Rationale for Modernising Imaging in Advanced Prostate Cancer

Abstract

Context: To effectively manage patients with advanced prostate cancer (APC), it is essential to have accurate, reproducible, and validated methods for detecting and quantifying the burden of bone and soft tissue metastases and for assessing their response to therapy. Current standard of care imaging with bone and computed tomography (CT) scans have significant limitations for the assessment of bone metastases in particular.

Objective: We aimed to undertake a critical comparative review of imaging methods used for diagnosis and disease monitoring of metastatic APC from the perspective of their availability and ability to assess disease presence, extent, and response of bone and soft tissue disease.

Evidence acquisition: An expert panel of radiologists, nuclear medicine physicians, and medical physicists with the greatest experience of imaging in advanced prostate cancer prepared a review of the practicalities, performance, merits, and limitations of currently available imaging methods.

Evidence synthesis: Meta-analyses showed that positron emission tomography (PET)/CT with different radiotracers and whole-body magnetic resonance imaging (WB-MRI) are more accurate for bone lesion detection than CT and bone scans (BSs). At a patient level, the pooled sensitivities for bone disease by using choline (CH)-PET/CT, WB-MRI, and BS were 91% (95% confidence interval [CI], 83-96%), 97% (95% CI, 91-99%), and 79% (95% CI, 73-83%), respectively. The pooled specificities for bone metastases detection using CH-PET/CT, WB-MRI, and BS were 99% (95% CI, 93-100%), 95% (95% CI, 90-97%), and 82% (95% CI, 78-85%), respectively. The ability of PET/CT and WB-MRI to assess therapeutic benefits is promising but has not been comprehensively evaluated. There is variability in the cost, availability, and quality of PET/CT and WB-MRI.

Conclusions: Standardisation of acquisition, interpretation, and reporting of WB-MRI and PET/CT scans is required to assess the performance of these techniques in clinical trials of treatment approaches in APC.

Patient summary: PET/CT and whole-body MRI scans have the potential to improve detection and to assess response to treatment of all states of advanced prostate cancer. Consensus recommendations on quality standards, interpretation, and reporting are needed but will require validation in clinical trials of established and new treatment approaches.

Keywords: Advanced prostate cancer; Bone scans; Diffusion MRI; Metastasis detection; Metastatic castrate-resistant prostate cancer; PET/CT scans; Response assessment; Whole-body MRI.