Detection of Clinically Significant Prostate Cancer

Background: Currently, patients suspected of having prostate cancer undergo ultrasound-guided systematic biopsies of the prostate. However, up to a quarter of clinically significant tumors, which may pose a risk to patient's well-being, may be missed on random biopsies. MRI enables detection of further tumors in this patient population, but also has limited accuracy. Study hypothesis: We hypothesize that hybrid PET-MRI, a novel scanner which incorporates MRI with molecular imaging will improve the detection rate of clinically significant tumors. Study design: In this prospective trial, we will recruit 57 men who are suspected of having prostate cancer but have had negative systematic biopsies, who have been diagnosed with low-risk disease but have clinically signs of more aggressive tumor or who have a focal tumor detected and are candidates for minimally-invasive tumor ablation (=tumor destruction with laser or ultrasound waves), in whom it is crucial to exclude other tumor sites. All patients will undergo PET/MRI after injection of a radiopharmaceutical called "18F-DCFPyL". This is a radioactive probe which has been shown in preliminary studies to be sensitive and specific for detection of prostate cancer. All lesions detected on PET/MRI will undergo biopsy under ultrasound using fused PET/MRI and ultrasound images for guidance, and compared to histopathology. The primary outcome measure in this study is the proportion of clinically significant prostate cancers that are detected with PET/MRI compared to MRI alone. Improved detection of clinically significant prostate cancer may enable a tailored, personalized therapeutic approach, decreasing morbidity and potentially improving overall patient outcome.