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.
Study Type
OBSERVATIONAL
Enrollment
30
Participants will undergo one MRI examination of approximately 45 minutes including an intramuscular injection with an antispasmodic agent to minimize bowel movement
Radboud university medical centre
Nijmegen, Netherlands
optimal combination of quantitative MRI parameters that best correlates to the presence of (lymph node) metastases in prostate cancer as seen on PSMA-PET/CT.
To find the optimal combination of quantitative parameters for discriminating between positive and negative PSMA-PET/CT, logistic regression modelling will be used. The performance of the model will be evaluated using receiver operating characteristic curve analysis.
Time frame: within 14 days of PSMA-PET/CT scan, before any therapy
the performance of individual quantitative MRI parameters discriminating localized from (oligo-)metastatic disease
To test the individual quantitative MRI parameters for a significant difference between localized and (oligo-)metastatic disease, non-parametric tests for independent groups (Mann-Whitney U test) will be used. The ability of each parameter to discriminate between positive and negative PSMA-PET/CT is assessed using receiver operating characteristic curve analysis, which allows comparison to the logistic regression model performance.
Time frame: within 14 days of PSMA-PET/CT scan, before any therapy
MR parameters that correlate to the amount of metastases as found on PSMA-PET/CT
Participants with a positive PET/CT scan result will be divided in groups according to the number of positive lymph nodes detected (if variance within participants allows). To test for significant differences between these groups for each of the quantitative parameters, the non-parametric tests for multiple independent groups (Kruskal Wallis) will be used.
Time frame: within 14 days of PSMA-PET/CT scan, before any therapy
MR parameters that correlate to local prostate PSMA-PET intensity
To test for a correlation between the quantitative parameters and the local prostate PSMA-PET intensity, a spearmans rho test for correlation between two continuous variables will be used.
Time frame: within 14 days of PSMA-PET/CT scan, before any therapy
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