Published on July 24, 2020
Acute Lymphoblastic Leukemia Crosses All Borders
Hispanics living in Texas are more likely to be diagnosed with blood cancers at an earlier age than non-Hispanic whites, particularly two types of leukemia, acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), according to a study presented in June at the virtual 2020 American Association for Cancer Research (AACR) II annual meeting.
“In general, Hispanics had more comorbidities, a lack of health insurance, and worse socioeconomic status compared with non-Hispanics,” said Dr. Alfonso E. Bencomo-Alvarez, lead study author and a postdoctoral research associate at Texas Tech University Health Sciences Center El Paso. “Disparities in outcome caused by ethnicity is different in El Paso (near the U.S./Mexico border) compared with the rest of Texas.”
Acute lymphoblastic leukemia (ALL) is a rare type of bone marrow and blood cancer. Most cases of acute lymphoblastic leukemia occur in children, but most deaths from ALL (about 4 out of 5) occur in adults, according to the American Cancer Society (ACS). ACS estimates about 6,150 new cases of ALL this year.
What Causes Racial and Ethnic Disparities in Acute Leukemia?
Hispanics comprise 18 percent of the U.S. population, a majority of which live in California, Texas and Florida. Cancer is the leading cause of death among Latino-Americans while it is the second-leading cause for whites, behind cardiovascular disease.
Among Latinos, the most common cancers are leukemias, lymphomas and brain cancers.
Dr. Bencomo-Alvarez and his team found that while Hispanics were diagnosed at an average earlier age in all the cancers studied, the starkest difference was for ALL, at an average age of 41.5 years, compared to 53.4 years for their non-Hispanic white counterparts.
In an email interview with Patient Power, Dr. Bencomo-Alvarez speculated the disparity in age at diagnosis is caused by several factors: mutations that predispose Hispanics to develop blood cancers at a younger age; living in places where there are pollutants; and work that could expose them to chemicals such as pesticides.
“Finally, social and cultural aspects may also contribute to this observation, due to the type of diet that the Hispanic community consumes, as well as low nutritional quality foods because many minority groups in the United States live in rural areas and have a low socioeconomic status,” he said.
Hispanics With Acute Lymphoblastic Leukemia Have Poorer Outcomes Compared to Whites, Study Finds
Dr. Bencomo-Alvarez and his team studied data from the Texas Cancer Registry to examine the incidence and mortality of 62,756 patients diagnosed with hematologic malignancies in the state of Texas between 1995 and 2016. The review was limited to acute and chronic leukemias, myelodysplastic syndrome (MDS), and myeloproliferative neoplasms (MPNs).
Of these patients, 10,822 (19.1%) identified as Hispanic and 42,756 (76%) as non-Hispanic white.
The most common form of hematologic malignancy among the group studied was chronic lymphocytic leukemia (CLL) — followed by AML and then MDS.
In his presentation, Dr. Bencomo-Alvarez also highlighted the disparity in overall survival rates for ALL and acute promyelocytic leukemia (APL), a type of AML in which immature white blood cells called promyelocytes accumulate in the bone marrow.
What is the Survival Rate For Hispanics with Acute Lymphoblastic Leukemia?
For patients with ALL who were between 18 and 49 years old, the 10-year survival rate of Hispanic patients was 28 percent, compared with a 39 percent 10-year survival rate in non-Hispanic whites. For patients with APL who were between 18 and 49 years old, 69 percent of Hispanic patients survived 10 years post-diagnosis compared with 76 percent of non-Hispanic white patients. No significant differences were observed for other blood cancers.
Living near the U.S./Mexico border also was associated with worse outcomes among patients with ALL, AML, chronic myeloid leukemia (CML) and MDS, he said.
Hispanic patients diagnosed with AML living in El Paso had a 10-year survival rate of 13% as opposed to 22% of those living elsewhere in the state. Regardless of race, patients with ALL living near the border showed worse outcomes than other parts of Texas.
“Hispanic individuals living at the border tend to be poorer, are more likely to lack health insurance, and many could be undocumented,” Dr. Bencomo-Alvarez said. He said this may discourage them from seeking medical care and starting treatment.
Ongoing Research and Clinical Trials
Dr. Bencomo-Alvarez told Patient Power Hispanics are an understudied group in cancer, despite being the largest and fastest-growing minority group in the U.S. While cancer health disparities have been documented in the region, the incidence and survival of blood cancer patients in Texas and at the U.S./Mexico border are unknown.
“The Texas/Chihuahua border is a medically underserved region with many financial, structural, and educational barriers for access to healthcare,” he said. “Our location in El Paso, Texas, offers a unique opportunity to study blood cancer incidence and survival in a dense Mexican American population.”
Dr. Bencomo-Alvarez said his research is ongoing. Future studies will use samples from the leukemia biobank to perform DNA and RNA sequencing to pinpoint any biological factors that might increase the risk of blood cancers in Hispanics.
“The ultimate goal is to improve prevention and treatment,” he said.
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