ESTRO 2024 - Abstract Book

S2443

Clinical - Urology

ESTRO 2024

[2] Hamilton EJ, Gianatti E, Strauss BJ, Wentworth J, Lim-Joon D, Bolton D, et al. Increase in visceral and subcutaneous abdominal fat in men with prostate cancer treated with androgen

[3] McDonald AM, DeMora L, Yang ES, Hoyle JM, Lenzie A, Williams GR, et al. Body composition and mortality in men receiving prostate radiotherapy: A pooled analysis of NRG/RTOG 9406 and NRG/RTOG 0126. Cancer. 2023;129(5):685-96. [4] Seibold P, Webb A, Aguado-Barrera ME, Azria D, Bourgier C, Brengues M, et al. REQUITE: A prospective multicentre cohort study of patients undergoing radiotherapy for breast, lung or prostate cancer. Radiother Oncol. 2019;138:59-67.

[5] McSweeney DM, Henderson EG, van Herk M, Weaver J, Bromiley PA, Green A, et al. Transfer learning for data-efficient abdominal muscle segmentation with convolutional neural networks. Med Phys. 2022;49(5):3107-20

[6] Barnett GC, West CM, Coles CE, Pharoah PD, Talbot CJ, Elliott RM, et al. Standardized Total Average Toxicity score: a scale- and grade-independent measure of late radiotherapy toxicity to facilitate pooling of data from different studies. Int J Radiat Oncol Biol Phys. 2012;82(3):1065-74.

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Digital Poster

Detecting intraprostatic lesions in prostate cancer using Ga68 PSMA PET/CT: interobserver variations

Bennur Zeynan Devran 1 , İlknur Alsan Cetin 1 , Feyza Şen 2 , Salih Özgüven 3 , Tunç Öneş 3

1 Marmara University, Radiation Oncology, Istanbul, Turkey. 2 Pendik Training and Research Hospital, Nuclear Medicine, Istanbul, Turkey. 3 Marmara University, Nuclear Medicine, Istanbul, Turkey

Purpose/Objective:

In this study, we assessed the interobserver variability in delineating dominant intraprostatic lesions (DIL) using 68Ga-PSMA-PET/CT for optimizing radiotherapy dose escalation and explored its correlation with patient characteristics.

Material/Methods:

Retrospectively, we evaluated twenty patients diagnosed with unfavorable intermediate and high-risk prostate cancer who underwent definitive radiotherapy between November 2020 and March 2023. The delineation of DIL using 68Ga-PSMA-PET/CT was manually performed by one radiation oncologist and three nuclear medicine specialists within three months prior to radiotherapy. None of the patients had previously received hormonal therapy. Lesions were categorized based on DIL size (DILmm > 15mm, DILmm < 15mm), location (right, left), and prostate zones (peripheral zone - PZ, transitional zone - TZ). Interobserver DIL volume variability and its association with patient characteristics (PSA value, SUVmax value, total prostate volume) were assessed using the intraclass