Expert Addresses Disparities in Hematologic Malignancies for Hispanic Population near US/Mexico Border

Alfonso E. Bencomo-Alvarez, PhD

According to a population study analysis presented during the American Association for Cancer Research Virtual Annual Meeting II, disparities were observed in terms of incidence and survival of hematologic malignancies among Hispanic patients versus non-Hispanic patients living in Texas or near the border of the United States and Mexico.

Overall, 62,753 cases were identified in the Texas Cancer Registry to examine incidence and mortality rates among patients diagnosed with a hematologic malignancy between 1995 and 2016. The malignancies included acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), and chronic myeloid leukemia (CML), as well as acute promyelocytic leukemia (APL).

The investigators found that Hispanic patients were diagnosed at significantly younger ages compared with non-Hispanic patients, and the most significant difference was observed among patients with ALL, where the average age of patients was 41.5 years for Hispanic patients versus 53.4 years for non-Hispanic patients. The risk of developing a malignancy was similar among the 2 groups, but Hispanic patients had a higher incidence of blood cancers in patients 40 years of age or younger, while non-Hispanic patients had a higher incidence of blood cancer in patients over the age of 40 years.

Hispanic populations were associated with worse outcomes as well for patients with ALL and APL. There was also an association for worse outcomes among ALL, AML, CML, and MDS, among patients living near the border. A worse prognosis was also observed among Hispanic patients with lower socioeconomic status and increased comorbidities.

In an interview with Targeted Oncology, Alfonso E. Bencomo-Alvarez, PhD, postdoctoral research associate in the laboratory of Anna Eiring, PhD, at Texas Tech University Health Sciences Center El Paso, discussed his research surrounding disparities in leukemias within the Hispanic community, particularly among the Hispanic population living at the border of Texas, in El Paso, and Mexico.

TARGETED ONCOLOGY: What inspired this research?

Bencomo-Alvarez: I've been working with Dr. Anna Eiring for the past 2 years, and she was very interested in blood cancers, specifically leukemias. Because of that, we wanted to figure it out if we can find some disparities.

We started to look at the retrospective study, moving forward, and now we're planning to do xenograft in mice. They started doing RNA and DNA sequencing from patient samples in bone marrows. Our [goal] is to get at an idea of biomarkers so we can actually find identify within the Hispanic population some characteristics that they could have better treatments from the beginning, or determine if this patient has a certain characteristic in their genes, then we don't start with this treatment. Let's go moving forward with the next treatment, which would be a little bit more aggressive, but it's good to have better prognosis for them.

TARGETED ONCOLOGY: What methods were used to conduct the analysis?

Bencomo-Alvarez: First, we used the Texas Cancer Registry database, and you have to go through the process to get the approvals for the Texas Cancer Registry, and as soon that we have all these data, we do the Kaplan Meier survival curves and forest plot analysis after adjusting for age and sex. We made tests to know that the survival curves are, and we summarized using the meta odds ratio method.

When we do the Kaplan Meier curves, we constructed to describe this survival distribution for Hispanic and non-Hispanic groups. A multivariable COX is very important. With the COX analysis, we were able to make the comparison between Hispanic population and non-Hispanic populations to see, for example, socioeconomic status, other comorbidities, place of residency, if they have health insurance, and what kind of health insurance they have. We were able to figure it out which of these differences we can find and get the significance or not when you do the comparison.

TARGETED ONCOLOGY: In terms of the results, what were the most significant disparities that were seen?

Bencomo-Alvarez: If we look at all of Texas together, we found a disparity in ALL and APL. For the ALL, we found the disparity was in populations younger than 70 years in general, and patients have worse overall survival, even if you follow for more than more than 10 years, so it was very significant. They also got diagnosis at younger ages when we do the comparison to the non-Hispanic population. For APL, the patients has worse survival under 50 years old, and if you see only patients who live on the border versus Hispanic population lives elsewhere in Texas, we observed this in ALL, AML, MDS, and CML, so something's going wrong or something's happening at the border.

We used to have a breach in heavy metals, or metals. They say they have a lot of contamination [in this area] where they work with lead and copper and other stuff, as well, so that [business] closed at the beginning of the century, but it could be something with pollution. It could be, but I'm thinking that a lot of people Mexico, even just across the border, we detect the Hispanic population tends to be a little bit older than the rest of Texas. I think this is because it's easy to live t the border, even if you're American citizen, just to cross over to work and at the end. Also, the elderly may come to the United States and live there. Also, because they don't have insurance at the beginning, they don't go to the doctor. Either way, something's happening with the Hispanic population at the border because they have worse survival than Hispanics in other parts of Texas.

TARGETED ONCOLOGY: Now that we know this disparity to be true, what next steps can be taken to close that gap?

Bencomo-Alvarez: We already set up a biobank, so we're collecting samples from patients in El Paso and all of the county as well, not only El Paso. So far, we have roughly 60 samples, and we've been collecting these for a year already. The next step of this is we already have the samples, so we have cells, we have proteins, we have DNA, and we have RNA. The next step is to do the sequencing to know if we can find any variation and do the comparison with non-Hispanic whites to see if we can find some difference on RNA sequencing or DNA sequencing. However, the final idea is trying to do xenograft, so putting the cells into mice to try to figure out if we can realize what kind of mutation they have. If those mutations are very selective, and that's why they have the disease and do like specific treatments.

We're trying as well to work with other institutions in order to try to be a little bit more informative with the population here and even in Texas as well. [We want to] let them know why if you're illegal in the United States, it doesn't matter. You have to go to the doctor because this and that happened. We have to explain the symptoms because some of the symptoms are very similar. You can have bruises or bleeding, or you feel tired all the time and sleep more than usual, or you get sleep more often than other people. These particular symptoms are very regular, and rarely can I say, “Oh no, he is sleeping just because he’s tired” and they say, “Yeah, but isn't that normal.” Trying to explain those to people and trying to be in touch with these communities in order to reduce it. If we can avoid it, perfect, but at least [we can] reduce the disparity.

TARGETED ONCOLOGY: Is there anything else about the study that you wanted to emphasize?

Bencomo-Alvarez: The idea is this is just the beginning of the process. Our work is already under review for publication, so I hope we can publish before this year ends. It's very important to us that we get published because the idea is to get funds to keep going with this and make a bigger biobank or share samples with other institutions in order to actually know these disparities and try to understand why this is happening. We don't have a lot of samples from the African American population because it is not a huge population here in El Paso and even in Texas, but I think it is very important to only focus on the Hispanic population now to try to [help] all the minorities in the United States.