The Impact of Hispanic Ethnicity on Disease Characteristics in Multiple Myeloma (2022)

INTRODUCTION: While the racial disparities in multiple myeloma between those of African descent and Whites are well-documented, there is a paucity of data on other racial/ethnic minorities, such as Hispanics. Most recently, Kaur, et al. (Clin Lymphoma Myeloma Leuk, 2021) found that compared to other ethnicities, Hispanics residing in New York were younger at diagnosis, had a higher proportion of early-stage disease, did not differ by cytogenetic abnormalities, and had better overall survival with equal access to treatment. However, specific FISH probes tested and treatment regimens in myeloma have substantially changed since 2018. To our knowledge, no study has characterized the biology and clinical outcomes of Hispanics since 2018, a question of import given the national drive to improve outcomes and access to cancer care in minorities. METHODS: A retrospective cohort study was conducted of all patients newly diagnosed with multiple myeloma from January 2018 to December 2021 at our institution, Columbia University Irving Medical Center (CUIMC), to determine if Hispanics differed from non-Hispanics in terms of clinical characteristics and outcomes. As CUIMC is situated in Washington Heights, NY, a neighborhood comprised predominantly of individuals of Dominican ancestry, a large proportion of its patient population self-identifies as Hispanic. Two-sided Fisher's exact tests were used to test for differences between categorical values, and two-sided Wilcoxon rank sum tests were used to compare continuous variables. Survival analysis was done using the Kaplan-Meier method; differences between survival curves were evaluated using the two-sided log-rank test and a threshold of p<0.05 for two-sided statistical significance. RESULTS: Among the 201 patients diagnosed with multiple myeloma between 2018-2021, 76 (38%) self-identified as Hispanic. Among non-Hispanic patients (n=125), 52% were non-Hispanic White, 35% were non-Hispanic Black, 11% were Asian/Pacific Islander, and 2% were other/unknown. Hispanics did not differ from non-Hispanics in terms of age at diagnosis (69 vs. 67 years, respectively, p=0.274), proportion of light-chain myeloma (24% in both, p=0.975), hypercalcemia at diagnosis (15% vs. 17%, respectively, p=0.719), or renal insufficiency at diagnosis (eGFR <60, 52% vs. 49%, respectively, p=0.659). Both ISS and R-ISS stages at presentation were comparable between ethnicities (Table 1). The median follow-up of surviving patients was 23 months. Notably, Hispanics had a more than 2.5-fold higher incidence of del(1p) compared to non-Hispanics (26% vs. 10%, p=0.026), which led to significantly greater odds of harboring expanded high-risk cytogenetics by FISH (t[4;14], t[14;16], t[14;20], del[17p] or chromosome 1 abnormalities; 74% vs. 55%, p=0.028). Additionally, Hispanics had fewer t(11;14) translocations compared to non-Hispanics (17% vs. 30%, p=0.049). The most common induction regimen was VRD (31.3%), followed by Dara-VRD (13.1%), VCD (13.1%), Dara-RD (8.6%), KRD (5.1%), and Dara-VCD (5.1%); other induction regimens were used in <5% of cases each. Upfront high-dose melphalan autologous stem cell transplantation (HDM-ASCT) was performed in 39% of all patients, with no significant difference by ethnicity. The median PFS of Hispanics was 30.3 months (95%CI 17.6- not reached) compared to 38.2 months (95%CI 33.2- not reached) in non-Hispanics (p=0.15). CONCLUSIONS: Although age at diagnosis, ISS/R-ISS stage, clinical presentation, and rates of HDM-ASCT did not differ by ethnicity, Hispanics were found to have a 2.5-fold higher incidence of del(1p) by FISH. Validated as an adverse cytogenetic prognostic marker in myeloma (Perrot et al., JCO, 2019), the significant increase in del(1p) may translate into decreased PFS, a trend seen here. Longer follow-up is needed in a larger cohort adequately powered to assess whether such cytogenetic differences in Hispanics result in significantly worse long-term outcomes. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal