This clinical trial studies the side effects of computed tomography (CT)-guided stereotactic body radiation therapy (SBRT) with intrafraction motion monitoring and to see how well it works in treating patients with prostate cancer that has not spread to other parts of the body (localized). In CT-guided SBRT, x-ray-based imaging and cone-beam CTs are used to define and localize the area to be treated with SBRT. SBRT is a type of external radiation therapy that uses special equipment to position a patient and precisely deliver radiation to tumors in the body (except the brain). The total dose of radiation is divided into smaller doses given over several days. This type of radiation therapy helps spare normal tissue. A recent randomized trial showed that while SBRT is associated with less urinary incontinence and erectile dysfunction than complete surgical removal of the prostate, there are more urinary irritative side effects and more bowel side effects than with surgery. One source of uncertainty in SBRT that may contribute to genitourinary (GU) and gastrointestinal (GI) side effects is the necessity of treating a "margin" of volume around the prostate to account for its movement during SBRT. Intrafraction motion monitoring is any technique or system designed to track the movement of the body and target during fractions of external beam radiation to keep the beam on target. This allows for the patient to be repositioned, if needed, to ensure delivery of the SBRT to only the planned treatment area. CT-guided SBRT with intrafraction motion monitoring may lower GU and GI side effects by allowing tighter margins, as has been demonstrated with magnetic resonance imaging (MRI)-guided SBRT.
Histologically confirmed, clinically localized adenocarcinoma of the prostate
No evidence of metastatic disease in lymph nodes above the bifurcation of the renal arteries, or in bones or visceral organs (nodal disease identified on a prostate-specific membrane antigen [PSMA] positron emission tomography [PET]/CT scan below the bifurcation of the renal arteries are amenable)
Staging workup as recommended by the National Comprehensive Cancer Network (NCCN) on the basis of risk grouping
Advanced imaging studies (i.e. PSMA PET/CT and fluciclovine PET/CT scan) can supplant a bone scan if performed first
Patients with neuroendocrine or small cell carcinoma of the prostate
Patients with any evidence of distant metastases except that evidence of lymphadenopathy below the level of the renal arteries can be deemed locoregional per the discretion of the investigator
Prior whole gland cryosurgery, high-intensity focused ultrasound (HIFU) or brachytherapy of the prostate
Prior pelvic radiotherapy
Single group
Biospecimen Collection
Procedure/SurgeryUndergo blood sample collection
Computed Tomography
Procedure/SurgeryUndergo CT
CT-guided Stereotactic Body Radiation Therapy
RadiationUndergo CT-guided SBRT with intrafraction motion monitoring
Intrafraction Motion Monitoring
Other interventionUndergo CT-guided SBRT with intrafraction motion monitoring
Magnetic Resonance Imaging
Procedure/SurgeryUndergo MRI
Questionnaire Administration
Other interventionAncillary studies
Incidence of acute grade ≥ 2 genitourinary (GU) toxicities
Will determine physician-scored GU toxicities by the Common Terminology Criteria for Adverse Events, version 5 (CTCAE v5.0) criteria. Rates will be reported descriptively. Point estimates as well as the associated 95% confidence intervals will be reported.
Incidence of acute grade ≥ 2 gastrointestinal (GI) toxicities
Will determine the physician-scored GI toxicities by the CTCAE v5.0 criteria. Rates will be reported descriptively. The analysis of GI toxicity will be stratified for use of hydrogel spacers or not, as these may reduce both acute and late GI toxicity, and by use of nodal radiotherapy or not, if event rate permits this analysis. Additionally, separate analyses of these secondary endpoints stratifying patients by treatment platform and receipt of online adaptive radiotherapy will be performed.
Cumulative incidence of late grade ≥ 2 GU and GI toxicities
Will determine the physician-scored GU and GI toxicities by the CTCAE v5.0 criteria. Will be analyzed using a cumulative incidence framework. The analysis of GI toxicity will be stratified for use of hydrogel spacers or not, as these may reduce both acute and late GI toxicity, and by use of nodal radiotherapy or not, if event rate permits this analysis. Additionally, separate analyses of these secondary endpoints stratifying patients by treatment platform and receipt of online adaptive radiotherapy will be performed.
Change in International Prostate Symptom Score (IPSS) and Expanded Prostate Cancer Index Composite-26 (EPIC-26) score
A 15-point or greater increase in IPSS will be considered clinically relevant. Clinically relevant decrement in EPIC-26 domains will be defined as greater than 18, 14, 12, and 24 points for urinary incontinence, urinary irritative or obstructive, bowel, and sexual domains, respectively. Analysis will be performed using a restricted maximum likelihood-based mixed models repeated measures approach. The model will include the fixed categorical effects of treatment, time, and treatment-by-time interaction, as well as the other fixed baseline covariates. An unstructured covariance structure will be used to model the within-patient errors. The Kenward-Roger approximation will be used to estimate denominator degrees of freedom. The analysis of both acute and late changes in the bowel domain of the EPIC instrument will be stratified for use of hydrogel spacers or not, as these may reduce both acute and late GI bowel symptoms.
Biochemical recurrence-free survival
Biochemical recurrence will be defined as serum prostate-specific antigen (PSA) levels that are 2 ng/mL higher than the nadir PSA achieved after SBRT. Will be estimated by the Kaplan-Meier method as well as descriptively (mean, standard deviation, median, first and third quartiles, minimum, maximum).
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Jonsson Comprehensive Cancer Center
Lead sponsor
Varian Medical Systems
Collaborator
