ESTRO 2024 - Abstract Book

S2621

Clinical - Urology

ESTRO 2024

A total of 60 events was assessed in CRFS analysis, with a median time of 18.7 (95% CI, 15.2-NA) years. Multivariate Cox analysis identified N1 at primary diagnosis (HR 2.04, 95% CI 1.08-3.86, p = 0.03), ISUP4-5 (HR 1.95, 95% CI 1.12 3.38, p = 0.02), and ADT usage of ≥ 2 years (HR 1.76, 95% CI 1.03 -3.02, p = 0.04) as independent CRFS predictors. PMFS analysis included 72 events with a median time of 17.7 (95% CI, 12.9-NA) years. Key PMFS predictors included ISUP4-5 (HR 2.34, 95% CI 1.43-3.84, p < 0.01), M1b at first recurrence (HR 1.83, 95% CI 1.14-2.94, p = 0.01), 4-5 lesions at first recurrence (HR 5.46, 95% CI 1.57-18.97, p < 0.01), MDT not always to all lesions at imaging (HR 2.70, 95% CI 1.58-4.61, p < 0.01).

Conclusion:

This study highlights the comprehensive management of omHSPCa, from diagnosis to treatment outcomes. The findings underscore the significance of personalized treatment approaches, the potential benefits of integrating ADT, and the pivotal role of MDT. Additionally, the endpoints analyzed have economic implications. Delaying castration resistance could lead to significant cost savings while enhancing the patient's quality of life.

Keywords: imaging, oligometastatic, mdt

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Impact of Intrafractional Bladder Filling on Prostate Motion using MR-guided Adaptive Radiation.

Victoria S Brennan 1 , Nicolas Cote 2 , Chengcheng Gui 1 , Sarah Burleson 2 , Neelam Tyagi 2 , James Mechalakos 2 , Zhigang Zhang 3 , Nicolas Toumbacaris 3 , Michael J Zelefsky 4 1 Memorial Sloan Kettering Cancer Center, Radiation Oncology, New York, USA. 2 Memorial Sloan Kettering Cancer Center, Medical Physics, New York, USA. 3 Memorial Sloan Kettering Cancer Center, Epidemiology-Biostatistics, New York, USA. 4 Perlmutter Cancer Center, NYU Langone Health, Radiation Oncology, New York, USA

Purpose/Objective:

Prostate cancer is increasingly being treated using ultrahypofractionated radiation regimens. Magnetic resonance image (MRI)-guided radiation on the MR linear accelerator (MRL) may have advantages over the conventional C-arm linac due to the ability to adapt the treatment plan daily in response to interfraction anatomic changes. Patients typically comply with a bladder filling protocol for prostate radiation, maintaining a consistently full bladder to ensure reproducibility of prostate location as well as elevating bowel out of the radiation field. Treating with daily adaptive planning on the MRL increases the overall the overall treatment time, which may increase patient discomfort associated with prolonged bladder filling. Initiating each treatment fraction with an empty bladder on the MRL and utilizing secondary adaptive planning to account for interval prostate motion may improve patient comfort without compromising target coverage. We aim to evaluate the degree of bladder filling observed in