Two Fraction Prostate SBRT With DIL SIB

Inclusion Criteria: Patient age greater than or equal 18 Localized adenocarcinoma of the prostate Biopsy-proven diagnosis of prostate adenocarcinoma Low to intermediate risk National Comprehensive Cancer Network (NCCN) disease TX-T2c-8th addition staging PSA<20 ng/ml Grade group 3 or less Proper rectal space replacement required as determined by the treating radiation oncologist Prostate size less than 60cc defined at time of simulation based on MRI Patient ability to undergo MRI and documented dominant Prostate Imaging Reporting and Data System (PI-RADS) 3 or higher lesion -- Exception is very low risk, low risk, or favorable intermediate risk with a low to intermediate decipher score in which case an SIB is not utilized Androgen-deprivation therapy (ADT) is left to the discretion of the treating radiation oncologist Agreement to use effective contraceptive methods such as condoms and spermicidal foam, intrauterine device, or for their partner to use prescription birth control pills Ability to give informed consent Exclusion Criteria: High risk disease Pelvic lymph node involvement Prophylactic lymph node irradiation requirement as determined by the treating radiation oncologist Evidence of clinical or radiological extracapsular extension or seminal vesicle invasion Prior radiation to the pelvis Prior malignancies within the last 5 years Inability to meet pre-specified 2 fraction DVH constraints Prostate size > 60cc as measures at treatment planning MRI Active significant inflammatory bowel disease (IBD) or rheumatological disease Prior prostate surgeries Previous uro lift Transurethral resection of the prostate (TURP) within 6 months of SBRT "Reasonable" urinary, bowel, and erectile function as defined by the pre-treatment EPIC questionnaire (>50 overall summary score for each domain) Men of reproductive potential may not participate unless they agree to use an effective contraceptive method