Obese youths with acute lymphoblastic leukemia (ALL) are known to have worse outcomes than their lean counterparts.
To gain more insight into this phenomenon, investigators set out to determine if body mass index (BMI) impacted ALL patients’ responses to initial chemotherapy.
The results showed that, following induction chemotherapy, obese patients were more than twice as likely to have minimal residual disease (MRD) than non-obese patients.
“Induction chemotherapy provides a patient’s best chance for remission or a cure,” said principal investigator Steven Mittelman, MD, PhD, of The Saban Research Institute of Children’s Hospital Los Angeles in California.
“Our findings indicate that a patient’s obesity negatively impacts the ability of chemotherapy to kill leukemia cells, reducing the odds of survival.”
The study, which was published in Blood, included 198 patients who were diagnosed with ALL and between the ages of 1 and 21 years.
Each patient’s BMI was converted to a percentile and classified according to the Center for Disease Control and Prevention’s thresholds for overweight (85% to 94%) and obese (greater than 95%). Patients with a BMI less than 85% were considered “lean.”
About one-third of the patients were obese or overweight at the time of diagnosis.
MRD was determined by testing bone marrow specimens at the end of induction therapy, and patients were followed for 2 to 5 years from the time of diagnosis.
The investigators found that lean patients with MRD had similar outcomes to obese patients without evidence of MRD. Obese patients with MRD had the worst outcomes.
Additionally, although nearly a quarter of the patients initially deemed “lean” gained weight and became obese during the first month of treatment, these patients still showed similar outcomes to those who remained lean.
“In addition to increasing a patient’s likelihood of having persistent disease following treatment, obesity appears to add a risk factor that changes the interaction between chemotherapy and residual leukemia cells,” said Hisham Abdel-Azim, MD, also of The Saban Research Institute.
Findings from this study offer new avenues for investigation that include modifying chemotherapy regimens for obese patients and working to change a patient’s weight status beginning at the time of diagnosis.
