July 21, 2017
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Race, ethnicity impact use of autologous stem cell transplantation for multiple myeloma

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Hispanic patients with multiple myeloma in the United States demonstrated the lowest usage rate for autologous hematopoietic stem cell transplantation, according to a report by the Center for International Blood and Marrow Transplant Research.

Although it is recommended that autologous HSCT be considered in patients with multiple myeloma, studies have suggested that only approximately 30% of patients undergo transplantation.

Saad Z. Usmani

“Understanding barriers is critical to developing strategies to increase the use of autologous HSCT as a therapeutic option,” Saad Z. Usmani, MD, FACP, director of the plasma disorders program at Levine Cancer Institute at Carolinas HealthCare System and a HemOnc Today Editorial Board Member, and colleagues wrote.

Previous studies have suggested transplantation is underused in black patients compared with white patients.

However, limited data exists on the use and efficacy of transplantation in Hispanic patients, who are considered the fastest growing population in the United States.

Usmani and colleagues used the Center for International Blood and Marrow Transplant Research and SEER databases to calculate the incidence of multiple myeloma and derive a stem cell transplantation utilization rate to identify differences between racial and ethnic groups.

Researchers defined stem cell transplantation utilization rate as the number of new transplantations in a year divided by the number of patients with newly diagnosed multiple myeloma for that year.

Researchers identified 28,450 patients who underwent autologous HSCT from 2008 to 2014, including 18,046 non-Hispanic white patients, 4,123 non-Hispanic black patients and 1,933 Hispanic patients.

The overall autologous HSCT utilization rate estimate increased from 19.8% (95% CI, 18.5-19.6) in 2008 to 30.8% (95% CI, 30-31.6) in 2013.

From 2008 to 2014, stem cell transplantation utilization rates increased across all groups, including from 8.6% (95% CI, 7.9-9.4) to 16.9% (95% CI, 15.6-18.3) among Hispanics; from 12.2% (95% CI, 11.4-13) to 20.5% (95% CI, 19.4-21.8) among non-Hispanic blacks; and from 22.6% (95% CI, 21.8-23.9) to 37.8% (95% CI, 35.5-38) among non-Hispanic whites.

Pretransplantation characteristics significantly varied among groups. For example:

  • The Hispanic group was younger than the non-Hispanic black group and the non-Hispanic white group (median age, 57 years vs. 58 years vs. 61 years; P < .001);
  • A smaller proportion of patients aged older than 60 years underwent transplantation among the Hispanic and the non-Hispanic black groups than among the non-Hispanic white group (39% vs. 42% vs. 56%; P < .001);
  • A greater proportion of women underwent transplantation in the non-Hispanic black and Hispanic groups than the non-Hispanic white group (50% vs. 43% vs. 41%; P < .001);
  • Karnofsky scores of less than 90% and an HSCT comorbidity index score of 3 or more were more common in the non-Hispanic black group (44% and 38%) than the Hispanic (39% and 24%) and non-Hispanic white groups (39% and 34%; P < .001);
  • A greater proportion of Hispanics had stage III disease than non-Hispanic blacks and non-Hispanic whites (57% vs. 54% vs. 52%; P < .001);
  • A greater proportion of non-Hispanic white patients than Hispanic and non-Hispanic black patients proceeded to transplantation less than 6 months after diagnosis (30% vs. 23% vs. 21%; P < .001); and
  • A greater proportion of Hispanic patients demonstrated a very good partial response or better before transplantation compared with non-Hispanic black and non-Hispanic white patients (48% vs. 45% vs. 44%; P < .005).

Usmani and colleagues observed no difference between groups for transplantation-related mortality, PFS or OS.

As a result, the researchers noted the importance of conducting additional studies to understand why a disproportionate number of black and Hispanic patients fail to undergo transplantation for multiple myeloma.

“It is also important that race and ethnicity should be clearly delineated as factors that do not impact outcomes in terms of proceeding to transplantation,” Usmani and colleagues wrote. “Further education on early referral to transplantation centers for all populations is critical, and efforts should be made to expand community outreach across racial and ethnic groups. Development of strategies to increase access to transplantation across all ethnic groups, with an emphasis on those who are currently underutilizing this modality, is urgently needed.”

Navneet S. Majhail

An individualized approach may help to address the underutilization of and poor access to autologous HSCT, Navneet S. Majhail, MD, MS, director of the Blood and Marrow Transplant Program at Cleveland Clinic, wrote in an accompanying editorial.

“Each patient who does not [undergo] transplantation has a unique disparity ‘risk-profile,’ comprising social, cultural, economic, and medical factors that are best addressed by interventions specific to their situation,” he wrote.

These interventions would be evidence-based and generated by “high-quality and rigorous” studies, Majhail wrote.

“Ultimately, innovations in myeloma therapy need to be grounded in the reality of health care disparities,” he added. “It is critical that all patients, irrespective of race/ethnicity, are given an opportunity to benefit from established and new therapies, including [autologous HSCT].” – by Kristie L. Kahl

Disclosure: Usmani reports he has no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures. Majhail reports he receives fees from Anthem Inc. and Sanofi Genzyme.