ESTRO 2024 - Abstract Book

S2345

Clinical - Urology

ESTRO 2024

Prostate stereotactic radiotherapy delivered as a VHDR boost is well tolerated overall, however delayed genitourinary toxicity is experienced by a subset of patients. Contouring of the urethra is currently not standard but these findings support contouring the urethra routinely. A strict dose constraint on the bladder D10cc, bladder D15cc and bladder V8 should be used in future studies to help prevent genitourinary toxicity. Dose constraints of bladder D10cc < 17Gy, bladder D15cc < 15Gy and bladder V8 < 45% could be used.

Keywords: Stereotactic, prostate, toxicity

References:

1) Bhattasali O, Chen LN, Woo J, Park JW, Kim JS, Moures R, Yung T, Lei S, Collins BT, Kowalczyk K, Suy S. Patient reported outcomes following stereotactic body radiation therapy for clinically localized prostate cancer. Radiation oncology. 2014 Dec;9(1):1-0. 2) Richardson M, Sidhom M, Gallagher S, Grand M, Pryor D, Bucci J, Wilton L, Arumugam S, Keats S, Martin JM. PROstate Multicentre External beam radioTHErapy Using a Stereotactic boost: the PROMETHEUS study protocol. BMC Cancer. 2018 May 24;18(1):588.

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Improving the accuracy of urethral delineation for prostate SBRT planning

Raguprakash Ratnakumaran 1,2 , Samuel J Withey 3 , Rosalyne Westley 1,2 , Shaisha Hafeez 1,2 , Julia Murray 1,2 , Chris Parker 1,2 , Jun-Hao Lim 4 , Binnaz Yasar 1,2 , Yae-eun Suh 1 , Nicholas van As 1,2 , Alison C Tree 1,2 1 The Royal Marsden NHS Foundation Trust, Urology Unit, London, United Kingdom. 2 The Institute of Cancer Research, Radiotherapy and Imaging, London, United Kingdom. 3 The Royal Marsden NHS Foundation Trust, Radiology, London, United Kingdom. 4 Nottingham University Hospitals NHS Trust, Clinical Oncology, Nottingham, United Kingdom

Purpose/Objective:

The urethra is a crucial genitourinary structure, especially in prostate stereotactic body radiotherapy (SBRT), as excessive urethral dose can lead to increased risk of urinary toxicity. However, it is not possible to visualise the urethra on CT imaging, and therefore MRI planning scans are often needed. Unfortunately, delineating the urethra on MRI remains challenging, and there are currently no validated contouring approaches. We evaluated the effectiveness of a radiologist-led delineation teaching session and a newly-devised urethra contouring guideline in improving prostatic urethra delineation.

Material/Methods: