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