Examining Outcomes Among Hispanic Patients With Multiple Myeloma

Hispanic and non-Hispanic Black patients with multiple myeloma (MM) more often present with disease at a younger age and with significant renal dysfunction. These factors contribute to poorer survival among all racial/ethnic groups, yet Hispanic patients may have higher overall survival (OS) due to increased use of frontline autologous hematopoietic cell transplantation (AHCT), according to a report published in Clinical Lymphoma, Myeloma & Leukemia.

Gurbakhash Kaur, MD, from John Theurer Cancer Center in Hackensack, New Jersey, and coauthors conducted a retrospective analysis of patients with MM who were included in the Montefiore Medical Center Cancer Registry, the National Program of Cancer Registries, and the Surveillance, Epidemiology, and End Results (SEER) database. Self-reported race and ethnicity data coded in the electronic medical record were identified to stratify assessments of disease characteristics and outcomes. Data also were collected from the Connect MM Registry, a large prospective observational cohort study comprising patients with newly diagnosed MM from 250 centers across the U.S.

While the initial cohort for this analysis included 1,634 patients, a total of 939 patients were included in the final analysis after excluding cases of monoclonal gammopathy of unknown significance, solitary plasmacytomas, and smoldering MM, and after excluding patients with incomplete records.

“With equal access to care, Hispanics [with myeloma] have a good prognosis.”

—Gurbakhash Kaur, MD

The remaining patients were categorized based on their race and ethnicity:

  • Hispanic (n=281; 30%)
  • non-Hispanic Black (n=489; 52%)
  • non-Hispanic white (n=169; 18%)

Overall, the mean age at time of MM diagnosis was 65.6 years. The average age at diagnosis was significantly lower among Hispanic and non-Hispanic Black patients compared with non-Hispanic white patients (64.5 vs. 70.6 years, respectively; p<0.01). This finding was replicated in the Connect MM Registry (p<0.01).

The authors also reported that a higher proportion of non-Hispanic Black (35.3%) and Hispanic (28.8%) patients were diagnosed with MM before age 60, compared with non-Hispanic white patients (16.5%; p<0.01).

In the SEER database, Hispanic patients had the second-highest MM incidence rate after non-Hispanic Black patients across all age groups between 40 and 80 years, they added.
A greater proportion of non-Hispanic Black (61.1%) and Hispanic (56.4%) patients presented with severe renal dysfunction compared with non-Hispanic white patients (48.8%; p=0.02). Hispanic and non-Hispanic Black patients also presented with a significantly higher mean lactate dehydrogenase levels at diagnosis (p=0.01). “These observations indicate that Hispanics present with earlier/lesser-stage disease and similar cytogenetic risk compared to non-Hispanic white and non-Hispanic Black [patients],” the researchers wrote.

Treatment also differed significantly among racial groups: Non-Hispanic white patients more often received triplet-based induction therapy compared with Hispanic and non-Hispanic Black patients (49.5% vs. 43.3% vs. 34.5%; respectively; p=0.02). More Hispanic patients underwent AHCT, compared with non-Hispanic Black and non-Hispanic white patients (59.4% vs. 48.1% and 36.6%; p<0.01).

While the median OS for the entire cohort was 78 months, the median OS was highest for Hispanic patients, at 110 months, compared with non-Hispanic white (69 months) and non-Hispanic Black patients (65 months). “As expected, advanced [disease] risk classification, and a response less than [very good partial response (VGPR)/complete response (CR)] to induction therapy negatively affected survival in the univariate analysis,” the investigators reported. Next, in a multivariate analysis, International Myeloma Working Group risk (IMWG; hazard ratio [HR] = 1.9), response to first therapy line (partial response; HR=0.35; VGPR/CR, HR=0.2), and use of AHCT (HR=0.57) were independently associated with mortality.

“The recognition that with equal access to care Hispanics have a good prognosis is important for clinical practice,” the authors concluded, but they also noted that the study’s implications are limited by its retrospective nature and missing data from patients’ medical records, including data on cytogenetic abnormalities and treatments received.

Study authors report no relevant conflicts of interest.

Reference

Kaur G, Mejia Saldarriaga M, Shah N, et al. Multiple myeloma in Hispanics: incidence, characteristics, survival, results of discovery, and validation using real-world and Connect MM registry data. Clin Lymphoma Myeloma Leuk. 2020 November 21. [Epub ahead of print]

Perspectives

In this single-center retrospective dataset, with validation using a real-world prospective dataset and the SEER registry, Hispanic and non-Hispanic Black patients were found to have a higher incidence of MM, have a younger age at presentation, and were more likely to present with renal dysfunction at diagnosis. However, on multivariate analysis adjusting for key variables such as cytogenetic risk and frontline treatment modalities, the authors found conflicting results with respect to the impact of Hispanic ethnicity on OS.

Kaur et al. suggest that cost, access, and adherence to therapies might explain disparities in outcomes. However, this would not account for the inverse relationship seen with AHCT, where Hispanic patients were more likely to undergo transplantation. This, along with younger age at diagnosis, are likely the key drivers for superior OS for Hispanic patients on univariate analysis in this study.

The retrospective nature of this study is a limitation, especially as it can lead to inconsistent data collection. In this dataset, there was a high degree of missingness for items such as cytogenetic abnormalities and treatments received, making interpretation of these data more challenging. In addition, there are some key discrepancies that need to be resolved. For instance, translocation of chromosomes 4 and 14 [t(4;14)] is seen in approximately 15% of cases of newly diagnosed myeloma, and ranged from only 0 to 1.9% in this dataset, which seems inaccurate. In addition, gain1q is a known high-risk cytogenetic abnormality and was not factored into this analysis.

In future studies, it would be interesting to explore if factors such as high-risk cytogenetic abnormalities are associated with outcomes in Hispanic patients, given that much of our understanding of high-risk disease comes from homogenous cohorts of non-Hispanic white patients.

Benjamin Derman, MD
University of Chicago