Optimising dominant intraprostatic lesion outlining for prostate radiotherapy

Evans, Elin 2023. Optimising dominant intraprostatic lesion outlining for prostate radiotherapy. MD Thesis, Cardiff University. Item availability restricted.

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Abstract

The dominant intraprostatic lesion (DIL) is the most common source of local recurrence following radiotherapy for localised prostate cancer. Recent trial findings suggest dose escalation to the DIL results in a low chance of prostate cancer recurrence at five years and confers minimal excess toxicity compared to standard prostate radiotherapy dose and fractionation schedules. Defining the DIL to outline for radiotherapy planning requires mpMRI interpretation skills and the ability to cognitively transfer the mpMRI defined DIL onto the CT planning scan. Outlining variation amongst radiotherapy outliners across all tumour sites is a well-recognised limitation in the radiotherapy planning pathway. Strategies to minimise inter-observer outlining variation include implementation of tumour sitespecific outlining guidelines and educational outlining workshops. This thesis explores the incidence of outlining variation of the DIL amongst UK prostate oncologists using data from the pre-accrual benchmark case submissions of the PIVOTALboost trial; a phase III randomised control trial of prostate and pelvis versus prostate alone radiotherapy, with or without DIL dose-escalation. Having established a high rate of case resubmission, predominantly due to unacceptable DIL outlining variation, the thesis then explores the role of conformity indices as a semiautomated tool in the assessment of unacceptable versus acceptable outlining variation in the PIVOTALboost pre-accrual benchmark case submissions. Thereafter, this thesis evaluates the impact of an outlining workshop on DIL outlining performance of UK prostate oncologists. Finally, this thesis investigates which step within the DIL outlining process is the cause of outlining variation; i.e. mpMRI interpretation or cognitive transfer, to inform future work aimed at minimising DIL outlining variation.

Item Type:	Thesis (MD)
Date Type:	Completion
Status:	Unpublished
Schools:	Medicine
Date of First Compliant Deposit:	13 October 2023
Last Modified:	13 Oct 2023 08:23
URI:	https://orca.cardiff.ac.uk/id/eprint/163160

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