Imaging and Genomic Biomarkers to Predict Response in Prostate Cancer

This is a pilot study to prospectively investigate potential predictive imaging and genomic biomarkers for patients with high-risk prostate cancer treated with standard of care EBRT + BTX + ADT. The primary imaging modalities that will be evaluated will be PSMA positron emission tomography (PET) and multi-parametric magnetic resonance imaging (MRI). Pre-treatment PET/MRI scans will also be obtained as part of standard of care prior to study enrollment. Response will be assessed on a mid-treatment PET/MRI scan obtained for research purposes after completion of EBRT but prior to brachytherapy boost. PET/CT (computerized tomography) may be used instead if PET/MRI is not technically possible. Imaging response will be compared to pathology from image-directed prostate biopsies taken at the time of the brachytherapy boost. The primary genomic marker that will be evaluated is a clinically available gene-expression array, Decipher, that will be obtained as part of standard of care prior to study enrollment.

Inclusion criteria

• Age ≥ 18
• Histologically confirmed adenocarcinoma of the prostate
• Cancer classified as high-risk or very high-risk by National Comprehensive Cancer Network (NCCN) criteria: Grade group ≥4, PSA >20, or primary tumor stage ≥T3a
• ECOG performance status 0-1
• Agreed to undergo EBRT, high dose rate (HDR) brachytherapy boost, and 6-36 months of ADT as part of standard of care therapy prior to study enrollment
• Able to undergo a HDR brachytherapy implant: Pre-radiation IPSS score ≤20 with or without medical management; prostate ≤60 cc as measured by MRI or ultrasound; no prior trans-urethral resection of prostate (TURP); and, median lobe extending into the bladder <1 cm
• No prior or concurrent malignancy unless disease-free for at least 5 years

Exclusion criteria

• Evidence of regional or distant metastatic disease on pre-treatment bone scan, pelvic MRI, and/or CT of the abdomen/pelvis
• Prior pelvic radiation therapy