Body Mass Index and Clinical Associations in Australasian Lymphoma Patients: A Lymphoma and Related Diseases Registry Study

Abstract

Introduction: Overweight and obesity are increasing rapidly in most countries. Underweight body mass index (BMI), though much less common, is also associated with adverse health outcomes. There is poor understanding of the implications of BMI in lymphoma patients. Recent international guidelines indicate that curative-intent cancer treatment should not be modified for obesity alone, with no specific recommendations for low BMI patients. Our aim was to examine the impact of BMI on outcomes in a contemporary cohort of lymphoma patients. Method(s): We examined BMI in relation to baseline clinical features and outcomes in an Australasian cohort of 4686 lymphoma cases from the national registry. Result(s): Patients with an overweight or obese BMI had no significant decrement in overall survival (OS) or progression free survival (PFS) compared to those with a normal BMI for any of the histological subtypes examined in this study. However, the minority of patients with underweight BMI demonstrated inferior OS for Hodgkin lymphoma (adjHR = 2.55, 95% CI = 1.05-6.19, p = 0.04) and OS (adjHR = 1.54, 95% CI = 1.02-2.32, p = 0.04) in diffuse large B-cell lymphoma compared to patients with a normal BMI. Conclusion(s): These findings support continued standard dosing in overweight and obese patients and identify poor outcomes requiring careful management in underweight populations. Trial Registration: The authors have confirmed clinical trial registration is not needed for this submission. Copyright © 2026 The Author(s). eJHaem published by British Society for Haematology and John Wiley & Sons Ltd.