ESTRO 2024 - Abstract Book

S2572

Clinical - Urology

ESTRO 2024

Conclusion:

Daily-adaptive MR-guided SBRT to the prostate using Comprehensive Motion Management has been successfully implemented into clinical routine. The whole process is safe and completely automated even in the case on in treatment corrections and baseline shift replanning. CMM could allow now a safe reduction of the treatment margins with a guided workflow to manage real tracking and gating.

Keywords: MR-Linac, adaptive, gating

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Digital Poster

Is there an association between inter-fraction motion during prostate SABR and quality of life?

Orla A Houlihan 1,2 , Niamh Clarke 3 , Christina Agnew 3 , Owen McLaughlin 1,3 , Ciara Lyons 1,2 , Aidan Cole 1,2 , Joe O'Sullivan 1,2 , Kevin M Prise 1 , Alan R Hounsell 3 , Darren M Mitchell 2 , Conor McGarry 3 , Suneil Jain 1,2 1 Queen’s University Belfast, Patrick G. Johnston Centre for Cancer Research, Belfast, United Kingdom. 2 Northern Ireland Cancer Centre, Belfast City Hospital, Clinical Oncology, Belfast, United Kingdom. 3 Northern Ireland Cancer Centre, Belfast City Hospital, Radiotherapy Medical Physics, Belfast, United Kingdom

Purpose/Objective:

Patient-reported outcomes are important as they give a direct indication of the impact of a disease and its treatment on patients’ quality of life (QOL) [1]. With advances in radiotherapy and improved tumour outcomes in recent years, minimising treatment-related toxicities after treatment is increasingly important [2, 3]. During prostate SABR, the potential exists for movement of the rectum and bladder, as these are mobile organs at risk (OARs). This study explored whether pre-fraction CBCTs provided a better indication of patient-reported QOL scores, as measured by the Expanded Prostate Cancer Index Composite (EPIC), than the planning CT for patients in a randomised trial of SABR ± elective nodal irradiation in high-risk prostate cancer (SPORT trial).

Material/Methods:

In the SPORT trial, 30 men were randomised 1:1 to SABR to prostate-only (P-SABR) or to prostate plus pelvic lymph nodes (PPN-SABR). P-SABR patients received 36.25Gy/5 fractions/29 days. PPN-SABR patients also received 25Gy/5 fractions to pelvic nodes with the final cohort receiving a boost to the dominant intraprostatic lesion of 45-50Gy. A CBCT was performed prior to each weekly fraction. Retrospectively the bladder and rectum were contoured on each pre-fraction CBCT. OAR dose/volume constraints (DVCs) were averaged across all five pre-fraction CBCTs and compared to their respective DVCs as determined by the planning CT. Acute patient-reported EPIC QOL scores were measured from commencement of treatment to 90 days post-completion of SABR. Late EPIC QOL scores were measured from 90 days to 36 months post-completion of SABR. DVCs for rectum were V18.1Gy <50%, V29Gy <20%