributes of multiple myeloma (MM) in this group. Here, we ascertain unique MM disease characteristics in Hispanics when compared to a multiethnic MM patient population.

Methods: Self-reported 152 Hispanic, 219 non-Hispanic black (NHB), and 275 non-Hispanic white (NHW) MM cases were selected from the MD Anderson Cancer Center Patient and Survivor Cohort. Patient demographics, history of premalignancy, MM (Ig) subtypes, and baseline diagnostic and prognostic indicators were then abstracted for each patient. Comparative cross-ethnic analysis was conducted using chi-squared tests and student t-tests as appropriate for categorical and continuous variables. Overall survival was determined from date of death or last date of follow-up, and Kaplan-Meyer curves were utilized to visualize outcome by ethnic group.

Results: Hispanic MM cases were significantly younger (57.0) compared to NHW cases (62.1; P=0.003) and similar to NHB cases (57.4; P=0.77). IgG comprised the majority (54.3%) of MM subtypes in Hispanic patients, followed by IgA (24.5%) and light chain restricted (11.9%). Hispanics had the least incidence of premalignant MGUS and smoldering myeloma (8.50%) compared to NHB (21.9%; P=0.0006) and NHW patients (13.8%; P=0.12). Cross-ethnic assessment of baseline blood biomarkers revealed a significant difference in median beta-2-microglobulin levels between the Hispanic (4.60) and NHB (3.30) cases (P=0.03). In addition, baseline median hemoglobin levels in Hispanics (11.2) were significantly higher from that in NHB cases (10.0; P=0.0001) but were similar to NHW patients (11.2). Furthermore, the median M spike at diagnosis was significantly lower in Hispanics (2.45) compared to both NHW (3.4) and NHB (3.4) study groups (P=0.011 for both). Interestingly, the median overall survival time for Hispanic patients (63.9 months) was 15 months longer than NHB (48.8 months; log-rank P=0.10) and over 21 months longer than NHW MM patients (42.4 months; log-rank P=0.016).

Conclusion: We identified distinct clinical features in Hispanic MM patients that differed from NHW and NHB cases. Findings of our study may provide a better understanding for cancer diagnosis and management in the Hispanic populations. Ongoing efforts include assessing differences by genetic ancestry to refine clinical characterization among this highly admixed population.

This abstract is also being presented as Poster B097.

Citation Format: Alem A. Belachew, Xiaohui Tang, Lily K. Sandblom, Luis A. Acevedo-Soto, Robert Z. Orlowski, Elisabet E. Manasanch, Michelle A.T. Hildebrandt. Understanding outcome disparities in multiple myeloma: A multiethnic comparison of clinical characteristics in Hispanics [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr PR04.