1. Nalley, Catlin

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A recent study found that Hispanic patients with certain blood cancers who live along the U.S./Mexico border in El Paso, Texas, had lower overall survival than those living in other parts of the state, according to data presented at the AACR Virtual Annual Meeting II, held June 22-24 (Abstract 4343).

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"The Hispanic population represents the largest and fastest growing minority group in the U.S., representing 18 percent of the total population," noted Alfonso Bencomo-Alvarez, PhD, a postdoctoral research associate in the laboratory of Anna Eiring, PhD, at Texas Tech University Health Sciences Center El Paso, during a press briefing prior to the conference. "Hispanics in the U.S. tend to live in the southern part of the country, with the majority residing in California, Texas, and Florida.


"Cancer is the leading cause of death among Hispanics in the United States," he explained. "Furthermore, Hispanics are more likely to be diagnosed with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) at younger ages and typically have worse overall survival than non-Hispanic white patients."


Recognizing the need for a better understanding of disparities in blood cancer incidence and survival among Hispanics in Texas and at the U.S./Mexico border, Bencomo-Alvarez and colleagues sought to fill this knowledge gap.


"In contrast to the Hispanic population across the U.S., which is heterogeneous and includes Hispanics from various countries, the majority of Hispanics in Texas and at the border are Mexican," he noted, in a statement. "Therefore, studying Hispanics in this region gives us the opportunity to study a largely Mexican population as a way to better understand the disparities in this group."


Study Methodology

The researchers retrospectively reviewed data from the Texas Cancer Registry for hematologic malignancies diagnosed in the state of Texas between 1995 and 2016, focusing on chronic and acute leukemia's (both myeloid and lymphoid), myelodysplastic syndrome (MDS), and myeloproliferative neoplasms.


Of these patients, 10,822 identified as Hispanic and 42,756 identified as non-Hispanic white. Due to low incidence in the analyzed regions, data from other races were excluded.


Survival for Hispanic and non-Hispanic whites was compared using the log-rank test and Cox regression analyses adjusting for age and diagnosis, according to the study authors. T-tests and generalized linear models were used to evaluate differences in age at diagnosis.


Key Findings

Researchers found that the age of diagnosis was significantly lower among Hispanic patients compared to non-Hispanic white patients for all blood cancers included in the analysis.


Notably, in unadjusted analyses, data showed that Hispanic patients with myeloid malignancies had better overall survival than non-Hispanic white patients, according to the study authors. There were no significant differences for patients with other types of leukemia.


However, Bencomo-Alvarez reported that, after adjusting for age, Hispanic patients with the ALL and acute promyelocytic leukemia (APL) had significantly worse overall survival rates. The 10-year survival rate for ALL patients between the ages of 18 and 49 was 28 percent among Hispanics compared to 39 percent for non-Hispanic whites, according to the study authors.


For APL patients in the same age range, 69 percent of Hispanics survived 10 years post-diagnosis versus 76 percent of non-Hispanic whites. The data showed no significant differences for other types of blood cancer.


To gain further insight on how living at the U.S./Mexico border could potentially impact survival, the researchers compared 10-year survival rates of 1,160 Hispanic patients residing in El Paso to that of 9,662 Hispanic patients living in other areas of Texas.


They observed 10-year survival rates were significantly lower for patients with ALL, AML, or chronic myeloid leukemia (CML) who lived in El Paso than for those who lived in other parts of the state (ALL: 28% vs. 31%; AML: 13% vs. 22%; CML: 43% vs. 57%).


"Living at the border correlated with worse prognosis for ALL, AML, CML, and MDS patients," said Bencomo-Alvarez. "As suspected, a worse prognosis in Hispanics correlated with lower socioeconomic status and increased numbers of comorbidities."


"Interestingly, both Hispanic and non-Hispanic patients with ALL have a worse outcome in the border region compared to the rest of Texas," he continued. "However, in acute and chronic myeloid leukemias, only Hispanic patients living near the border have a worse overall survival compared with the rest of Texas."


Ongoing work from Bencomo-Alvarez and colleagues seeks to identify potential biological factors that could impact the risk of blood cancers among Hispanics. "The ultimate goal is to improve prevention and treatment," he outlined in a press release.


Researchers acknowledged limitations of the study include that incidence and survival data about Hispanics living at the border was limited to those living in El Paso and surrounding areas, as well as the small sample size of some of subgroups.


"Hispanics are diagnosed at a significantly younger age compared to non-Hispanics," noted Bencomo-Alvarez. "Hispanic patients with ALL or APL have a worse overall survival compared with non-Hispanic whites. Hispanics with ALL, AML, CML, or MDS diagnosed near the U.S./Mexico border demonstrate worse overall survival compared with Hispanics diagnosed elsewhere in Texas.


"In general, Hispanics had more comorbidities, a general lack of health insurance, and worse socioeconomic status compared with non-Hispanics," he concluded. "Disparities in outcome caused by ethnicity is different in El Paso compared with the rest of Texas."


Catlin Nalley is a contributing writer.