ESTRO 2025 - Abstract Book

S1229

Clinical – Lower GI

ESTRO 2025

Conclusion: SBRT delays subsequent chemotherapy, regardless of when it is administered, at least for 9 months. Better outcomes were observed with a BED ≥100 Gy 10 and in patients with lung metastases. These results support SBRT as an effective strategy for managing oligometastatic mCRC, improving local control and treatment sequencing.

Keywords: SBRT, Colorectal Cancer, Oligometastatic desease

3118

Digital Poster How predict complete response after definitive chemoradiotherapy for locally advanced SCC of the anal canal: the role of sequential PET/CT imaging Marianna Valzano 1 , Elisabetta Abenavoli 2 , Mauro Loi 1 , Michele Aquilano 3 , Pierluigi Bonomo 1 , Alessandra Galardi 1 , Carlotta Becherini 1 , Emanuela Olmetto 1 , Vieri Scotti 1 , Icro Meattini 1 , Isacco Desideri 1 , Vanessa Di Cataldo 1 , Marco Banini 1 , Andrea Romei 1 , Carolina Orsatti 1 , Ilaria Bonaparte 1 , Luca Burchini 1 , Cecilia Petruccioli 1 , Vittorio Briganti 2 , Valentina Berti 2 , Lorenzo Livi 1 1 Radiation Oncology,, Azienda Ospedaliero Universitaria Careggi, University of Florence, Florence, Italy. 2 Nuclear Medicine Unit, Azienda Ospedaliero Universitaria Careggi, University of Florence,, Florence, Italy. 3 CyberKnife Center, Istituto Fiorentino di Cura e Assistenza (IFCA), Florence, Italy Purpose/Objective: The standard treatment for locally advanced squamous cell carcinoma of the anal canal (SCCAC) is definitive radiotherapy (RT) with concurrent chemotherapy (CRT), with excellent outcomes. Nevertheless, rates of locoregional failure of 10% to 30% have been reported. Defining a surveillance strategy after radical CRT is essential: is necessary to identify the diagnostic test and the appropriate timing to evaluate the response to CRT and assess the need for timely salvage surgery. The aim of this study is to evaluate the effectiveness of follow-up MR and 18-FDG PET/CT to predict response to CRT in patients with SCCAC.