ESTRO 2025 - Abstract Book

S1152

Clinical – Lower GI

ESTRO 2025

Seven of the twelve patients were alive and free from any progression at more than five years after randomisation, three of whom had received repeat MDT but no systemic therapy. Actuarial OS at 5 years was 67% (95%CI, 45-99).

All patients with polymetastatic progression subsequently died. Polymetastatic-PFS (pPFS) at 5 years was 58% (95%CI, 36-94). pPFS (p=0.0007), but not PFS (p=0.2), was correlated with OS. QoL was not different between arms.

Conclusion: Despite low numbers, SABR seems to reverse progression of oligometastatic CRC without systemic therapy and entail long-term survival, but repeat MDT of all new oligometastatic lesions seems to be required. pPFS significantly correlated with OS and may be a preferable surrogate endpoint for OS compared with PFS when studying the contribution of MDT to survival in LOM.

Keywords: colorectal, stereotactic, lung oligometastases

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Digital Poster Impact of glutamine-peptide-formula on acute-toxicity-symptoms in rectal-cancer neoadjuvant Chemo radiotherapy treatment Barbara Gabriela Salas-Salas 1 , Laura Ferrera-Alayón 1 , Alicia Calleja-Fernández 2 , Antonio Alayón-Afonso 1 , Anais Ramos-Ortiz 1 , Rodolfo Chicas-Sett 3 , Eva Nogués-Ramia 4 , Juan Zafra-Martín 5 , Marta Lloret 1 1 Radiation Oncology, University Hospital Dr Negrín, Las Palmas de Gran Canaria, Spain. 2 Medical Department, Adventia Pharma, Las Palmas de Gran Canaria, Spain. 3 Radiation Oncology, ASCIRES GRUPO BIOMÉDICO, Valencia, Spain. 4 General Surgery, University Hospital Dr Negrín, Las Palmas de Gran Canaria, Spain. 5 Radiation Oncology, Hospital Universitario Virgen de la Victoria, Malaga, Spain Purpose/Objective: Rectal cancer patients can develop gastrointestinal toxicity from chemoradiotherapy, affecting their clinical, functional, and nutritional progression. This study aimed to assess the effectiveness of dietary advice plus glutamine-enriched peptide diet (PD) compared to exclusive dietary advice (DA) on gastrointestinal acute toxicity (GAT), treatment interruptions, and nutritional outcomes in rectal cancer patients undergoing neoadjuvant therapy.