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.
PRIMARY OBJECTIVE: I. To determine the acute physician-scored GU toxicity associated with CT-guided SBRT utilizing a 2mm prostate ± seminal vesicles planning target volume (PTV) margin for localized prostate cancer. SECONDARY OBJECTIVES: I. To determine the acute physician-scored GI toxicity associated with the intervention. II. To determine the late physician-scored toxicity associated with the intervention. III. To determine the patient-reported quality of life outcomes associated with the intervention. IV. To determine the 5-year biochemical recurrence-free survival (BCRFS) associated with the intervention. V. To evaluate intrafraction prostate motion using on-board imaging data acquired during this trial in conjunction with prior data, described above. OUTLINE: Patients undergo CT-guided SBRT with intrafraction motion monitoring over 5 fractions every other day, or on consecutive days, if necessary, in the absence of disease progression or unacceptable toxicity. Patients also undergo CT and MRI on study and blood sample collection throughout the study. After completion of study treatment, patients are followed up at 1 and 3 months, every 3 months for the first year, every 6 months for a minimum of 5 years, and then annually thereafter.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
80
Undergo blood sample collection
Undergo CT
Undergo CT-guided SBRT with intrafraction motion monitoring
Undergo CT-guided SBRT with intrafraction motion monitoring
Undergo MRI
Ancillary studies
UCLA / Jonsson Comprehensive Cancer Center
Los Angeles, California, United States
RECRUITINGIncidence 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.
Time frame: From the start of stereotactic body radiation therapy (SBRT) to 90 days post-SBRT
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.
Time frame: From the start of SBRT to 90 days post-SBRT
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.
Time frame: Up to 5 years post-SBRT
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.
Time frame: Baseline to 5 years post-SBRT
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).
Time frame: Up to 5 years post-SBRT
Intrafraction prostate motion
Will evaluate intrafraction prostate motion using on-board imaging data acquired during this trial, as well as imaging data from previously treated patients who received computed tomography-guided SBRT. Analysis of imaging data acquired during this study will be descriptive and exploratory.
Time frame: Baseline, at time of SBRT
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