Analysis of the Performance of PSMA Emission Tomography in Patients With Prostate Cancer Treated With HIFU

Overview

There would appear to be a strong interest in functional nuclear imaging for assessing the response to focal PaC treatment. Investigator team hypothesise that the diagnostic performance of PSMA PET is noninferior to that of MRI in detecting clinically significant recurrent PaC after treatment with HIFU. The main objective was to evaluate the diagnostic performance of PSMA PET compared with MRI with reference to the gold standard of prostate biopsy one year after HIFU.

The management of localised prostate cancer (PaC) in men with favourable risk factors is contentious, often involving whole prostate treatment due to its multifocal nature in 40% of cases. Active surveillance (AS) is increasingly used to mitigate overtreatment risks in well-selected patients, supported by long-term data from large cohorts. Focal therapy is emerging as an alternative, aiming for effective cancer control while minimizing morbidity, with radical treatment available for relapse. High-intensity focused ultrasound (HIFU) shows promise for focal therapy, supported by the HIFI-1 study and the HAS report (November 2023), indicating its non-inferiority to radical prostatectomy in controlling intermediate-risk disease with less morbidity.PSMA PET imaging aids in diagnosing and assessing prostate cancer risk at diagnosis and after treatment, guiding management decisions. However, ultrasound artefacts can hinder MRI interpretation post-HIFU treatment. PSMA PET, particularly using PRIMARY score and PROMISE V2 criteria, helps in assessing disease extent, akin to miTNM classification based on cancer location and spread on molecular imaging. Overall, integrating these technologies and criteria improves the precision of prostate cancer diagnosis, risk estimation, and treatment planning The aim of this study is to evaluate the effectiveness of positron emission tomography (PSMA PET) compared with MRI in detecting clinically significant recurrence of prostate cancer (PaC) after treatment with HIFU. The aim is to measure the sensitivity and specificity of these two imaging modalities one year after treatment, with a view to improving the post-treatment follow-up strategy for PaC Patients with low intermediate risk prostate cancer with specific criteria (HAS 2023) will be included in the study. Pre-operative nuclear imaging will be performed in addition to routine diagnostic tests. Routine follow-up at 6 months will include a digital rectal examination (DRE) and PSA and Phi index measurements. At 1 year, in addition to routine follow-up (DRE, PSA, Phi index, MRI and prostate biopsy), patients will undergo a PSMA PET scan.