ESTRO 2023 - Abstract Book

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ESTRO 2023

Figure 1. Delineations of five observers on sagital CT with co-registered MR sequences.

Results In the preliminary analysis we included the first thirteen patients, seven had the tumor in the proximal third of the esophagus, one in the middle and five in the distal third. The analysis showed the smallest mean GTV volume when contoured on MR alone (39.2cm3) and the largest on PET CT alone (54.9 cm3). We observed the best agreement when contouring on all three imaging modalities (CIgen 0.69), the worst agreement on CT and MR alone, CIgen 0.61 for both (table 1).

Table 1. Volume of GTV and CIgen per case and modality.

The addition of MR to PET CT reduced inter-observer variation more in patients with tumors of the distal third (CIgen 0.59) in comparison to PET CT alone (CIgen 0.54), than in patients with tumors of the proximal or middle third with CIgen 0.75 on all three imaging modalities and CIgen 0.73 on PET CT alone. Conclusion Our preliminary analysis showed the highest agreement in contouring the GTV in esophageal cancer on all three imaging modalities combined, but final results are awaited. The addition of MR to PET CT improved interobserver agreement in tumors of the distal third of esophagus compared to PET CT alone.

PO-1367 The value of standard chemoradiotherapy in elderly patients with adenocarcinoma of the esophagus

T. Bostel 1,2 , S. Akbaba 3,2 , D. Wollschläger 4,2 , A. Mayer 5,2 , E. Nikolaidou 5,2 , M. Murnik 6,7 , S. Kirste 6,7 , A. Rühle 6,7 , A. Grosu 6,7 , J. Debus 8,9 , C. Fottner 10,2 , M. Möhler 10,2 , P. Grimminger 11,2 , H. Schmidberger 5,2 , N.H. Nicolay 12,7,13 1 University Medical Center Mainz , Department of Radiation Oncology , Mainz , Germany; 2 German Cancer Research Center (dkfz), German Cancer Consortium (DKTK) Partner Site Mainz, Heidelberg, Germany; 3 University Medical Center Mainz , Department of Radiation Oncology , Mainz, Germany; 4 University Medical Center Mainz, Institute of Medical Biostatistics, Epidemiology and Informatics (IMBEI), Mainz, Germany; 5 University Medical Center Mainz, Department of Radiation Oncology , Mainz, Germany; 6 University of Freiburg – Medical Center, Department of Radiation Oncology , Freiburg, Germany; 7 German Cancer Research Center (dkfz), German Cancer Consortium (DKTK) Partner Site Freiburg, Heidelberg, Germany; 8 University Hospital of Heidelberg, Department of Radiation Oncology , Heidelberg, Germany; 9 German Cancer Research Center (dkfz), German Cancer Consortium (DKTK) Partner Site Heidelberg, Heidelberg, Germany; 10 University Medical Center Mainz, Department of Internal Medicine I, Mainz, Germany; 11 University Medical Center Mainz, Department of General, Visceral and Transplant Surgery, Mainz, Germany; 12 University of Freiburg – Medical Center, Department of Radiation Oncology, Freiburg, Germany; 13 University of Leipzig Medical Center, Department of Radiation Oncology, Leipzig, Germany Purpose or Objective To evaluate the tolerability and outcomes of chemoradiation in elderly patients with locally advanced adenocarcinoma of the esophagus (EACA) or gastroesophageal junction (AEG). Materials and Methods This multi-center retrospective analysis included 86 elderly patients ( ≥ 65 years) with EACA or AEG (median age 73 years; range 65 - 92 years) treated with definitive or neoadjuvant (chemo)radiotherapy between 2006 and 2020 at 3 large comprehensive cancer centers in Germany. Locoregional control (LRC), progression-free survival (PFS), distant metastasis-