The goal of this clinical trial is to determine the safety of stereotactic body radiation therapy (SBRT) microboost technique in patients with low to intermediate risk prostate cancer. The main question it aims to answer is: Is microboost SBRT with whole gland de-escalation both safe and effective in managing patients with low to intermediate-risk prostate cancer while maintaining acceptable toxicity levels? All patients will receive microboost SBRT at a dose of 45 Gy delivered in 5 fractions in up to 4 MRI-defined lesions. Patients (Arm 1) with highest grade disease in the microboost target lesion in the absence of GG2-3 beyond the microboost target (only GG1 disease can be present outside of the microboost region) will receive whole gland de-escalation at a dose of 30 Gy delivered in 5 fractions. Patients (Arm 2) with highest grade disease outside of the target lesion will receive whole gland de-escalation at a dose of 35 Gy delivered in 5 fractions. Participants will be treated every other day over a two week period and then follow up after radiation treament for up to 5 years. Participants will be asked to complete questionnaires and provide blood and urine samples for research purposes.
Patients age 18 or older.
Patients with an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2
Patients with histologically confirmed adenocarcinoma of the prostate who have not received prior pelvic radiation therapy or prostatectomy.
cT1-cT2a (AJCC; 8TH edition, 2017)
Patients with evidence of disease Grade Group 4 (GG4) or higher.
Patients with PSA >20 ng/mL.
Patients with evidence of clinical stage T3a+ or gross extracapsular extension on the diagnostic MRI.
Patients who received prior or concurrent androgen deprivation therapy for prostate cancer.