Abstract 4904: Say it ain’t psoas: addressing edema in pancreatic cancer body composition analyses
Authors: Evan W. Davis, Margaret A. Park, Toni L. Basinski, J. Pablo Arnoletti, Francisca Beato, Mark Bloomston, Tiffany L. Carson, Tiago Biachi de Castria, Dung-Tsa Chen, Elena M. Cortizas, Sylvia L. Crowder, Maria Genilo-Delgado, Wade G. Douglas, Kevin L. Huguet, Kun Jiang, Pamela J. Hodul, Aleksandra Karolak, Dae Won Kim, John Koomen, Anjana A. Menon, Kenneth Meredith, Qianxing Mo, Shaffer R. Mok, Lina Moreno-Urazan, Sabeen Ahmed, Nathan Parker, Jose M. Pimiento, Ghulam Rasool, Lauren M. Sparks, Paul Stewart, Alexandra F. Tassielli, Jamie K. Teer, Dan Viet Tran, Jose G. Trevino, Vic Velanovich, Xuefeng Wang, Christopher J. Whelan, Sarah M. Judge, Andrew R. Judge, Jason B. Fleming, Daniel Jeong, Jennifer B. Permuth
Journal: Cancer Research (2025)

Abstract Background: Image based body composition is the gold standard for assessing skeletal muscle area and quality in cancer patients. In patients with pancreatic ductal adenocarcinoma (PDAC), the decrease in muscle area and quality can be particularly profound. Yet image-based muscle assessment in these patients may be impeded by the presence of edema at follow up caused by disease burden and/or treatment. Edema in superficial muscle can affect the Hounsfield units of surrounding tissue leading to overestimation of muscle area. Despite this, to our knowledge no studies have examined alternative methods of assessing muscle loss in PDAC patients in the context of edema. To address this gap, we examined the prevalence of edema in PDAC patients, its impact on change in total skeletal muscle area (SMA) between diagnosis and six month follow up, and the use of psoas muscle area (pSMA), which is less impacted by edema, as an alternative method of assessing muscle loss. Methods: The study population included sixty-nine PDAC patients from the multi-center Florida Pancreas Collaborative study with serial computed tomography (CT) scans obtained at diagnosis and six month follow up. Using the CT scans, we assessed edema by identifying opacification in the subcutaneous fat defining those with opacification as edematous. We examined the prevalence of edema at six-month follow up in the overall PDAC population and tested for differences by race and sex using Fisher’s Exact test. SMA and pSMA were quantified as surface area (cm2) at L3 with sliceOmatic software. SMA and pSMA percent change and mean change between diagnosis and follow up were calculated in the overall population and by edema status at follow up. Spearman correlation was used to test the interrelationship of SMA and pSMA according to edema status. Results: Prevalence of edema at follow up was 53.6% and did not significantly differ by race (p&amp;gt;0.76) or sex (p&amp;gt;0.05). In the overall population, SMA increased by 0.472% between diagnosis and follow up. When stratified by edema status, SMA increased in patients with edema (+3.06%) whereas SMA in patients without edema decreased (-2.52%). Conversely, pSMA decreased by 6.32% and this was consistent across edema status (-5.69% for present and -7.05% for absent). Finally, we observed that SMA and pSMA at follow up are strongly correlated in both the presence (r=0.72) and absence of edema (r=0.77). Conclusions: In this study, we observed that edema is prevalent in most PDAC patients at follow up contributing to an overestimation of SMA. This overestimation may introduce bias into understanding the impact of PDAC on muscle wasting, an important factor in cancer cachexia. Encouragingly, findings suggest pSMA may be a suitable proxy for total SMA and limit the impact of edema on SMA estimates. These findings have important implications for enhancing our understanding of muscle changes over the PDAC cancer care continuum and should be considered in future studies. Citation Format: Evan W. Davis, Margaret A. Park, Toni L. Basinski, J. Pablo Arnoletti, Francisca Beato, Mark Bloomston, Tiffany L. Carson, Tiago Biachi de Castria, Dung-Tsa Chen, Elena M. Cortizas, Sylvia L. Crowder, Maria Genilo-Delgado, Wade G. Douglas, Kevin L. Huguet, Kun Jiang, Pamela J. Hodul, Aleksandra Karolak, Dae Won Kim, John Koomen, Anjana A. Menon, Kenneth Meredith, Qianxing Mo, Shaffer R. Mok, Lina Moreno-Urazan, Sabeen Ahmed, Nathan Parker, Jose M. Pimiento, Ghulam Rasool, Lauren M. Sparks, Paul Stewart, Alexandra F. Tassielli, Jamie K. Teer, Dan Viet Tran, Jose G. Trevino, Vic Velanovich, Xuefeng Wang, Christopher J. Whelan, Sarah M. Judge, Andrew R. Judge, Jason B. Fleming, Daniel Jeong, Jennifer B. Permuth, on behalf of the Florida Pancreas Collaborative. Say it ain’t psoas: addressing edema in pancreatic cancer body composition analyses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4904.