A proof of concept study evaluating the role of emerging ultrasound technologies in the active surveillance of localised prostate cancer

Parker, Pamela Claire

Abstract

Background
Although one in eight men will develop some form of prostate cancer (PCa) within their lifetime, not all PCa is of high-risk of progression. In such cases active surveillance (AS) provides an alternative to radical treatment (Hamdy et al., 2023; Wilt et al., 2020). However, inconsistencies in AS regimes exist (Merriel et al, 2019), and capacity for surveillance magnetic resonance imaging (MRI), required to identify progression, is limited. Novel high frequency ultrasound (microUS) potentially offers an alternative imaging solution in AS.
Aims
This proof-of-concept trial aimed to determine if there was a role for emerging ultrasound technologies in the monitoring of PCa in men on AS, and to better understand how this technology could be implemented and embedded into clinical practice.
Method
This prospective single-centre trial was undertaken in two discreet studies. Study 1 comprised of a cross-sectional study of 100 patients presenting with suspected PCa who underwent MRI and ultrasound (US) guided biopsy (phase 1), and a longitudinal study of 10 patients with low-risk disease managed on an AS pathway (phase 2). All patients underwent transrectal US imaging using both standard and microUS transducers. Images were retrospectively analysed by two reviewers and risk stratified. Agreement rates between reviewers, MRI, and histological outcomes post biopsy were calculated.
Study 2 was a longitudinal study of practitioner experience of the new technology, informed by normalisation process theory (NPT). Data was collected at three points during the study and analysed narratively.
Results
Study 1, phase 1: Agreement between individual reviewers and histology was poor and ranged from 26.7% to 56.7% for standard ultrasound and 25.9% to 56.7% for microUS. Sensitivity of standard ultrasound was calculated to be 48% with a specificity of 75%. A kappa value of 0.21 was determined by assessing the inter-rater reliability (IRR). Retrospective review of microUS had a sensitivity and specificity of 77% and 40% respectively with a higher, but only fair, IRR kappa score of 0.31. Performance of microUS was improved when scored in real-time by two practitioners, with sensitivity and specificity of 73.3% and 53.8% respectively identified, and an improved IRR of 0.38 was determined when calculated as a weighted kappa.
Study 1, phase 2: Twenty follow-up scans were performed across 10 patients. Change in appearances at microUS was noted by one reviewer in one follow-up scan, but this change remained within the low-risk stratification. Little consistency between scores of the monitoring scans and the baseline assessment was identified, and a lack of clinical confidence in this test curtailed this study phase.
Study 2: Data from the initial survey identified positive engagement and support for microUS. However, findings from the subsequent surveys indicated that microUS was difficult to use and interpret. Evidence from this study suggests that microUS is not currently normalised into routine practice.
Conclusion
A role for ultrasound within the prostate cancer AS pathway has not been identified during this trial. However, study 1, phase 1 findings suggest that microUS could be used for screening in patients in whom MRI is contraindicated. Further research in this area is required.

Citation

Parker, P. C. A proof of concept study evaluating the role of emerging ultrasound technologies in the active surveillance of localised prostate cancer. (Thesis). University of Hull. https://hull-repository.worktribe.com/output/4866373

• Thesis Type: Thesis
• Deposit Date: Oct 15, 2024
• Publicly Available Date: Oct 29, 2024
• Keywords: Health studies
• Public URL: https://hull-repository.worktribe.com/output/4866373
• Additional Information: Faculty of Health Sciences; University of Hull
• Award Date: Jun 19, 2024