Characterization of Body Composition Dynamics Throughout Treatment in Patients with Early-Stage Breast Cancer

Abstract This study characterized computed tomography (CT)-derived body composition and tissue morphology in females with non-metastatic breast cancer (BC), both cross-sectionally (n = 56) and longitudinally (n = 38), with comparative evaluations against healthy controls and cachexia-prone females with lung cancer. Despite relative weight stability, BC patients demonstrated significant declines in skeletal muscle quality and increases in subcutaneous adipose attenuation. Morphologic changes occurred even in the absence of pronounced muscle loss, namely through reductions in lean tissue masked by concurrent increases in intra-compartmental adipose. Longitudinal interactions suggest divergent phenotypes such that non-cachectic patients demonstrated subtle, though measurable, remodeling of stable muscle quantity, whereas wasting of both muscle and adipose quantities and remodeling of externally deposited adipose was characteristic of cachexia. Findings highlight the discordance between weight loss and underlying tissue morphology and suggest that conventional cachexia criteria may under-detect clinically relevant remodeling in early-stage BC. CT-based assessments may improve phenotyping and better inform supportive care strategies across cancer populations. Competing Interest Statement The authors have declared no competing interest. Funding Statement This research was supported by the National Institutes of Arthritis, Musculoskeletal and Skin Diseases (NIAMS) under award number R01AR079445 (Pistilli). Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The source data were openly available to the public before the initiation of the study. Data were accessed in The Cancer Imaging Archive at: https://www.cancerimagingarchive.net/collection/acrin-flt-breast/; https://www.cancerimagingarchive.net/ collection/acrin-nsclc-fdg-pet/; https://www.cancerimagingarchive.net/collection/healthy-total-body-cts/ I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability Statement The datasets analyzed in the current study are available with open-access from The Cancer Imaging Archive, [https://www.cancerimagingarchive.net/collection/acrin-flt-breast/; https://www.cancerimagingarchive.net/collection/acrin-nsclc-fdg-pet/; https://www.cancerimagingarchive.net/collection/healthy-total-body-cts/].