The goal of this clinical trial is to evaluate if adaptive stereotactic body radiation therapy (SBRT) is a safe and effective way to treat prostate cancer in adults. It will assess the safety profile of adaptive SBRT over time.
The main questions this trial aims to answer are:
* What is highest dose of adaptive SBRT without causing serious side effects? * Can adaptive SBRT more precisely targeting the prostate while reducing radiation exposure to nearby organs? * What side effects do participants experience during treatment, right after treatment, and over the five years post-treatment? * Can adaptive SBRT reduce urination-related side effects and support quality of life during and after treatment?
Participants will:
* Receive adaptive SBRT treatment every other day, for a total of 5 treatment sessions (called fractions). The full course of treatment typically takes 2 to 3 weeks. * Have a follow-up phone call about 6 weeks after treatment to check on side effects and overall wellbeing. * Visit the clinic for check-ups and tests:
* At 90 days (about 3 months) after treatment * Then every 3 months for the first year * Then every 6 months after that
Subjects must have histologically confirmed intermediate- and favorable high risk (AJCC 8th ed stage IIA-IIC) adenocarcinoma of the prostate.
Age > 18 years.
ECOG performance status ≤ 2
Prostate volume (segmented) ≤ 100 cc determined by MRI and/or US within 24 mo of treatment for patients not on ADT and within 6 mo for patients on prior ADT. A simulation MRI is acceptable.
Subjects must not be experiencing toxicity CTCAE grade ≥ 3 GU or GI toxicity at baseline.
Subjects must not be receiving any other investigational agents.
Subjects must not have had prior pelvic radiation therapy.
Subjects must not have node-positive disease.