ESTRO 2025 - Abstract Book

S1807

Clinical – Upper GI

ESTRO 2025

Table 2 outlines the dosimetric characteristics of the treated lesions. Patient A and B achieved a complete response but subsequently relapsed distally. Patient C achieved partial response at 3 months and patient D has not yet reached the time point for follow up.

The only reported acute toxicity was Grade 1 fatigue. Three patients had FBP before, during and after treatment. There were not acute changes in FBP values. Patient B developed lymphopenia at 5 months without infection. No other late toxicities have been documented. Conclusion: We report the first experience of MRgRT for splenic metastasis to date. Our experience suggests that MRgRT provides non-invasive, reasonable disease control with an acceptable toxicity profile.

Keywords: Spleen, MRgRT, oligometastatic

References:

(1) Sauer J, et al. Splenic metastases—not a frequent problem, but an underestimated location of metastases: epidemiology and course. J Cancer Res Clin Oncol. 2009 May;135(5):667-71. doi: 10.1007/s00432-008-0502-3. Epub 2008 Oct 21. (2) Palma DA, et al. Stereotactic ablative radiotherapy versus standard of care palliative treatment in patients with oligometastatic cancers (SABR-COMET): a randomised, phase 2, open-label trial. Lancet. 2019;393(10185):2051-8. (3) De Leon J, et al. Analysis of data to advance personalised therapy with MR-Linac (ADAPT-MRL). Clinton Transl Radiat Oncol. 2021 Nov;31:64-70. doi: 10.1016/j.ctro.2021.09.004. (4) Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0. 2017.

2641

Proffered Paper Treatment of cN3M0 esophageal cancer: a nationwide study using propensity score matching Charlotte JH Hafkamp 1 , Elisabeth D Geijsen 1 , Hanneke WM van Laarhoven 2 , Sarah Derks 2 , Roel J Bennink 3 , Rob HA Verhoeven 2,4 , Suzanne S Gisbertz 5 , Mark I van Berge Henegouwen 5 , Pim B Olthof 6 , Arjen van der Veen 7 , Peter SN van Rossum 1 1 Radiation Oncology, Amsterdam University Medical Center, Amsterdam, Netherlands. 2 Medical Oncology, Amsterdam University Medical Center, Amsterdam, Netherlands. 3 Radiology and Nuclear Medicine, Amsterdam University Medical Center, Amsterdam, Netherlands. 4 Research and Development, Netherlands Comprehensive Cancer Organization (IKNL), Utrecht, Netherlands. 5 Surgery, Amsterdam University Medical Center, Amsterdam, Netherlands. 6 Surgery, University Hospital Antwerp, Antwerp, Belgium. 7 Radiation Oncology, University Medical Center Utrecht, Utrecht, Netherlands

Purpose/Objective: Esophageal cancer with stage cTanyN3M0 has a poor prognosis, due to a high risk of distant recurrence. Few