A High BMI Could Help Cancer Immunotherapy Patients

There is a mountain of evidence to support that a high body mass index (BMI) and obesity negatively impact cancers, diabetes, cardiovascular, and other diseases. Yet, for every “rule” there is always an exception and investigators at Flinders University in South Australia, have found that in some cases a high BMI may actually improve the chance of survival among certain cancers. Focusing on clinical trials of atezolizumab, a common immunotherapy treatment for non-small-cell lung cancer (NSCLC), the research team found improved responsiveness to the drug in those with a high BMI.

Findings from the new study were published recently in JAMA Oncology through an article titled “Association between body mass index (BMI) and overall survival with immune checkpoint inhibitor therapy for advanced non-small-cell lung cancer: Analysis of atezolizumab clinical trials.”

“This is an interesting outcome and it raises the potential to investigate further with other cancers and other anticancer drugs,” noted lead study investigator Ganessan Kichenadasse, MD, a medical oncology researcher at the Flinders Centre for Innovation in Cancer. “We need to do further studies into the possible link between BMI and related inflammation, which might help to understand the mechanisms behind the paradoxical response to this form of cancer treatment.”

The WHO estimates at least 2.8 million people die each year as a result of being overweight or obese. Overweight and obesity lead to adverse metabolic effects on blood pressure, cholesterol, triglycerides, and insulin resistance. Risks of coronary heart disease, ischemic stroke, and type 2 diabetes mellitus increase steadily with increasing BMI, a measure of weight relative to height.

The Flinders researchers found that NSCLC patients with high BMI (25 kg/m²) in four clinical trials had a significant reduction in mortality with atezolizumab, apparently benefiting from immune checkpoint inhibitor (ICI) therapy. Treatment options for this form of lung cancer are rapidly evolving and include ICIs, molecular targeted drugs, and chemotherapies.

“Previous studies have explored a concept called as ‘obesity paradox’ where obesity is associated with increased risks for developing certain cancers and, counter-intuitively, may protect and give greater survival benefits in certain individuals,” noted Kichenadasse. “Our study provides new evidence to support the hypothesis that high BMI and obesity may be associated with response to immunotherapy.”

Of the 1,434 participants studied in the Australian research, 49% were normal weight, 34% were overweight, and 7% were obese.

“While our study only looked at baseline and during treatment, we believe it warrants more studies into the potentially protective role of high BMI in other cancer treatments,” Kichenadasse concluded.