Acute lymphoblastic leukemia ALL-L2 blood smear under light microscopy
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A retrospective survival analysis conducted by researchers at Baylor College of Medicine and Texas Children’s Hospital found that children with acute lymphoblastic leukemia (ALL) who lived along the Texas border with Mexico were more likely to die within five years than those living in other areas of the state. The findings, published by Wiley online in CANCER, a peer-reviewed journal of the American Cancer Society highlight the health disparities in these regions which are typically underserved.

“The Texas-Mexico border comprises approximately one half of the entire US-Mexico border region and is characterized by unique demographics, with >80% of the population reporting Hispanic ethnicity,” the researchers wrote. “This region is both economically disadvantaged and medically underserved. With as many as three million inhabitants along the Texas-Mexico border, up to 29.3% of this population lives in poverty compared with 15.9% in the rest of the state.” The investigators noted that survival disparities in this region have been documented for adults with cervical, liver, colorectal and hematologic malignancies have been documented previously, it was unknown whether these disparities also affected children living along the border.

For the purposes of the study, the investigators used the definition of the border as defined in the La Paz Agreement of 1986, which defined it as the region that extends 100 km north and south of the Rio Grande River. Under this definition, 32 Texas counties are considered to be border counties while 222 counties are nonborder counties. The Texas cities of El Paso, Laredo, and McAllen are all located in the border area.

The analysis comprised information of children with both ALL and acute myeloid leukemia (AML) found in the Texas Cancer Registry. In all, between 1995 and 2017 6,002 children in the state were diagnosed with ALL and another 1,279 with AML. Of the children with ALL the analysis showed a lower percentage of children form the border areas who survived at least five years (77.5%) compared with the children who live in other parts of the state, 85.8% of whom lived at least five years.

When adjusting for other factors known to affect survival rates including socioeconomic status, age at diagnosis, and sex, the investigators determined that children residing along the Mexico border had a 30% higher risk of death compared with their non-border dwelling peers. For children with AML, there was an increased risk of death only for those living in rural border counties.

The researchers used Cox proportional hazards models to evaluate the factors associated with the risk of death, while overall survival estimates were calculated using Kaplan–Meier methods.

“While there have been tremendous achievements in maximizing cure rates for children with leukemia in the United States, not everyone is benefiting from these advances. We know there are differences in survival, with children from historically marginalized Hispanic and Black communities faring worse than white children,” said Castellanos. “There is an urgent need to identify the reasons why these differences in survival are occurring, including an assessment of the barriers to obtaining health care and strategies to successfully reduce barriers.”

Paula Aristizabal, MD, and colleagues from the University of California San Diego in an editorial accompanying the analysis encouraged efforts to improve cancer outcomes in rural communities and those with high-than-average rates of poverty. “We urgently call for the attention of public health leaders and healthcare providers in both the U.S. and Mexico to mitigate the health disparities suffered by immigrants, a population that plays a vital role for the economies and social fabric of these two countries,” they noted.

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