ESTRO 2024 - Abstract Book

S1501

Clinical - Lower GI

ESTRO 2024

We describe NAT-resistance in patients with VFA/SFA ratio ≥0.4, which in turn associates with elevated circulating markers of SIR. There are recognised structural and functional differences between VF and SF, with the former considered to be more pro-inflammatory and contributes to a greater degree of metabolic derangements (12, 18). We propose that the increased levels of VF in comparison to SF drives a pro-inflammatory environment, which in turn favours tumourigenesis and NAT resistance through a number of possible pathways. Changes in BCp during or as a result of NAT have been witnessed in other cancer subtypes but there is limited study in LARC (14, 19, 20). In our study, there was no significant change when comparing pre- to post-NAT BCp. Longitudinal changes to BCp in colorectal cancer have been witnessed over a 1 year period (15), however this is not reflected in the short time period between staging and re-staging scans. We conclude that NAT in LARC does not significantly affect patients’ BCp prior to surgery. Longer term follow-up with surveillance in post-operative and sustained cCR patients is required to fully understand this. Considering the increasing prevalence of obesity, a greater understanding of its role in LARC is required. As BCp measurements can now be performed with automated software, they could aid in the identification of patients at risk of incomplete response. Some studies are already attempting to influence BCp to achieve greater cCR (21). Future studies should focus on how BCp could influence future NAT regimes and ultimately increase organ preservation in LARC.

Keywords: Rectal, Cancer, Body-composition

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