Adaptive Stereotactic Body Radiation Therapy to the Prostate and Pelvic Nodes With Simultaneous Integrated Boost to the MR-detected Nodule for Patients With High-risk and Unfavorable Intermediate-risk Prostate Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Adaptive Stereotactic Body Radiation Therapy to the Prostate and Pelvic Nodes With Simultaneous Integrated Boost to the MR-detected Nodule for Patients With High-risk and Unfavorable Intermediate-risk Prostate Cancer (NCT05628363), a na na study. The primary outcome is Number of Participants With Acute Grade ≥3 GI and GU Adverse Events.

2. Clinical Question

3. Trial Design

This is a prospective, single-group clinical trial sponsored by Washington University School of Medicine. The registry lists an enrollment of 28 and identifies the study as active, not recruiting. The recorded start date is 2023-01-18, and the primary completion date is 2025-10-25. The study is listed as not applicable for phase. It has no allocation to treatment groups and no masking.

The study focuses on the safety and feasibility of adaptive prostate SBRT encompassing the whole pelvis, with a tumor boost to sites of disease detected by magnetic resonance imaging. The intervention description includes adaptive stereotactic body radiotherapy, androgen deprivation therapy, and the Ethos Varian treatment system. The treatment arm description specifies pelvic-node radiation of 25 Gy in 5 once or twice weekly fractions and a simultaneous integrated boost to the prostate and proximal seminal vesicles of 36.25 Gy in 5 fractions. The description is truncated after noting that full seminal vesicles are included if involved; further treatment details are not reported in the registry record.

Because there is one treatment group and no masking, the design is not a blinded or randomized comparison. This is relevant when interpreting both safety observations and any future outcome estimates: there is no concurrent control group in the registry record against which to distinguish the treatment experience from other influences. The posted record describes the study’s aim and planned outcomes, but does not provide the primary endpoint result or an analysis of treatment effects.

Several secondary outcomes are listed, including changes in patient-reported quality of life measured by EPIC-26, changes in global function measured by EQ-5D-5L, acute grade 3 or higher adverse events at least possibly related to radiotherapy, and acute GI and GU adverse events below grade 3. The registry record lists 11 outcome measures in total. Details of the other measures and their results are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Participants who received at least 1 fraction of adaptive SBRT.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Acute Grade ≥3 GI and GU Adverse Events, measured over From start of radiotherapy through 90 days after start of radiotherapy.

The primary endpoint is the number of participants with acute grade 3 or higher GI and GU adverse events. It is a count of participants with an event, not a count of all event episodes. The registry defines the population as participants who received at least 1 fraction of adaptive SBRT. The stated observation period runs from the start of radiotherapy through 90 days after the start of radiotherapy.

This endpoint is used to address the trial’s stated safety and feasibility aim. Adverse-event grade conveys severity under the cited CTCAE version 5 framework; the study’s brief summary focuses on the occurrence of acute grade 3 or higher GU or GI events. Counting participants makes the outcome interpretable as how many people in the treated population experienced an event meeting the endpoint definition. It does not, by itself, describe the number, duration, or full clinical course of events in each participant.

The brief summary states a hypothesis of fewer than 15% of patients experiencing an acute CTCAE version 5 grade 3 or higher GU or GI adverse event. The primary outcome title, however, does not establish whether GI and GU events are combined into a single participant-level endpoint, counted separately, or handled in another way when a participant has more than one event. The operational definition beyond the outcome title, population, and timeframe is not reported in the registry record. No primary endpoint result is reported, so the proportion or count observed for this outcome cannot be described from the posted record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What the endpoint counts. The primary outcome is defined as a count of participants with acute grade 3 or higher GI and GU adverse events. This is a binary participant-level outcome for analysis: each eligible participant either meets the endpoint definition or does not. General statistical explanation: a participant-level count differs from an event count, because one participant may experience more than one event. A participant-level outcome avoids treating multiple events in one person as if they came from separate people, but the registry record does not explain how multiple GI or GU events in the same participant are combined for this endpoint.

Who is included. The outcome population is participants who received at least 1 fraction of adaptive SBRT. The record lists enrollment of 28, while the adverse-event information lists 25 participants at risk in the SBRT group. These figures refer to different recorded fields and do not, on their own, establish the number included in the primary endpoint analysis. The primary analysis denominator, the number with endpoint data, and the handling of participants who did not receive treatment or lacked follow-up are not reported in the registry record.

Time window and event grading. The primary outcome timeframe begins at radiotherapy start and extends through 90 days after radiotherapy starts. The brief summary identifies CTCAE version 5 and describes a grade 3 or higher threshold. General statistical explanation: a prespecified follow-up window makes clear which events can contribute to an endpoint, while an event outside that window would not meet that time-based definition. The registry does not further describe event adjudication, attribution rules for the primary endpoint, or how dates and repeated events are handled.

Single-group estimation. This study has one group and no allocation to a comparator. General statistical explanation: a single-group estimate can describe the frequency of an outcome in the observed cohort, provided the denominator and outcome ascertainment are clear. It does not estimate a randomized difference between treatment groups. Comparisons with external experience would require additional data and assumptions that are not part of the reported design. No primary endpoint estimate is posted in the registry record, so there is no result to assess for precision or compatibility with the stated hypothesis.

Uncertainty and confidence intervals. A confidence interval is a range of values generated by a statistical procedure to express uncertainty around an estimate. General explanation: narrower intervals generally indicate greater precision under the assumptions of the method; wider intervals indicate less precision. The registry record does not report a confidence interval for the primary endpoint or a method for calculating one. It also does not report a statistical test or other inferential analysis for that endpoint. A hypothesis threshold in a trial summary is not itself a statistical result: interpretation would require the observed endpoint data and an analysis plan or an explicitly described estimation method.

Planning illustrations. Any planning illustrations based on an observed effect are not observations from the trial and are not evidence of achieved power. General statistical explanation: sample-size planning depends on assumptions about the effect to detect, the significance level, allocation, and statistical method. The registry record describes a planning approach using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a fraction of an observed effect. That planning description is not the design of this clinical trial, which is single-group. The source observed effect and numerical planning results are not reported in the registry record. The planning description therefore should not be read as a trial-specific sample-size justification or as a statement about the precision of this cohort’s endpoint estimate.

Over-dispersion and binary outcomes. General statistical explanation: over-dispersion arises when observed variability exceeds what a chosen statistical model assumes. It is most directly relevant to certain count models and can make standard errors too small if ignored. The primary endpoint is described as a participant count with an event, rather than as a rate of repeated events, and no model is reported. It is therefore not possible to say whether over-dispersion was assessed or relevant to the sponsor’s analysis. The record does not report a statistical analysis plan or any model specification.

Multiplicity and outcome families. The registry lists 11 outcome measures, including several secondary outcomes, but it does not report how multiple outcomes or analyses are handled. General statistical explanation: testing multiple outcomes can increase the chance that at least one result appears notable by chance, and methods such as a prespecified hierarchy or adjustment can address that issue depending on the objective. Whether any such approach was planned or used is not reported in the registry record. The number of analyses listed is 0, so the posted record contains no reported analysis results on which to evaluate multiplicity procedures.

What the reported adverse-event fields represent. The record gives participant counts at risk and affected for serious and other adverse events, along with selected serious-event terms. General statistical explanation: broad adverse-event summaries and a narrowly defined primary endpoint answer different questions. A serious-event category does not automatically correspond to grade 3 or higher GI/GU toxicity, and a listed event term does not establish that it occurred within the primary endpoint window or was related to radiotherapy. The posted fields do not provide the event-level detail needed to reconstruct the primary outcome.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Adaptive Stereotactic Body Radiotherapy (SBRT)")
n      <- c(25)
events <- c(1)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Adaptive Stereotactic Body Radiotherapy (SBRT)  25  1  4.0  0.1  20.4  0.7  19.5  0.9  19.6

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 11 outcome measures, with the primary outcome focused on acute grade 3 or higher GI and GU adverse events and secondary outcomes covering quality of life, global function, and other adverse-event categories. It reports 0 analyses. A statistical plan describing the hierarchy of outcomes, multiplicity adjustment, or which endpoints would be treated as confirmatory is not reported in the registry record. General statistical explanation: when several outcomes are examined, interpretation depends in part on whether the analyses were prespecified and whether the chance of false-positive findings across outcomes was addressed. The record does not establish what approach, if any, was intended.

The primary endpoint population consists of participants who received at least 1 fraction of adaptive SBRT. The registry does not report how many participants met this criterion, how many had complete endpoint follow-up, or how missing endpoint information was handled. It also does not report whether participants were analyzed according to treatment received, assigned treatment, or another analysis population. Because this is a single-group design, there is no randomized allocation population described.

The record does not state how withdrawals, incomplete follow-up, or events with uncertain grading or attribution would be treated. No imputation method, sensitivity analysis, or missing-data assumption is reported. General statistical explanation: missing data can affect an outcome estimate if participants without observed information differ from those with complete data, especially when their unobserved outcomes are related to their likelihood of remaining under observation. Without counts and a stated handling strategy, the direction or magnitude of any such influence cannot be assessed.

These gaps mean that the registry record does not support an assessment of the primary endpoint’s analysis population, missing-data robustness, or multiplicity control. A future interpretation would require those details alongside the endpoint result.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: atrial fibrillation (4.0%), hyperglycemia (4.0%), death nos (4.0%).

The adverse-event record lists one group, Adaptive Stereotactic Body Radiotherapy (SBRT). It reports 25 participants at risk for serious adverse events, with 2 affected, and 25 at risk for other adverse events, with 24 affected. It also records 1 death. These are broad safety counts, not the primary endpoint result. They do not identify which participants had acute grade 3 or higher GI or GU events, whether events fell within the primary timeframe, or whether they were attributed to radiotherapy.

The listed top serious adverse-event terms are atrial fibrillation, hyperglycemia, and Death NOS, each reported as 4.0%. These terms are registry listings, not a complete clinical account of event timing, duration, severity, or causal relationship. The record does not clarify whether the death listed among serious terms corresponds to the separately recorded death count, and the figures should not be combined or reinterpreted as a primary endpoint rate.

General statistical explanation: adverse-event summaries depend on the definitions used for seriousness, severity, attribution, and the period of observation. Seriousness and grade are distinct concepts, so a serious event is not automatically equivalent to a grade 3 or higher event. The registry record does not provide enough detail to map these broad counts to the acute GI/GU endpoint. The primary endpoint results are not reported in the registry record.

13. What the Result Does, and Does Not, Mean

The record describes a prospective study intended to evaluate the safety and feasibility of adaptive whole-pelvis prostate SBRT with a boost to MR-detected disease. It specifies the treatment group, a primary acute GI/GU adverse-event outcome, and the outcome’s follow-up window. It also lists broad adverse-event counts and selected serious-event terms. These details describe the study’s design and recorded safety information, but they do not provide the primary endpoint result.

The stated hypothesis is that fewer than 15% of patients will experience an acute CTCAE version 5 grade 3 or higher GU or GI adverse event. That statement is a hypothesis, not a finding. Without the observed number of participants meeting the endpoint, the relevant denominator, and an estimate of uncertainty, the posted record cannot show whether the hypothesis was supported. Nor can the broad serious and other adverse-event counts substitute for the primary endpoint, because they do not identify the required grade, organ system, and timeframe.

Even if a primary endpoint result becomes available, the single-group design would describe outcomes in this cohort rather than establish a randomized comparative effect. There is no concurrent control group listed. Differences from results in other studies would not by themselves establish that the treatment caused a difference, because populations, follow-up, event definitions, and other conditions may differ. Those comparisons and their assumptions are not reported in the registry record.

The listed enrollment of 28 does not, on its own, establish the number analyzed for the endpoint. The endpoint population requires receipt of at least 1 fraction of adaptive SBRT, and the number meeting that criterion or with complete endpoint data is not reported. The record also does not describe missing-data handling or an analysis plan. These omissions prevent assessment of the denominator and precision of a primary endpoint estimate.

Accordingly, the posted information can be read as a study description with some general adverse-event reporting, but not as a completed statistical evaluation of the primary safety question. It does not establish that the treatment is safe, unsafe, feasible, or infeasible. The primary result and the analytical details needed to interpret it are not reported in the registry record.

14. Why This Trial Matters Statistically

This trial raises a statistical question about how to describe acute toxicity after a specialized radiotherapy approach in a defined cancer population. Its primary outcome is framed as a participant-level count of acute grade 3 or higher GI and GU adverse events, with a stated observation period and a population defined by receipt of at least 1 treatment fraction. These features matter because an interpretable safety estimate depends on a clear outcome definition, a clear denominator, and adequate follow-up for the event window.

The design also illustrates a distinction between feasibility or safety monitoring and comparative effectiveness. A single-group study can document events in participants treated under the study approach, but it has no randomized control group for estimating a treatment difference. Statistical interpretation must therefore stay close to the observed cohort and avoid treating the study as if it directly compared alternative care.

The registry record lists multiple outcomes, including patient-reported quality of life, global function, and additional adverse-event measures. This broad outcome set can offer several kinds of information, but analysis choices matter when multiple outcomes are considered. The record does not report a statistical plan for prioritizing or adjusting analyses, and it reports no analyses. This limits what can be concluded from the posted results.

Most importantly, the registry record does not report the primary outcome result, its denominator, or an uncertainty estimate. That absence makes it impossible to assess the stated safety threshold from the posted information. The broad adverse-event counts cannot fill that gap because they do not identify the primary endpoint’s grade, organ system, and timeframe. The study’s statistical importance therefore lies in the question it is designed to address and in the need for transparent endpoint reporting; the available record does not yet answer that question.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The principal limitation for statistical interpretation is that the primary endpoint result is not reported in the registry record. There is no posted count of participants meeting the acute grade 3 or higher GI/GU definition, no endpoint denominator, and no confidence interval or inferential analysis. The registry lists an enrollment of 28, but the primary endpoint population is defined by receipt of at least 1 fraction of adaptive SBRT; the number in that population is not reported.

The endpoint title does not clarify whether GI and GU events are combined into one participant-level outcome, assessed separately, or counted under another rule when a participant has events in both systems. Further details of event ascertainment, severity classification, attribution, and handling of repeated events are not reported. These uncertainties limit the ability to reproduce or independently interpret the endpoint definition.

The single-group design has no concurrent comparator arm. This prevents a randomized estimate of the difference between the study treatment and another approach. The registry also does not report a statistical analysis plan, a rationale for the enrollment target, interim analyses, missing-data procedures, or a method for handling multiple outcomes. The planning description in the record is an illustration based on an observed effect, not a trial-specific design justification, and it does not supply evidence of observed power.

The adverse-event record is not a substitute for primary outcome reporting. Its serious and other event counts and selected serious terms do not identify whether events were acute, grade 3 or higher, GI or GU, or within the specified primary timeframe. The record does not provide detail connecting these broad fields to the primary endpoint. Results for the listed secondary outcomes are also not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Adaptive Stereotactic Body Radiation Therapy to the Prostate and Pelvic Nodes With Simultaneous Integrated Boost to the MR-detected Nodule for Patients With High-risk and Unfavorable Intermediate-risk Prostate Cancer — NCT05628363.
• Registry record last updated 2026-07-02; status last verified 2026-06.
• Results first posted 2026-07-02.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT05628363 is a prospective, single-group study sponsored by Washington University School of Medicine. It evaluates adaptive stereotactic body radiotherapy to the prostate and pelvic nodes, with a simultaneous integrated boost to an MR-detected nodule, in patients with high-risk or unfavorable intermediate-risk prostate cancer. The registry lists enrollment of 28, a start date of 2023-01-18, a primary completion date of 2025-10-25, and status active, not recruiting.

The primary outcome is the number of participants with acute grade 3 or higher GI and GU adverse events from radiotherapy start through 90 days after start, among participants who received at least 1 fraction of adaptive SBRT. The registry record states a hypothesis of fewer than 15% experiencing an acute CTCAE version 5 grade 3 or higher GU or GI adverse event. It does not report the primary endpoint result, its analysis denominator, or an uncertainty estimate.

The record lists 11 outcome measures and 0 analyses. Its adverse-event information includes 2 participants affected by serious adverse events among 25 at risk, 24 affected by other adverse events among 25 at risk, and 1 death. These broad figures do not establish the primary acute GI/GU outcome.