Treatment Disparities in Minority Groups with Multiple Myeloma at a Large Safety-Net Hospital
Authors: Dennis Michael , Cirstea Diana , Maoz Asaf , Lerner Adam , Patel Ami K. , Sarosiek Shayna 
Published: October 2019

Background: Outcomes in multiple myeloma (MM) have improved in recent years, but disparities among racial-ethnic groups persist (Costa, 2017; Ailawadhi, 2012; Waxman, 2010). Differences in disease biology, treatment modalities, and access to care are likely explanations for these disparities. Currently the preferred induction therapy for MM is a three-drug regimen, such as bortezomib/cyclophosphamide/dexamethasone (VCD), bortezomib/lenalidomide/dexamethasone (VRD) or carfilzomib/pomalidomide/dexamethasone (KPd). This is often followed by high-dose melphalan with autologous stem cell transplant (HDM/SCT) and maintenance therapy. Older or frail adults may not tolerate this three-drug approach or HDM/SCT. Two-drug regimens without HDM/SCT are acceptable options in these groups. This retrospective study was designed to explore the utilization of preferred induction therapy and HDM/SCT across racial-ethnic groups at Boston Medical Center.

Results: One hundred sixty-eight patients with MM were treated at our institution between 2004 and 2017. Sixty-six percent were non-Hispanic Black (NHB), 20% were non-Hispanic White (NHW), and 14% were Hispanic. The average age was 63 years and 56% of the population was male. There was no significant difference in age or sex between the NHB, NHW, and Hispanic groups. Only 83 patients (49%) received a three-drug induction regimen. Forty-six (51%) were < 65 years old, while 37 (48%) were ≥ 65 years old. The utilization of standard induction therapy was significantly different among racial-ethnic groups < 65 years old. Thirteen NHW patients (76%) received triplet induction therapy, compared to only 10 Hispanics (63%) and 23 NHB patients (40%) (p=0.02). A similar trend was observed in regards to treatment with HDM/SCT within the first year after diagnosis for patients age < 65 years and triplet therapy in patients undergoing HDM/SCT (any age), although these trends did not reach statistical significance (47% NHWs, 31% Hispanics, and 28% NHBs, p=0.31 and 91% NHWs, 78% Hispanics, and 58% NHBs, p=0.11 respectively). There were no significant differences among groups age ≥ 65 years in regards to triplet induction therapy, HDM/SCT within the first year, or HDM/SCT any time after diagnosis. The median time to HDM/SCT and overall survival were not significantly different between racial-ethnic groups, regardless of age above or below 65 years.

Conclusion: NHB and Hispanic patients less than 65 years old are less likely to receive a standard three-drug induction regimen. There is also a trend towards fewer patients receiving HDM/SCT in the first year after diagnosis among these groups compared to NHW patients. Our study did not confirm a survival benefit in NHB patients under age 65, which has been reported in prior studies (Fillmore, 2018; Waxman, 2010). The lack of benefit seen in this study could be related to lower rates of three-drug induction therapy and HDM/SCT in the NHB group. Further research is needed to explore patient co-morbidities, socioeconomic factors, and physician biases to determine why minority groups have less utilization of standard therapies.

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Disclosures

No relevant conflicts of interest to declare.