• Posted July 12, 2023

Obesity, Overweight Shrinks Survival Rates Against Childhood Leukemia

A growing obesity epidemic may affect the outcome of treatment for those dealing with cancer, according to a new study of adults and teens being treated for acute lymphoblastic leukemia (ALL).

Researchers called for further study of how weight affects the response to different chemotherapy regimens for ALL.

"We have known for roughly 15 years that obesity affects survival in pediatric patients treated for ALL, and more recently, we are recognizing a similar relationship in adult populations,"said lead author Dr. Shai Shimony, an advanced fellow at the Dana-Farber Cancer Institute in Boston. "But we wanted more granular data on this, to understand why this correlation exists, and how dependent it is on age."

For the study, Shimony's team collected data on 388 individuals (average age, 24 years) who were treated on Dana-Farber Consortium pediatric regimens for ALL from 2008 to 2021. The investigators examined the relationship between body mass index (BMI, a measure of body fat based on height and weight); age; toxicities; and treatment outcomes.

In all, nearly 47% of the individuals were overweight or obese. The study found they had a higher rate of non-relapse death, nearly 12%, compared to just under 3% for those with a normal BMI. They also had a lower event-free survival rate -- 63% versus 77% at four years. (Event-free survival is the length of time after treatment that the patient is free of complications.)

These patients also had worse survival overall, 64% versus 83%, compared to those with normal BMIs, according to the report published July 11 in the journal Blood Advances.

The investigators found equivalent survival among younger patients (aged 15 to 29) and older patients (aged 30 to 50) whose BMI was normal -- 83% compared to 85%. The study authors called that incredibly important because age is often considered a negative in ALL prognosis.

The main factor driving worse outcomes overall was not disease relapse but death without a relapse, the researchers noted.

Elevated liver enzymes and blood sugar levels were more common in patients who were overweight or obese -- about 61% versus 42% for liver enzymes, and 36% versus 24% for blood sugar.

Overall, higher BMI was associated with worse survival, and age was not associated with survival.

Surprisingly, elevated triglycerides (fats in the bloodstream) were associated with improved survival. The researchers noted that these were due to one of the principal chemotherapy medications included in the regimen. They said this suggests it may be possible to use this affordable lab test as a biomarker of treatment effectiveness, and it should not be seen as an adverse finding.

The study authors also noted the effectiveness of the treatment regimen in 18- to 50-year-old patients with normal BMI.

They said BMI, waist size and waist-to-hip ratio should be collected in preparation for treatment and correlated with outcomes.

"Moving forward, we hope that measures of obesity will be considered a vital variable in determining the most suitable treatment regimens for each individual patient," Shimony said in a journal news release.

More information

The American Cancer Society has more on acute lymphoblastic leukemia.

SOURCE: Blood Advances, news release, July 11, 2023