Single Arm Trial of Preoperative Stereotactic Body Radiation Therapy (SBRT) for T3a or Gleason Grade Group 4 Prostate Cancer

A Single Arm Phase II Trial of Preoperative Stereotactic Body Radiation Therapy (SBRT) for T3a or Gleason Grade Group 4 Prostate Cancer

This study involves Stereotactic Body Radiation Therapy (SBRT) followed by prostatectomy (removal of the prostate). SBRT is a relatively new radiation technique in which a few doses of radiation are delivered to small, well-defined tumors. It has been used effectively in other cancers like lung and liver. The radiation will be given for only 5 days.

The purpose of this study is to compare the effects, good and/or bad, of different doses of SBRT given before prostatectomy.

• Histologically proven prostate adenocarcinoma.
• Clinical stage ≤T3a based on digital rectal exam (DRE) and ≤T3a based on MRI (within 3 months); N0-Nx; M0-Mx, or Gleason score 4 + 4. No more than 1 lymph node >1 cm.
• PSA ≤ 50 ng/ml, obtained within 3 months
• Prostate volume: ≤60 cc.
• IPSS score ≤15.
• No previous radiotherapy to the prostate or lower pelvis.
• Lymph node risk of <35% using https://www.mskcc.org/nomograms/prostate/pre\_op.
• No prior radical prostatectomy or cryotherapy of the prostate (prior transurethral resection or laser ablation are permitted).
• No implanted hardware or other material that would prohibit appropriate treatment planning or treatment delivery, in the investigator's opinion.
• No history of an invasive malignancy (other than this prostate cancer, or non-metastatic basal or squamous skin cancers) in the last 3 years.
• No androgen deprivation therapy (ADT) can be prescribed prior to or during radiation therapy.
• Participant must be able to have gold fiducial markers placed in the prostate. Note: patients can be enrolled after fiducial markers have been placed, as long as the procedure was done in accordance with the protocol (Section 4.2.2).
• Eastern Cooperative Oncology Group (ECOG) performance status ≤2
• Ability to understand and the willingness to sign a written informed consent document.
• Willing to fill out quality of life questionnaires.