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 radiationoncologist

• Prostate size less than 60cc defined at time of simulation based on MRI

• Patient ability to undergo MRI and documented dominant Prostate Imaging Reportingand Data System (PI-RADS) 3 or higher lesion

-- Exception is very low risk, low risk, or favorable intermediate risk with a lowto intermediate decipher score in which case an SIB is not utilized

• Androgen-deprivation therapy (ADT) is left to the discretion of the treatingradiation oncologist

• Agreement to use effective contraceptive methods such as condoms and spermicidalfoam, intrauterine device, or for their partner to use prescription birth controlpills

• Ability to give informed consent

Exclusion Criteria:

• High risk disease

• Pelvic lymph node involvement

• Prophylactic lymph node irradiation requirement as determined by the treatingradiation oncologist

• Evidence of clinical or radiological extracapsular extension or seminal vesicleinvasion

• 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-treatmentEPIC questionnaire (>50 overall summary score for each domain)

• Men of reproductive potential may not participate unless they agree to use aneffective contraceptive method