Residence predictor of survival among Black, Hispanic patients with acute myeloid leukemia
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Black and Hispanic patients with acute myeloid leukemia who resided in socially disadvantaged neighborhoods had a significantly greater risk for mortality than their white counterparts, according to study results published in Blood.
Rationale and methods
“The current study was a foray into understanding and documenting the gaps in leukemia care delivery and was inspired by the collective experiences of leukemia faculty representing major Chicago academic centers who saw firsthand that the rapidly burgeoning field of precision oncology was not benefiting all patients with leukemia,” Irum Khan, MD, MS, associate professor of hematology/oncology at University of Illinois College of Medicine, told Healio.
One of Khan’s experiences involved a young woman referred to her from a rural clinic several hours away for “abnormal blood counts.”
“The labs she had brought were months old and mildly abnormal. Unfortunately, her insurance did not permit me to do any testing at our site and she was very worried about incurring any expenses. I called her referring physician and recommended urgent labs the next morning,” Khan said. “I had a nagging feeling that something was amiss but since nothing concrete emerged on physical exam and she needed to return to young children and did not want to go to the emergency room, I let her return home with her parents.
When Khan called the next day to follow up on the woman, he was told she died the night before in the shower.
“No postmortem was done and her cause of death will forever be an unanswered question,” she said. “At its core, this represented a failure of our medical system by crippling a physician’s potential to intervene and possibly change an outcome.”
The experience and others led Khan and colleagues to examine the interaction of clinical and disease-specific factors with data on neighborhood segregation levels among patients with AML. The discreet survival analysis included 822 adults (54.1% men) with AML diagnosed between 2012 and 2018 across six Chicago-area cancer centers. Researchers pooled data on patient’s sex, race or ethnicity, age at diagnosis, coexisting health conditions, health insurance status and genomic cancer features to assess better or worse survival outcome. They additionally gathered U.S. Census data on patients’ neighborhoods of residence and grouped the neighborhoods according to their level of segregation, affluence or disadvantage.
Key findings
Overall, 497 patients self-identified as white, 126 as Black, 117 as Hispanic and 82 as other or unknown race.
Results showed both Black (HR = 1.59; 95% CI, 1.15-2.22) and Hispanic (HR = 1.25; 95% CI, 0.88-1.79) patients experienced inferior survival outcomes compared with white patients.
Black and Hispanic patients also had a higher likelihood of residing in segregated, socially disadvantaged neighborhoods.
“Where a patient lives is a stronger driver of inferior survival among Black and Hispanic patients with AML vs. the mutations in their tumor. When we eliminate the influence of a patient's census tract, the leukemia death difference between Black and white patients with AML decreased from 58% to 11%. Therefore, it is not accurate to assume mutations alone predict disease outcome,” Khan said.
Researchers also found higher rates of treatment complications among Hispanic patients (30%) and Black patients (27%) compared with white patients (22%), and that Black patients had a lower likelihood of undergoing stem cell transplantation than Hispanic and white patients.
Implications
“Our study documented quantitatively what we all suspected and were seeing in our silos. We have seen social factors play out every day — from the patient who was at the completion of therapy of favorable-risk leukemia and died in septic shock waiting for his girlfriend to take him to the hospital after finishing third shift, to the elderly woman trying to keep all her appointments for an early-phase clinical trial while being the sole custodian of her school-age grandson who was a victim of child abuse,” Khan said.
However, she found the extent to which the census tract mediated outcomes and how much it outstripped mutation profile in driving survival disparities eye-opening and highlighted the true magnitude of the problem.
“The rapidly increasing adoption of low-intensity molecularly targeted outpatient regimens for AML make it incumbent upon us to acknowledge and address structural barriers to effective and safe therapy. Ironically, this includes unequal access to next-generation molecular sequencing, which was missing in nearly half of the patients in our cohort,” Khan said. “We must invest resources to better understand and prioritize the structural factors that govern outcomes so strongly that they outcompete cutting-edge genomic technologies.
“This study is a call to action for investigations into determinants of treatment response and toxicity through the lens of structural racism,” Khan added. “This could include improved pretreatment risk stratification to minimize toxicity, pharmacodynamic and pharmacokinetic studies in ethnoracially diverse populations, assessment of minimal residual disease, and initiatives to increase enrollment of underrepresented minorities in clinical and biobanking trials.”
Irum Khan, MD, MS, can be reached at University of Illinois Hospital and Health Sciences System, 840 S. Wood St., 820-E CSB, Chicago, IL 60612; email: irumkhan@uic.edu.
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