SALT studie – Stadiëring met [18F]PSMA PET voorafgaand aan lymfeklierdissectie bij patiënten met een prostaattumor

Background: Prostate cancer is the most common cancer in men of older age in Western countries. Treatment of prostate cancer varies greatly depending on the stage of the disease, making accurate diagnostic procedures essential. Diagnostic accuracy of conventional imaging modalities (e.g. bone scintigraphy, CT, MRI) for the detection of (lymph node) metastases however, proved to be limited. To improve detection of metastases, radiotracers have been developed for PET/CT imaging: i.e. radiolabelled Prostate Specific Membrane Antigen (PSMA) ligands. Initial studies with Gallium-68 labelled PSMA ([68Ga]PSMA) showed promising results. The second generation of Fluorine-18 labelled PSMA, 2-(3-(1-carboxy-5-[(6-[18F]fluoro-pyridine-3-carbonyl)-amino]-pentyl)-ureido)- pentanedioic acid ([18F]DCFPyL) has the potential to offer even better diagnostics. Compared to [68Ga]PSMA, [18F]DCFPyL has a higher image resolution and a longer half-life. The present study therefore investigates the role of [18F]PSMA PET/CT for primary staging of intermediate- to high risk prostate cancer.

Objective: Evaluation of the diagnostic accuracy of [18F]PSMA PET/CT for the detection of (regional) lymph-node metastases (LNMs) and distant (bone) metastases in intermediate-and high-risk prostate cancer patients; comparison of performance to [68Ga]PSMA PET/CT.



Study design: Multicenter prospective observational study.

Study population: Newly diagnosed patients with intermediate- to high-risk prostate cancer, planned for an extended pelvic lymph node dissection (ePLND), with preceding [18F]PSMA PET/CT scan.

Study procedure: [18F]PSMA PET/CT results will be correlated to histologic findings. Changes in management prompted by the imaging results will be recorded.



Main study parameters/endpoints: Patient- and lesion-based sensitivity, specificity, NPV and PPV of [18F]PSMA PET/CT for the detection (regional) LNMs and distant (bone) metastases;

In primary prostate cancer patients, the exisstence of lymph node metastases is associated with developmment of distant metastases and negatively associated with cancer-specific survival.

The performance of an extended lymph node dissection (ePLND) is the current clinical standard to provide accurate lymph node staging (N-stage). An ePLND is an invasive procedure, however, and associated with complications such as lymphocèle, deep venous trombosis, and longer hospital stay.



A novel imaging technique have been recently developed: prostate-specific membrane antigen (PSMA) PET/CT, wich has demonstrated very promising results. In this study an [18 Flourine] labelled PSMA radiotracers wil be studied, [18F]DCFPyL. Diagnostic accuracy of [18F]DCFPyL will be assessed in primary prostate cancer patients and compared to histopathology results following ePLND (reference standard). Furthermore, the diagnostic results will be compared to the results of the PEPPER trial (UMC Utrecht), studying the [68Ga]PSMA in the same patiens.

Preoperative [18F]DCFPyL PET/CT