Disparities Seen in Hematologic Cancer Incidence and Survival for Hispanic Patients in Texas

Alfonso E. Bencomo-Alvarez, PhD

Disparities were seen in terms of the incidence and survival of hematologic malignancies for Hispanic versus non-Hispanic white patients living in Texas and near the US/Mexico border, according to the results of a population study analysis presented in a press program ahead of the American Association for Cancer Research (AACR) Virtual Annual Meeting II.¹

“Hispanics are diagnosed at a significantly younger age compared with non-Hispanics, [and] Hispanic patients with acute lymphoblastic leukemia [ALL] and acute promyelocytic leukemia [APL] have a worse overall survival compared with non-Hispanics,” said Alfonso E. Bencomo-Alvarez, PhD, when presenting the findings during the press program. Bencomo-Alvarez is a postdoctoral research associate in the laboratory of Anna Eiring, PhD, at Texas Tech University Health Sciences Center El Paso. “In general, Hispanics had more comorbidities, a lack of health insurance, and worse socioeconomic status compared with non-Hispanics.”

Hispanics represent the largest and fastest-growing minority group in the United States, accounting for 18% of the total population. A majority of Hispanics live in Southern states including primarily California and Texas. Cancer is the leading cause of death for Hispanic-Americans in the United States, yet it is the second highest cause of death among non-Hispanic whites.²

The most common cancer types among Hispanic patients are leukemias, lymphomas, and brain cancers. Leukemias specifically are found to have a higher prevalence among Hispanic children and adolescents, and adult Hispanic patients with other leukemias have been known to be diagnosed at younger ages and typically have a worse prognosis than other patients. However, the rate of incidence and survival for patients with hematologic malignancies in a dense Mexican-American population were unknown prior to this study.

The investigators looked at patient data from the Texas Cancer Registry to examine incidence and mortality rates from patients diagnosed with hematologic malignancies in Texas between 1995 and 2016. The malignancies examined were narrowed to acute and chronic leukemias, myelodysplastic syndrome (MDS), and myeloproliferative neoplasms (MPNs).¹

A total of 62,753 cases were identified with available ethnicity data. After excluding cases with insufficient data and patients with MDS diagnosed prior to 2005, a total of 56,525 cases were selected, with 10,822 (19.1%) of these patients identifying as Hispanic and 42,756 as non-Hispanic white.

The most prevalent malignancy was chronic lymphocytic leukemia (CLL) in 18,296 total patients, followed by acute myeloid leukemia (AML) in 12,807, and MDS in 10,875 patients.

Differences in overall survival (OS) and the age at diagnosis were analyzed between the Hispanic and non-Hispanic white patient populations.

Across all of the analyzed disease types, Hispanic patients in Texas were diagnosed at significantly younger ages than non-Hispanic patients. The most significant difference was seen with ALL, where the average age for Hispanic patients was 41.5 years (standard derivation [SD], ±18.19) compared with 53.4 years (SD, ±20.28) for non-Hispanic patients (P <.0001).

The risk of developing a hematologic malignancy was mostly similar for Hispanic and non-Hispanic patients. However, Hispanic patients had a higher incidence of blood cancers in younger patients 40 years or younger and non-Hispanic patients had a higher incidence of blood cancers in older patients older than 40 years.

Multivariate analyses showed that Hispanic ethnicity was correlated with worse outcomes for patients with ALL (HR, 1.23; P <.0001) and APL (HR, 1.28; P <.0001). Living near the US/Mexico border was also correlated with worse outcomes among patients with ALL, AML, chronic myeloid leukemia (CML), and MDS. Additionally, worse prognoses for Hispanic patients was correlated with lower socioeconomic status and an increase in comorbidities.

Hispanic ethnicity was associated with worse OS outcomes for patients under 70 years with ALL and for patients under 50 years with APL. For patients aged 18 to 49 with APL, the 10-year OS rate for Hispanic patients was 69% compared with 76% among non-Hispanic patients (P <.05). At ages 50 to 69 years, the 10-year OS rates were 43% and 48% for Hispanic and non-Hispanic patients with APL, respectively.

Living in El Paso near the US/Mexico border also correlated with worse OS outcomes for Hispanic patients, especially for patients with AML or CML.

“It is important to highlight that El Paso, Texas, located in health service region number 10, is considered a medically underserved region, with many…barriers to obtain health care locally among the Hispanic population,” Bencomo-Alvarez commented.

In Hispanic patients with AML, those living in El Paso showed a 10-year survival probability rate of 13% compared with 22% for those living elsewhere in the state (P <.0001). Hispanic patients with CML living at the border had a 10-year survival probability of 43% versus 57% for those outside of El Paso (P <.0001). Patients with ALL living near the border showed worse outcomes regardless of ethnicity.

“[This] report on the diagnosis of blood cancers in the US/Mexico border inure the different frequency of leukemia subtypes and their outcomes, highlighting important health disparities due to different access to diagnosis and care due to a series of factors,” said moderator Antoni Ribas, MD, PhD, FAACR, chairperson of the AACR Annual Meeting 2020 Program and AACR president, when commenting on the results. Ribas is a professor of medicine, surgery, and molecular and medical pharmacology at the University of California, Los Angeles.

_References

_{1. Bencomo AE, Rubio AJ, Gonzalez MA, et al. Retrospective study of incidence and survival for patients with hematological malignancies residing at the U.S./Mexico border. Presented at: 2020 American Association for Cancer Research Virtual Annual Meeting II; June 22-24, 2020.}

_{2. Cancer Facts & Figures for Hispanics/Latinos 2018-2020. American Cancer Society. 2018. Accessed June 19, 2020. https://bit.ly/3eki7f1}