The primary aim of this study is to assess the potential of quantitative MRI measurements to predict localized prostate cancer T-stage and disease spread to nodes (N-stage) by correlating quantitative MRI measurements of the local prostate to the presence of metastases as seen on PSMA-PET/CT.

Patients diagnosed with prostate cancer will likely not die from the primary tumor, but from (extended) metastatic disease. One of the first steps towards extended metastatic disease is the presence of lymph node metastases, which is an important factor in determining therapy and prognosis. Although historically all patients with lymph node metastases are considered incurable, research has shown that patients with only a limited number of small (<8 mm) nodal metastases have a better prognosis as compared to patients with more extensive involvement. In patients with only a limited number of small nodal metastases (oligo-metastatic), therapy with curative intent might be pursued, e.g. by surgical resection or loco-regional radiotherapy. With continuously improving opportunities to very selectively treat small numbers of metastatic sites it is of utmost importance to accurately diagnose the first signs of oligo-metastatic disease and to define its extent.

It is hypothesized that magnetic resonance imaging (MRI) can obtain more information from the local prostate than what is now used in the clinic to stage localized prostate cancer and oligo-metastatic disease. In recent years positron emission tomography (PET) in combination with computerized tomography (CT) and Prostate Specific Membrane Antigen (PSMA) tracers (PSMA-PET/CT) has emerged as an imaging modality to visualize (early) metastatic disease, but its accuracy in detecting oligo-metastatic spread is unknown, as small nodal metastases can be missed. In this study, the correlation is assessed between functional, quantitative and metabolic local tumor characteristics with PSMA-PET/CT-proven nodal involvement, to be able to predict metastatic potential from quantitative MRI parameters of the localized tumor. If the study shows potential for predicting presence of metastatic disease, future patients will benefit from improved nodal staging, potentially leading to more accurate and personalized treatment of the correct disease stage.

Inclusion Criteria:

• Histologically proven primary cancer of the prostate, based on prostate biopsy-core analysis.
• Patient is scheduled and fit for PSMA-PET/CT
• Age≥50 years. Ability to give voluntary written informed consent to participate in this study.

Exclusion Criteria:

• Contraindication for MRI-scanning, i.e. claustrophobia, intracranial metal clips, metallic bodies in the eye, implanted electric and electronic devices not eligible for MRI (pacemakers, insulin pumps, cochlear implants, neurostimulators).
• Prior prostate cancer treatment.
• Prior pelvic surgery, associated with pelvic lymphadenopathy
• Presence of any medical condition that in the opinion of the investigator/treating physician will affect patients' clinical status by participating in this trial.
• Inability to lie still for 45 minutes or comply with imaging.
• The patient is already enrolled in one or more concurrent studies, which could confound the results of this study, according to the investigators.

Patients, diagnosed with prostate cancer by prostate biopsy and having a high risk of nodal metastases, will be recruited at the Radboudumc in Nijmegen. This research population will be a suitable reflection of the potential patient group who will eventually benefit from this new diagnostic mpMRI approach, in case the results match the hypothesis. Characteristics of this group will comprise all men with an expected age in the range of 50-75 years.

Patients will be informed about the ongoing study by their treating physician. Patients will receive the patient information folder and will be contacted by one of the researchers. Upon approval, informed consent paperwork will be handed.