Randomized Trial of Five or Two MRI-Guided Adaptive Radiotherapy Treatments for Prostate Cancer

Inclusion Criteria

• Men aged >=18 with histologically confirmed low or intermediate risk prostate cancer per NCCN guidelines.
• ECOG 0 - 1
• IPSS < 18
• Ability to receive MRI-guided radiotherapy.
• Ability to complete the Expanded Prostate Cancer Index Composite (EPIC) questionnaire.
• Patients with a prior or concurrent disease whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial. Note: Any patient with a cancer (other than keratinocyte carcinoma or carcinoma in situ or low-grade non-muscle invasive bladder cancer) who has been disease-free for less than 3 years must contact the Principal Investigator.

Exclusion Criteria

• Prior history of receiving pelvic radiotherapy.
• Patient with history of inflammatory bowel disease.
• MRI Prostate Volume > 80 cc
• MRI Stage > T3a
• Unilateral or bilateral hip replacements.
• History of bladder neck or urethral stricture.
• TURP < 8 weeks prior to radiotherapy
• Metastatic (pelvic nodal or distant) disease on CT, Bone, Fluciclovine, and/or PSMA PET scan