Prostate cancer (PCa) is the second most common diagnosed malignancy in males worldwide, with over 1.2 million new patients diagnosed every year. Since the introduction of prostate-specific antigen (PSA) the primary diagnosis consisted of histologic confirmation by transrectal ultrasound (TRUS) systematic biopsies. However, in recent years this has changed into performing multi-parametric MR imaging (mpMRI) prior to prostate biopsy.
MpMRI has proven to be a valuable tool to avoid unnecessary prostate biopsies and prevent over-treatment of low-grade PCa, while maintaining equal or higher detection rates of high-grade PCa. Prostate MRI is evaluated using the Prostate Imaging-Reporting and Data System (PIRADS). Lesions are given a category score, from 1 (high-grade PCa is unlikely to be present) to 5 (presence of high-grade PCa is highly likely). A PIRADS 3 is an equivocal scan. Nonetheless, mpMRI has room for improvement as its specificity for high-grade tumors is only 73% and local staging is limited with mpMRI. Also, the mpMRI is frequently unclear as 4-39% of detected lesions are classified as PIRADS 3.
Prostate-specific membrane antigen receptor (PSMA) is highly overexpressed by 95% of the prostate cancer cells and seem to positively correlate to aggressiveness of the tumor. PSMA-positron emission tomography (PET) uses this feature by visualizing PSMA expressing prostate tumors. Currently, the PSMA-PET is generally used to detect recurrences or metastases. However, there is an increasing interest for PSMA-PET scans in patients with a primary diagnosis of PCa for staging purposes. Yet, there is no published data on the role of PSMA-PET on PCa prior to biopsy in comparison to the detection rate of mpMRI and histopathology.
This study aims to investigate the added value of a 18F-PSMA-PET to mpMRI in the detection of local prostate cancer lesions.
75 patients with the suspicion on prostate cancer (e.g. elevated PSA and/or abnormal digital rectal exam) will receive a 18F-PSMA-1007 PET following mpMRI. 25 patients with PIRADS 1-2 (probably benign disease), 25 patients with PIRADS 3 (equivocal disease) and 25 patients with PIRADS 4-5 (highly suspicious for malignancy) will be included in this study.
If either the mpMRI or 18F-PSMA-1007 PET shows a potential malignant lesion, a (target) biopsy will be performed.
