Image-Guided Radiotherapy for Pelvic Cancers: A Review of Current Evidence and Clinical Utilisation

Abstract

The meticulous selection and utilisation of image-guided radiotherapy treatment (IGRT) are essential for optimal radiotherapy treatment delivery when using highly conformal treatment techniques in pelvic radiotherapy. Pelvic IGRT has several general IGRT issues to consider (such as choice of match strategy, prioritisation between multiple treatment targets, and margin estimates) as well as issues specific to pelvic radiotherapy, in particular large interfraction organ variation. A range of interventions, including adaptive treatment strategies, have been developed to address these challenges. This review covers general considerations for clinical implementation of pelvic IGRT in routine practice and provides an overview of current knowledge regarding pelvic interfraction organ motion. Published IGRT evidence for each of the major tumour sites (gynaecological, prostate, bladder, rectal and anal cancer) is summarised, as are state-of-the-art adaptive approaches. General recommendations for implementation of an institutional pelvic IGRT strategy include• Ensuring consistency between treatment intent and IGRT approach utilised.• Ensuring minimum national and international IGRT guidance is followed whilst considering the benefit of daily volumetric IGRT. • Ensuring the appropriate Allied Health Professionals (namely Therapy Radiographers/RTTs) lead on undertaking IGRT. • Ensuring the IGRT workflow procedure is clear and includes an escalation process for difficult set-ups. • Ensuring a robust IGRT service is in place before implementing advanced adaptive approaches.

Image-guided Adaptive Radiotherapy for Bladder Cancer

“…It requires iterative training, quality assurance and competency assessment. How this could be successfully achieved has been reviewed elsewhere [48,50,85,122,126,127].…”

A practical approach to bladder preservation with hypofractionated radiotherapy for localised muscle-invasive bladder cancer

“…The bladder is subject to significant day to day variation in size and shape that can result in target misses. Using Cone beam CTs (CBCT) to provide three-dimensional soft-tissue images (‘image guided radiotherapy’) obtained immediately prior to treatment allows adjustments in machine set-up or patient position to ensure optimal coverage and avoid [24] , [25] .…”

Adaptive Radiotherapy in the Management of Cervical Cancer: Review of Strategies and Clinical Implementation

“…With improving online image quality using cone beam computed tomography (CBCT), there has been a move towards image-guided radiotherapy with soft-tissue matching as standard [27]. Alongside this, ART strategies have been utilised, including scheduled replanning or a plan of the day (PotD) approach [27].…”

“…With improving online image quality using cone beam computed tomography (CBCT), there has been a move towards image-guided radiotherapy with soft-tissue matching as standard [27]. Alongside this, ART strategies have been utilised, including scheduled replanning or a plan of the day (PotD) approach [27]. More recent technological developments have introduced the clinical possibility of online ART (oART) with daily replanning using magnetic resonance [28] or CBCT guidance [29].…”