Evaluation of Tumor Control Based on Serial Multiparametric MRI and Post-Treatment Biopsies For Patients Treated With Dose Intensification to the Dominant Intra-Prostatic Lesion (DIL) Using Ultra-Hypofractionated, MR-Guided Radiotherapy

Prior treatment

• Prior or concurrent androgen deprivation therapy for prostate cancer
• Metallic implant or device in the pelvis that might distort the local magnetic field and compromise quality of mp-MRI
• Contra-indications to receiving gadolinium contrast
• Prior history of transurethral resection of the prostate
• Prior history of urethral stricture
• Prior history of pelvic irradiation

Other illness

• MRI findings: \>2 disease foci identifiable
• Evidence of metastatic disease on bone scan or MRI/CT
• MRI ineligibility due to: the presence of a cardiac pacemaker, defibrillator, or other implanted metallic or electronic device which is considered MR unsafe; severe claustrophobia; inability to lie flat for the duration of the study; etc.
• Pelvic or Prostate MRI or CT (MRI preferred) evidence of radiographic T3, T4, or N1 disease
• History of inflammatory bowel disease

Lab values

• Abnormal complete blood count, including any of the following:
  • Platelet count less than 75,000/ml
  • Hb level less than 10 gm/dl
  • White blood cell (WBC) less than 3.5/ml
  • Abnormal renal function tests (creatinine \> 1.5)

Other

• Gleason score \>7
• PSA \>20 ng/mL
• MRI findings: suspicious for/probable ECE
• Lateral pelvic separation greater than 50 cm and/or anterior-posterior separation greater than 35 cm which are incompatible with MR for Calculating ATtenuation (MRCAT) reconstruction
• KPS \< 80
• Unable to give informed consent
• Unable to complete quality of life questionnaires

• Intermediate-risk prostate cancer patients will be eligible for this study. Risk groups will be assigned as per National Comprehensive Cancer Network (NCCN) guidelines. Intermediate-risk patients will be defined as:
  • PSA 10-20 ng/ml or
  • Gleason score = 7 or
  • Clinical stage T2b/T2c (T2b: the tumor has spread to more than one-half of one side of the prostate, but not to both sides. T2c: the cancer has invaded both sides of the prostate)
• Age \> 18
• Karnofsky Performance Status (KPS) \> 80
• Prostate size \< 90 cc
• Presence of a T2-visible prostatic lesion with maximum dimension of ≥ 0.5 cm and no more than two additional disease foci with a documented Prostate Imaging Reporting and Data System (PIRADS) 4-5 lesion
• MRI findings: Lesion may contact the capsular edge, possible extracapsular extension (ECE) permitted
• International Prostate Symptom Score \< 18
• Satisfy all MRI screening criteria and be willing to fill out the standard MRI screening form