PET/MRI for Men Being Considered for Radiotherapy for Suspected Prostate Cancer Recurrence Post-Prostatectomy

The study will be a non-randomized, prospective study of men with suspected local recurrence of prostate cancer post-prostatectomy with negative conventional re-staging studies (bone scan and CT of the abdomen and pelvis; MRI of the pelvis as part of re-staging is allowed where it is the institutional standard of care). The clinician will develop an initial treatment plan based on conventional re-staging information.

Patients enrolled onto trial will undergo hybrid PET/MR imaging using 18F-FCH (sites without access to a hybrid PET/MR scanner will conduct a 18F-FCH PET/CT in addition to a full body MRI). A consensus staging report based on local and centralized review of the 18F-FCH PET imaging will be provided to the attending clinician, who will document a second treatment plan based on this additional information. The treatment plan to be implemented (initial or second) will be left to clinician discretion, but will be documented.

Inclusion criteria

• Male, aged 18 years or older.
• Confirmation of prostate cancer on prostatectomy pathology report.
• No lymph node involvement (N0 or Nx) reported on prostatectomy pathology report.
• Documented PSA rise measured on 3 occasions.
• PSA ≥ 0.2 ng/ml at enrolment.
• At least one adverse feature: Current PSA > or equal to 1.0, Initial Gleason Grade > or equal to 8, Positive surgical margin, pT3b (seminal vesicle involvement), or PSA doubling time < 10 months.
• Bone scan and CT scan within 12 weeks of enrolment negative or equivocal for metastatic disease.
• Suitable candidate for radiotherapy and not yet had any salvage treatment post-prostatectomy.

Exclusion criteria

• Prostate cancer with significant sarcomatoid or spindle cell or neuroendocrine small cell components.
• Proven metastatic disease.
• Patients who refuse salvage prostate bed radiotherapy.
• Patients who refuse to join the trial or are unable to consent.
• Patients not being considered for further therapy.
• Patients who cannot lie still for at least 30 minutes or comply with imaging.
• Unequivocal evidence of disease outside the prostate bed on conventional imaging
• Allergy to MRI contrast agent (exclusion for MRI component only) or PET tracer to be used as part of the imaging
• Sickle cell disease or other anemias
• Insufficient renal function (eGFR < 30 mL/min/1.73 m2)
• Residual bladder volume > 150 cc (determined by post-void ultrasound)
• Hip prosthesis, vascular grafting or other conditions affecting imaging or delivery of therapeutic radiation
• Contraindication to MRI, including but not restricted to: pacemaker or other electronic implants, known metal in the orbit, MR incompatible surgical or cerebral aneurysm clips, Shrapnel, tattoos, non-removable body piercings (relative contraindications)
• Hormone Androgen deprivation therapy of any type within 6 months prior to enrollment