• A study of over 500,000 lung cancer patients reveals that BMI affects mortality risk differently in immunotherapy versus chemotherapy.
• For NSCLC patients with a BMI under 28, immunotherapy was associated with lower mortality compared to chemotherapy.
• In patients with a BMI of 28 or higher, chemotherapy showed a continued decrease in mortality risk, while immunotherapy's risk increased.
• Findings suggest BMI should be considered when selecting treatment for advanced non-small cell lung cancer.