Evaluation of Single Session Stereotactic Body Radiotherapy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Single Session Stereotactic Body Radiotherapy (NCT00492817), a na phase 1, phase 2 study. The primary outcome is Complete Pain Relief Using Stereotactic Body Radiotherapy (SBRT) to Treat Spine and Para- Spinal Tumors in a Single Session.

2. Clinical Question

The broader stated aims include assessing safety and efficacy, documenting pain, symptoms, symptom interference and quality of life before and after treatment, and recording changes in neurological function at defined intervals relative to pretreatment function. Those aims describe what the research sought to assess; they do not establish what the observed outcomes were. The registry lists three outcome measures, but the posted results do not include values for the primary endpoint or enough detail to evaluate the other outcomes.

3. Trial Design

The registry identifies this as a Phase I/II evaluation of single-session SBRT for spinal or paraspinal metastases. It records a single-group model, allocation marked NA, and no masking. The intervention is a procedure, and the arm is named Single Session Stereotactic Body Radiotherapy (SBRT). There is no separate control arm in the record, so the design does not provide a direct randomized comparison between treatment strategies.

The enrollment recorded is 71. The study start date is 2005-10-13, and the primary completion date is 2024-11-27. The registry status is completed. These record details describe enrollment and study status; they do not show how many participants contributed data to each outcome or assessment. Those analysis-population details are not reported in the registry record.

The arm description says a CT scan using CT-on-Rails in the same treatment room, immediately before radiation treatment, would be performed on day 1. The record’s stated objectives also include documenting pain and related symptoms, quality of life, and neurological function before and after treatment. The specific assessment schedule beyond the primary endpoint timeframe, the treatment delivery details beyond the arm description, and the protocol-defined eligibility criteria are not reported in the registry record.

The primary endpoint is defined at six months after completion of radiation therapy. The registry does not report a comparator, masking procedures, or an allocation mechanism beyond the entries above. It also does not report the protocol’s sample-size justification, any interim-analysis plan, or a full statistical analysis plan. The Phase I/II label alone does not specify these design features or establish how the results should be interpreted.

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

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 Complete Pain Relief Using Stereotactic Body Radiotherapy (SBRT) to Treat Spine and Para- Spinal Tumors in a Single Session, measured over Six months after completion of radiation therapy.

The primary endpoint is complete pain relief six months after completion of radiation therapy. It is measured as a count of participants, and the endpoint description defines complete relief as a “pain worst” score of zero on the BPI at the six-month assessment. This is a binary classification at the participant level: a participant either meets the stated zero-score definition or does not.

Complete pain relief is a clinically interpretable outcome because it focuses on an explicitly defined symptom state rather than only a change in an average score. The definition matters: it is not the same as any improvement in pain, a reduction from baseline, or a favorable change in a quality-of-life measure. Those would be different outcomes. General statistical interpretation requires keeping the endpoint definition, timing, and population together, since each affects what the reported count would describe.

The registry specifies the endpoint and its timeframe but does not report the observed count, the denominator assessed at six months, or an estimate of uncertainty. It also does not report how missing BPI assessments were handled. Consequently, the endpoint’s observed frequency and precision cannot be assessed from the posted results. The definition alone is not evidence about how many participants achieved complete relief.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods determine how observations are turned into estimates and how much uncertainty surrounds those estimates. In this record, the primary outcome is specified as a count of participants meeting a binary definition: a zero “pain worst” BPI score six months after completion of radiation therapy. That endpoint definition is distinct from a statistical result. The posted results do not report the count meeting the definition, the number assessed, or an estimate with uncertainty, and the registry lists zero analyses.

What does a count describe?

For a binary endpoint, a count describes how many observed participants met the endpoint definition in the analyzed population. Interpreting that count requires knowing who was eligible for the assessment and who had data available. If the denominator is also reported, the count can be understood relative to the assessed group. For this primary endpoint, neither the observed count nor the six-month denominator is reported in the registry record. The enrollment figure of 71 is not a substitute for a reported endpoint denominator.

A confidence interval is a statistical range that expresses uncertainty around an estimate under the assumptions of the method used. It is not a guarantee that the true value lies within the interval, and its width depends on factors such as the amount of information and the method. No confidence interval for the primary endpoint is reported in the registry record. Without an endpoint estimate and its uncertainty, the precision of the result cannot be judged.

What can a single-group design establish?

General statistical interpretation distinguishes description from comparison. A single-group study can describe outcomes observed among participants receiving the intervention. It does not, by itself, supply the concurrent counterfactual outcome that a separate control group would help estimate. Because the registry lists a single-group model and no allocation, there is no randomized treatment contrast to interpret. The record’s stated goals include safety and efficacy, but the design entry alone does not establish a comparative treatment effect.

Changes from pretreatment assessments can be informative descriptions if baseline and follow-up measurements are collected and analyzed. However, change over time may also reflect influences other than the intervention. The posted results do not report the relevant change estimates or the methods used to analyze them. No adjustment strategy, model specification, or covariate plan is reported in the registry record.

Why do analysis populations matter?

An analysis population identifies which participants contribute to a particular estimate. It may depend on eligibility, treatment receipt, outcome availability, and the analysis rules. Those definitions should not be assumed from enrollment alone. The registry does not report the population used for the primary endpoint, the number with six-month data, or the handling of participants with missing assessments. As a result, it is not possible to tell whether the endpoint estimate would represent everyone enrolled or only a subset with available data.

Missing data can affect both the number analyzed and the interpretation of an estimate. General methods may use explicit assumptions about why values are missing, but the appropriateness of an approach depends on the data and the analysis plan. The registry record does not report the extent or reasons for missing primary endpoint data, or any imputation or sensitivity-analysis methods. No particular missing-data assumption should be attributed to the study.

How should planning calculations be read?

The planning description states that its illustrations use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also says the effect to detect is a stated fraction of the observed effect. For time-to-event calculations, it describes the output as the total number of events using the Schoenfeld method; for other calculations, it describes participants per arm. These are planning assumptions, not a description of the actual single-group design, and they do not constitute observed power.

The planning description says the effect is based on an observed effect, but the primary outcome result is not reported in the registry record. Therefore the observed effect and the basis for evaluating any such illustration cannot be checked from the posted results. No sample-size justification from the trial protocol is reported. A planning calculation cannot fill the gap left by absent outcome data or create a treatment comparison that the study design did not include.

General statistical concepts such as over-dispersion apply to count outcomes when variability exceeds what a simple model assumes. Accounting for over-dispersion can alter uncertainty estimates and inference. The primary outcome is described as a count of participants, but no dispersion estimate or count-model analysis is reported. It would be inappropriate to infer that a particular count model or adjustment was used.

The record does not report p-values, confidence intervals, regression estimates, adjustment methods, interim analyses, or a detailed analysis plan. This absence limits what can be said about inferential methods. It does not establish that a method was or was not used outside the registry entry; it means those details are not reported in the registry record.

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("Single Session Stereotactic Body Radiotherapy (SBR")
n      <- c(61)
events <- c(18)
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  Single Session Stereotactic Body Radiotherapy (SBR  61  18  29.5  18.5  42.6  19.6  41.9  19.6  41.9

11. Multiplicity, Missing Data and Analysis Populations

The registry describes three outcome measures and identifies complete pain relief at six months as the primary endpoint. It does not report the results of those measures, and it lists zero analyses. The record does not describe a testing hierarchy, a multiplicity adjustment, or a plan for controlling the chance of false-positive findings across multiple outcomes. These details are not reported in the registry record.

Multiplicity is a general statistical concern when several outcomes or hypotheses are assessed. If many tests are interpreted without a prespecified strategy, the chance of at least one apparently notable result can increase. Methods such as defining a primary endpoint in advance or adjusting inference across tests can address aspects of that concern, but the registry entry does not state whether or how these approaches were used. The existence of several outcome measures alone does not establish that multiple hypothesis tests were performed.

Missing-data handling is also not reported. The record does not give the number of participants assessed for the primary endpoint at six months, the amount or reasons for missing data, or methods for handling missing BPI values. It does not report sensitivity analyses examining how missing outcomes might affect interpretation.

Analysis populations and endpoint-specific denominators are not reported in the registry record. Enrollment of 71 is a study-level figure, not a documented denominator for every outcome. The registry also does not provide a full statistical analysis plan, interim-analysis details, or a protocol-based sample-size justification. In the absence of these details and the outcome results, it is not possible to assess how missingness, multiplicity, or analysis-population decisions may have influenced the reported findings.

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

Serious events with the highest arm-level rate: esophageal stricture (2.8%), diarrhea (2.8%), nephrostomy tube placement, malfunctioning prostomy (1.4%), hemorrhage (1.4%), neroforaminal stenosis and nerve root compression (1.4%).

The registry records 7 participants with serious adverse events among 71 at risk in the SBRT group. It records 0 participants with other adverse events among 71 at risk and reports 63 deaths. These entries should be read as separate recorded counts. The count of deaths does not, by itself, establish that the deaths were caused by treatment or indicate when they occurred.

The registry lists serious-event terms with percentages: Esophageal stricture, 2.8%; Diarrhea, 2.8%; Nephrostomy tube placement, Malfunctioning prostomy, 1.4%; Hemorrhage, 1.4%; and Neroforaminal stenosis and nerve root compression, 1.4%. The record does not report the denominator or counting rules underlying each percentage, and it does not clarify whether participants could contribute to more than one listed term. These percentages should therefore be read as registry-listed figures, not converted into counts or added together.

The timeframe for safety collection, event severity criteria beyond the serious-event category, and the relationship of events to the intervention are not reported in the registry record. The figures describe what the registry records; they do not alone establish causation, comparative safety, or the completeness of event ascertainment.

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

The record establishes that the study evaluated single-session SBRT in a single-group Phase I/II design and specified complete pain relief six months after radiation as its primary endpoint. It also records enrollment and selected adverse-event and death counts. These details describe the research question and some safety reporting, but they do not provide the missing primary outcome result.

The posted results do not show how many participants had a zero “pain worst” BPI score at six months, how many were assessed then, or how precise an estimate would be. Accordingly, the record does not support a statistical conclusion about the frequency of complete pain relief. Nor does the absence of a reported endpoint value show that no participant achieved it; the outcome result is simply not reported in the registry record.

The design limits comparative interpretation. A single group without a separate randomized comparator can describe outcomes in the treated group, but it cannot directly establish how those outcomes differ from an alternative. The registry’s stated goal of assessing safety and efficacy is not itself a result, and the design label does not establish a causal effect.

The safety figures likewise require restraint. The registry reports serious adverse events, other adverse events, and deaths as separate counts, but does not report the timing or treatment relationship of these events. They should not be interpreted as evidence that the intervention caused an event or death. The listed event percentages also cannot be translated into a more detailed risk estimate without reported denominators and counting rules.

Planning illustrations, if considered, address hypothetical design questions under stated assumptions; they are not evidence of an observed effect or observed power. In particular, they cannot replace outcome estimates and uncertainty. The defensible reading is therefore narrow: the record describes the study design and endpoint and includes selected safety counts, while the primary efficacy result, analysis details, and comparative evidence are not reported.

14. Why This Trial Matters Statistically

This trial is statistically notable because its primary endpoint is defined in a direct, participant-level way: complete pain relief means a zero “pain worst” BPI score at a specified follow-up. Clear definitions help readers distinguish complete relief from partial improvement or change in a continuous score. The endpoint’s timing also matters, since the record places assessment six months after completion of radiation therapy.

The single-group structure is equally important. It clarifies that the record does not present a randomized comparison, so the study question and the conclusions it can support are not the same as those from a controlled treatment comparison. A descriptive outcome in a treated group is not automatically a comparative effect. This distinction is essential when interpreting results in clinical research.

The record also illustrates why an endpoint definition should be accompanied by its observed count, denominator, and uncertainty. Without those pieces, a reader cannot assess how common the endpoint was among assessed participants or how precisely it was estimated. Enrollment of 71 does not establish how many participants contributed data to the primary endpoint at six months.

Safety reporting requires similar care. The listed counts and serious-event terms are useful descriptive entries, but the absence of reported timing, attribution, and term-specific denominator information limits interpretation. A reported death count is not a causal conclusion. Separating event description from causal inference is a core statistical discipline.

Finally, planning assumptions and observed evidence serve different purposes. A planning illustration can show how hypothetical design choices relate to a target effect under stated assumptions, but it is not an observed result and cannot answer the clinical question on its own. The record’s combination of a specified endpoint, single-group design, and absent primary outcome result makes transparent reporting of denominators, uncertainty, analysis populations, and missing-data handling especially important.

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 interpreting efficacy is that the registry does not report the primary endpoint result. The count of participants with complete pain relief at six months, the denominator assessed, and any estimate of uncertainty are not reported in the registry record. Without those data, the outcome’s frequency and precision cannot be evaluated.

The single-group design has no separate comparator, and the registry lists allocation as NA and masking as none. Consequently, the record does not provide a randomized comparison with another treatment or control condition. Any observed changes over time, if available elsewhere, would need to be distinguished from influences unrelated to the intervention; the registry does not report outcome estimates or methods for doing so.

Important population details are also not reported in the registry record. These include eligibility criteria, baseline characteristics, endpoint-specific analysis populations, and the number assessed at the six-month visit. The extent and reasons for missing outcome data, and methods used to address missingness, are not reported. This prevents assessment of how representative the analyzed participants would be of those enrolled.

The statistical plan is not detailed in the record. A protocol-based sample-size justification, interim-analysis plan, analysis methods, multiplicity strategy, and definitions of analysis populations are not reported. The planning assumptions described for illustrative calculations do not substitute for the trial’s own design justification or an analysis of observed outcomes.

For safety, the registry gives counts and selected event terms but does not report the safety observation period, event attribution, or the denominator and counting rules for the listed percentages. The relationship and timing of the 63 deaths are not reported. These limitations restrict interpretation of both efficacy and safety and preclude conclusions beyond the record’s descriptive entries.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluation of Single Session Stereotactic Body Radiotherapy — NCT00492817.
• Registry record last updated 2025-10-24; status last verified 2025-10.
• Results first posted 2025-10-24.
• 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

The registry identifies NCT00492817, Evaluation of Single Session Stereotactic Body Radiotherapy, as a completed Phase I/II single-group study sponsored by M.D. Anderson Cancer Center. Enrollment is recorded as 71. The study start date is 2005-10-13, and the primary completion date is 2024-11-27.

The intervention is single-session stereotactic body radiotherapy for spinal or paraspinal metastatic tumors. The primary endpoint is the count of participants with complete pain relief, defined by a zero “pain worst” BPI score six months after radiation therapy. The posted results do not report the endpoint value or its denominator. The registry lists three outcome measures and zero analyses.

Safety entries include 7 participants with serious adverse events among 71 at risk, 0 with other adverse events among 71 at risk, and 63 deaths. Event timing, attribution, and additional analysis details are not reported in the registry record.