Ethnic Disparities in Myeloma Outcomes | Muzaffar Qazilbash, MD | #ASH24

My name is Muzaffar Qazilbash. I am a professor of medicine at MD Anderson Cancer Center in the Department of Stem Cell Transplantation. I'm going to talk about one of our studies, which will be presented in the poster session this coming Monday on December 9th.

We looked at the outcomes of our myeloma patients and how they do after various treatments. We also examined their risk factors, cytogenetics, disease stage, and the different induction regimens they received. One very important area, both from our standpoint as well as from the patient's standpoint, is the question: What about the outcomes in different racial or ethnic groups?

There are a number of factors—whether biological, demographic, or socio-economic—that can play a role in these outcomes. If you look at the data, the results are all over the place. However, something that stands out in various ethnic minorities in the United States is that some studies show that outcomes tend to be a little worse. But then, when you look at access to healthcare, the worse outcomes tend to get neutralized.

So, we looked at our database and identified close to 2,000 patients. Our patients self-identify as belonging to a racial or ethnic group. Out of these 1,960+ patients, about 353 identified themselves as African American, 400+ identified as Hispanic or Latino, and more than 1,100 patients—roughly 60%—identified as non-Hispanic white.

We looked at their outcomes, and all of them received stem cell transplant. Prior to that, they received induction chemotherapy with various regimens. This study was done over 17 or 18 years, so we had long follow-up across different treatment periods.

We first looked at whether there were any differences in the characteristics of those patients beyond their ethnic groups. More or less, they were similar—roughly the same age, and they received similar treatments, except for the patients who identified themselves as Latino or Hispanic. Fewer of them—less than 40%—actually received a combination of proteasome inhibitors and an immunomodulatory drug like lenalidomide, which was less than the other groups where it was more than 50% or 60%. Other than that, the groups were pretty similar.

Then we looked at their outcomes. Our primary outcome was the response rates. In the patients who identified themselves as Latino or Hispanic, fewer of them achieved a deeper response. About 80% had very good partial remission at their last evaluation, compared to about 90% in the other two ethnic or racial groups.

We also looked at progression-free survival. For myeloma patients over the period they were studied, we saw that in African Americans, it was more than four years; in non-Hispanic white patients, it was more than five years; but in Hispanic or Latino patients, it was only 3.2 years. So, it was significantly shorter than in the other ethnic or racial groups.

There was no difference in their high-risk status, and so one thing that stood out was that there was no major difference in overall survival, but definitely progression-free survival was lower in the Latino/Hispanic population. The only thing we found in that group was that fewer patients received the optimal induction regimen.

If that had a role to play, it's hard to tell in a retrospective study where patients had already been treated and there could be some missing information or other factors that we did not know.

These were the important results. This could be a hypothesis-generating finding, and we think others should look at their databases. There are the CIBMTR and the International Bone Marrow Transplant Registry databases where this question can be asked, and others can verify these results. This was an intriguing finding, and we thought it was definitely worth presenting at the meeting.

This was a retrospective study, and one way of looking at it is to see if the results hold true at other places as well. It could just be something that happened at one center, or there could have been flaws in how the data were collected. But if this finding is consistent, we need to identify the factors at play. Is it a biological factor? Because, again, there is no uniform Latino or Hispanic group—people come from different countries, backgrounds, and states.

We need to ask whether this is a biological factor, if it has to do with socio-economic status, or if it’s related to access to healthcare. Are these patients coming from backgrounds where they do not make it to major oncology and hematology centers, or are they not getting the optimal treatment because they lack access?

These are the kinds of questions that need to be explored in the future. And if those factors are at play, then it becomes more of a policy issue. As physicians and researchers, we need to do everything we can to improve access, so there is a more equitable distribution of treatment, which hopefully will translate into better outcomes for those who have somewhat worse outcomes than others.