Obesity associated with improved immunotherapy outcomes among certain patients with cancer
Obesity appeared associated with improved immunotherapy outcomes among patients with certain cancer types, according to a cohort study published in JAMA Network Open.
“The benefits of obesity in patients treated with immune checkpoint blockade and the underlying mechanisms are being examined, but the scale and spectrum of benefit across cancer types is unknown,” Timothy A. Chan, MD, PhD, director of the Center for Immunotherapy and Precision Immuno-Oncology at Cleveland Clinic's Lerner Research Institute, and colleagues wrote.
Background and methodology
Chan and colleagues initiated the research to improve understanding of the obesity paradox: that obesity is both a risk factor for cancer but also may be associated with improved treatment outcomes.
They evaluated pretreatment BMI of 1,840 patients (median age, 63.84 years; range, 55.66-71.16; 57.55% men) who received at least one dose of immune checkpoint blockade treatment between 2014 and 2019. Among the 16 cancer types represented in the cohort, the most common included non-small cell lung cancer (n = 639), renal cancer (n = 220) and melanoma (n = 209).
Chan and colleagues measured BMI within 30 days before treatment. They defined normal weight (BMI, 18.5 kg/m2 to 24.9 kg/m2), overweight (BMI, 25 kg/m2 to 29.9 kg/m2) and obesity (BMI, 30 kg/m2) according to WHO guidelines.
Results of pancancer survival analyses showed patients with obesity had longer OS after immune checkpoint blockade treatment than patients with overweight (HR = 0.82; 95% CI, 0.7-0.96) or normal weight (HR = 0.67; 95% CI, 0.57-0.78).
Researchers also observed longer OS following immune checkpoint blockade treatment among patients with overweight vs. normal weight (HR = 0.81; 95% CI, 0.71-0.93).
In addition, patients with obesity had longer PFS than patients with overweight (HR = 0.89; 95% CI, 0.78-1.02) or normal weight (HR = 0.77; 95% CI, 0.68-0.87), and patients with overweight had longer PFS than patients with normal weight (HR = 0.86; 95% CI, 0.76-0.97).
Obesity also appeared associated with higher radiographic response rates vs. normal weight or overweight.
Study limitations included small statistical power in subgroup analyses because of sample sizes and that the study did not address cancer type-specific confounding variables, including International Metastatic Renal Cell Carcinoma Database Consortium risk score.
“Therefore, the results in some cancer types warrant further study with larger cohorts to address specific confounding variables in more detail,” the researchers wrote. “In addition, BMI is not a perfect assessment of obesity because it cannot distinguish muscle from body fat. Hence, body fat measurement methods such as dual-energy X-ray absorptiometry may have value in future studies.”