ESTRO 2024 - Abstract Book

S2416

Clinical - Urology

ESTRO 2024

longer follow-up are required to determine if any pre-treatment factors may correlate with improved outcomes after SABR.

Keywords: Prostate, SABR, Oligometastases

References:

1 Ost P, Reynders D, Decaestecker K, Fonteyne V, Lumen N, De Bruycker A, et al. Surveillance or Metastasis-Directed Therapy for Oligometastatic Prostate Cancer Recurrence: A Prospective, Randomized, Multicenter Phase II Trial. Journal of Clinical Oncology. 2018 Feb 10;36(5):446 – 53.

2 . Phillips R, Shi WY, Deek M, Radwan N, Lim SJ, Antonarakis ES, et al. Outcomes of Observation vs Stereotactic Ablative Radiation for Oligometastatic Prostate Cancer. JAMA Oncology. 2020 May 1;6(5):650

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Digital Poster

Comparison of ESTRO-ACROP and PERYTON guideline for CTV delineation for salvage radiotherapy

Daniel Rusche 1 , Marco M E Vogel 1 , Lucas Etzel 1 , Stephanie E Combs 1,2,3 , Jan C Peeken 1,2,3

1 Klinikum rechts der Isar, Technical University of Munich (TUM), Department of Radiation Oncology, Munich, Germany. 2 Deutsches Konsortium für Translationale Krebsforschung, Partner Site Munich, Munich, Germany. 3 Institute of Radiation Medicine, Helmholtz Zentrum, Department of Radiation Sciences, Munich, Germany

Purpose/Objective:

Recently, two new guidelines were published for the delineation of the clinical target volume (CTV) for post prostatectomy salvage radiation therapy (sRT), namely the ESTRO-ACROP (EA) [1] and PERYTON (PY) guideline [2]. There exists a considerable difference in the CTV especially for the definition of the bladder overlap and anterior margin. Our aim was to measure the differences between the two CTV definitions as these numbers might already portrait a relevant distinction in later dose and toxicity differences.

Material/Methods:

We selected 20 patients who received sRT from the Department of Radiation Oncology at the Klinikum rechts der Isar. Patients with tumors pT3b or higher, rectal balloon, contrast enhancement, endoprosthesis, or scans in abdominal position were excluded. The CTV was delineated for each scan in accordance with ESTRO-ACROP and PERYTON guideline respectively by a fist-year-resident and reviewed by an expert radiation oncologist (J. P.). One major difference between the guidelines is the coverage of the bladder wall. After anonymization and export of the CTV and organs at risk segmentations, the label maps were converted to Neuroimaging Informatics Technology Initiative (NIFTI) files with slicer (version 5.4.0) and statistically analyzed using Python 3.9 and its libraries. The