From Clinical Trials to Clinical Practice-Patterns of Practice Survey on Prostate SABR in Australia and New Zealand.

Abstract

PurposeProstate stereotactic ablative body radiotherapy (SABR) is now a standard-of-care radiation therapy option for prostate cancer based on high-level clinical trial evidence. As part of the Australia and New Zealand (ANZ) prostate SABR guideline development process, the Royal Australian and New Zealand College of Radiologists has commissioned a pattern-of-practice survey on contemporaneous prostate SABR practice.Methods and materialsWe conducted a cross-sectional survey among ANZ genitourinary radiation oncologists (ROs), focusing on patient selection, contouring, treatment planning, and delivery of prostate SABR.ResultsA total of 53 ROs across ANZ responded to the survey (response rate: 28%). Of the 41 ROs currently offering prostate SABR, 95%, 90%, 35%, 5%, and 0% offer prostate SABR as standard-of-care options to individuals with favorable intermediate risk, unfavorable intermediate risk, favorable high risk (NINJA/ TROG18.01 trial eligible), very high risk, and node-positive prostate cancer, respectively. Most ROs (86%) routinely use fiducial markers. All ROs routinely request planning magnetic resonance imaging for contouring. Clinical target volume contouring ranged from prostate alone (26%) to prostate plus proximal 1 cm of the seminal vesicles (81%). Planning target volume margins ranged from 3 to 5 mm. An anisotropic 5 mm margin with 3 mm posteriorly was most common (56%). Nineteen (45%) ROs provide a focal boost to the intraprostatic lesion. The most common dose fractionation was 36.25 Gy to the planning target volume and 40 Gy to the clinical target volume over 5 fractions, delivered as 2 (50%) to 3 fractions (76%) per week. The majority of ROs offer prostate SABR on standard computed tomography-linear accelerator (LINAC) (88%), with several ROs also treating patients with CyberKnife (10%) and magnetic resonance-LINAC (5%). Of the ROs who use standard computed tomography-LINAC, 84% use intrafraction motion monitoring. Twelve (23%) ROs do not offer prostate SABR. The main barrier cited was a lack of expertise (42%).ConclusionsThis ANZ-wide prostate SABR pattern-of-practice survey demonstrated some variations in practice, providing contemporary insight into how prostate SABR is delivered across ANZ and highlighting barriers to wider adoption.