This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Stereotactic Radiosurgery (SRS) for Spine Metastases (NCT00593320), a randomized na study. The primary outcome is Pain Control Rate as Measured by the The Brief Pain Inventory.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00593320 |
| Phase | NA |
| Condition | Spinal Metastases |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 2 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Washington University School of Medicine |
| Results posted | Yes |
2. Clinical Question
Population
People with one or two localized spine metastases. The registry record lists spinal metastases as the condition and an enrollment of 2. It also notes that neither participant completed the required primary-outcome questionnaires.
Intervention
Single-fraction stereotactic radiosurgery in the low-dose arm, defined in the arm description as 14 Gy.
Comparator
Single-fraction stereotactic radiosurgery in the high-dose arm, defined as 18 Gy.
Primary question
The planned primary question concerned pain control rate measured with the Brief Pain Inventory at 6 months after completion of treatment. The registry record does not provide a completed comparison of pain control between the arms.
This is a dose-comparison question: whether the recorded pain-control outcome differs between the low-dose and high-dose regimens. The study is listed as randomized, with a parallel model and no masking. Its brief summary describes allocation as like flipping a coin, but details of the randomization process are not reported in the registry record.
The intended endpoint and its assessment time are identified, but the record does not state how a BPI score would be converted into a pain-control rate, what change would count as control, or how incomplete questionnaires would be handled in the primary analysis. Those details matter because an endpoint label alone does not establish the precise statistical comparison. In this record, the primary endpoint cannot answer the dose-comparison question: one participant experienced disease progression and could not continue the questionnaires, while the other was removed for non-compliance and did not complete them.
3. Trial Design
The registry describes a randomized, parallel-group study of stereotactic radiosurgery for one or two localized spine metastases. The low-dose arm is described as single-fraction treatment at 14 Gy, and the high-dose arm as single-fraction treatment at 18 Gy. The brief summary also identifies these dose levels and says that patients would be randomized. The intervention category is radiation.
Masking is listed as none. The record therefore does not describe a blinded comparison. It does not report details such as who generated the allocation sequence, how assignments were concealed before enrollment, or whether outcome assessments were conducted independently of treatment assignment. The phase is listed as NA, and the study kind is listed as other.
The registry gives an enrollment of 2 and identifies Washington University School of Medicine as sponsor. The listed start is 2007-09, and the primary completion date is 2010-03. The status is terminated. The reason for termination and the timing of the termination are not reported in the registry record; the listed primary completion date should not be treated as an explanation of why the study stopped.
The primary outcome is titled Pain Control Rate as Measured by The Brief Pain Inventory, with assessment at 6 months after completion of treatment. Local Control Rate is listed as a secondary outcome. The record also indicates four outcome measures, but does not present a completed primary comparison or a primary analysis. These design details describe the intended comparison, not evidence that either dose produced a particular outcome.
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
| Stage | Arm 1: Low Dose | Arm 2: High Dose |
|---|---|---|
| STARTED | 1 | 1 |
| COMPLETED | 1 | 1 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: One patient experienced disease progression and was unable to continue to complete the required questionnaires. The second patient was removed from study due to non-compliance and did not complete the required questionnaires.
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.
| Characteristic | Unit | Arm 1: Low Dose | Arm 2: High Dose | Total |
|---|---|---|---|---|
| Participants analysed | 1 | 1 | 2 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 1 | 1 | 2 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 1 | 1 | 2 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 1 | 1 | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Pain Control Rate as Measured by the The Brief Pain Inventory, measured over 6 months after completion of treatment.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The stated primary endpoint is pain control rate measured with the Brief Pain Inventory (BPI), at 6 months after completion of treatment. The registry describes the BPI as a 17 item patient self-rating scale assessing demographic data, use of medications, and sensory and reactive components of pain. This captures a patient-reported perspective rather than relying only on a clinician’s description of symptoms.
A pain-control endpoint can be useful in a study of radiation dose because it focuses on a patient-relevant outcome. But the registry record does not define how the BPI responses were to be translated into a rate. It does not specify a threshold for classifying a participant as having pain control, a baseline-to-follow-up change rule, or how medication use or incomplete item responses would affect classification. Without those definitions, the title alone is not enough to reconstruct the endpoint.
Most importantly, the record says that neither participant completed the required questionnaires. One participant experienced disease progression and could not continue; the other was removed due to non-compliance. Thus, the planned BPI-based primary outcome is not available as a completed comparison in the posted results. The assessment time remains part of the planned endpoint, but no observed pain-control rate at that time is reported.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes that the study was intended to compare two single-fraction stereotactic radiosurgery dose levels for localized spine metastases. It does not establish which dose had better pain control. Although the primary outcome is named and its planned assessment time is specified, neither participant completed the required questionnaires, and no primary analysis is reported. There is therefore no observed arm-level pain-control result in the record from which to estimate a treatment contrast or its precision.
This is not a case where a reported estimate is simply uncertain. The primary endpoint data needed for that estimate are absent. A confidence interval, when available, describes the range of effect values reasonably compatible with the data under the analysis; its width conveys precision. Here, the registry does not report a primary effect estimate or confidence interval to interpret. No p-value for the primary comparison is reported either. It would be inappropriate to infer a null effect, equivalence, or a difference from the absence of those results.
The record notes a disease progression that prevented one participant from continuing questionnaires and removal of the other participant due to non-compliance. These are different stated reasons for missing primary-outcome data. They do not reveal what the participants’ pain-control scores would have been, and they do not establish how missingness relates to the underlying outcome. With the planned outcome unobserved for both, an analysis based on completed questionnaires cannot provide a comparative estimate. The registry record does not report an alternative analysis intended to address the missing endpoint.
The safety entries are also limited. The low-dose arm lists 1 participant at risk for serious adverse events and 1 affected; the high-dose arm lists 1 at risk and 0 affected. For other adverse events, each arm lists 1 at risk and 1 affected. The listed serious-event terms are each marked 100.0%, but the record does not provide enough context to interpret those percentages as comparative risks for particular terms. Deaths are not reported in the registry record. These entries should be read as registry-reported counts, not as a stable estimate of safety differences between dose levels.
The study is marked terminated, but the reason is not reported in the registry record. The status and the absence of completed primary questionnaires explain why the intended efficacy question remains unanswered in the posted information; they do not show that either dose was ineffective or effective. Any planning illustration based on an observed effect would also require a usable observed effect and a specified comparison. The primary outcome is explicitly not reduced to one comparison, and no primary analysis is listed, so no planning illustration can substitute for the missing clinical result.
9. Statistical Methods Explained
What does randomization contribute?
In general, randomization assigns participants to study groups using a chance-based process. When properly implemented, it can reduce systematic differences between groups at the start of a trial and support a fair comparison. The registry labels this study randomized and its model parallel. Its brief summary describes assignment as like flipping a coin. The specific sequence-generation and allocation-concealment procedures are not reported in the registry record, so the record does not allow those implementation details to be assessed.
Randomization does not guarantee that groups will be similar in every respect, especially in a very small study. It also cannot correct missing outcome measurements that arise after assignment. Here, the primary endpoint was not completed by either participant, so random allocation does not yield an observed BPI-based comparison.
What does the endpoint measure?
The BPI is described as a 17 item patient self-rating scale covering demographic data, medication use, and sensory and reactive components of pain. Patient self-report can capture aspects of pain that may not be fully represented by clinical observations alone. The planned primary outcome is called a pain control rate, assessed 6 months after treatment completion.
For statistical interpretation, the operational definition matters: a rate requires a clear rule for classifying the outcome, and that rule is not reported in the registry record. The record also does not specify a score threshold, a change-from-baseline criterion, or a method for combining the BPI components. Consequently, the named endpoint cannot be independently reconstructed from the description. No completed questionnaire results or primary analysis are reported.
Why does missing outcome information matter?
In general, missing data reduce the information available for estimating an outcome. The implications depend in part on why measurements are missing and how the reasons relate to the unobserved values. A person who cannot continue after disease progression may differ in important ways from a person whose questionnaire is missing for another reason. The registry gives progression as the reason for one participant’s incomplete questionnaires and non-compliance as the reason for the other’s, but it does not describe a statistical method for handling either situation.
Methods such as imputation or sensitivity analysis can be considered in some studies, but their appropriateness depends on the endpoint, the pattern and reasons for missingness, and explicit assumptions. The record does not report such methods or their assumptions. It would be unjustified to fill in outcomes or to treat incomplete questionnaires as evidence of either pain control or lack of control.
How should estimates and uncertainty be understood?
In general, an effect estimate describes the observed contrast between groups, while a confidence interval communicates uncertainty around that estimate. A p-value addresses compatibility between the observed data and a specified null model; it does not measure the size or clinical importance of an effect. These tools require outcome data and a defined comparison. The registry record reports no primary estimate, confidence interval, or primary p-value, and therefore supports no numerical inference about the difference in pain control between the dose groups.
The record states that there are four outcome measures and lists Local Control Rate as a secondary outcome, but it does not provide a completed primary analysis. The primary outcome is described as having several categories or time points and is not reduced to one comparison. A statistical analysis needs a clear outcome definition, time point, contrast, and analysis population; without those elements, a single test or effect summary cannot be inferred from the endpoint title.
What do the planning assumptions mean?
In general, a sample-size calculation estimates how many participants a future study might need under stated assumptions about an effect, variability, significance level, allocation, and analysis. A calculation based on an observed effect is a planning illustration, not an observed power result and not evidence that the original study had adequate power. The record describes planning assumptions that include a two-sided significance level of 0.05, equal allocation, a normal approximation, and target effects expressed as fractions of an observed effect. It distinguishes participant-per-arm illustrations from total-event calculations for time-to-event outcomes.
Those assumptions do not provide a valid substitute for the missing primary outcome. The record does not report a primary effect that can support the intended pain-control comparison, and it says the primary outcome is not reduced to one comparison. The sample-size assumptions are therefore not evidence of the trial’s own design justification. A sample-size justification and any interim analyses are not reported in the registry record.
Why can over-dispersion matter?
In general, a statistical model may assume a particular amount of variation in its outcome. Over-dispersion occurs when observed variation is greater than the model assumes. If it is ignored, standard errors can be too small and confidence intervals too narrow, which may make evidence appear more precise than it is. Whether over-dispersion is relevant depends on the outcome type and model. The registry does not report a primary analysis model or enough outcome data to assess this issue for the planned pain-control rate.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity arises when a study evaluates more than one outcome, time point, group contrast, or statistical test. In general, testing several questions can increase the chance that at least one result appears notable by chance. A statistical plan may address this through a hierarchy of outcomes, adjusted testing, or a prespecified focus on a primary comparison. The registry lists a primary outcome, Local Control Rate as a secondary outcome, and four outcome measures. It does not report a multiplicity strategy or a full analysis plan.
The primary endpoint is described as having several categories or time points and is not reduced to one comparison. The exact set of planned comparisons, how the primary outcome would be summarized, and how secondary outcomes would be interpreted are not reported in the registry record. No primary analyses are listed. As a result, there is no reported family of tests or hierarchy to evaluate, and no primary p-value or confidence interval to interpret.
Missing data are central to this record. One participant experienced disease progression and could not continue the required questionnaires; the second was removed due to non-compliance and did not complete them. The record does not report an analysis population, a rule for questionnaire completion, or a missing-data method. It also does not report an intention-to-treat analysis or a per-protocol analysis. These omissions matter because excluding participants, imputing values, or using only completed questionnaires can lead to different interpretations, and the record does not indicate which approach was intended.
Neither an adjustment for multiple comparisons nor a method for handling incomplete questionnaires should be assumed from the randomized design. The registry record does not report interim analyses or stopping boundaries. The terminated status is recorded, but a reason for termination is not reported in the registry record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Arm 1: Low Dose | 1 | 1 | 100.0% |
| Arm 2: High Dose | 0 | 1 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Arm 1: Low Dose | 1 of 1 |
| Arm 2: High Dose | 1 of 1 |
Most frequent serious adverse event terms
| Event term | Organ system | Arm 1: Low Dose | Arm 2: High Dose |
|---|---|---|---|
| Back pain | Musculoskeletal and connective tissue disorders | 1 of 1 | 0 of 1 |
| Neck pain | Musculoskeletal and connective tissue disorders | 1 of 1 | 0 of 1 |
| Vomiting | Gastrointestinal disorders | 1 of 1 | 0 of 1 |
| Diarrhea | Gastrointestinal disorders | 1 of 1 | 0 of 1 |
| Hypertension | Vascular disorders | 1 of 1 | 0 of 1 |
| Abdominal pain | Gastrointestinal disorders | 1 of 1 | 0 of 1 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Arm 1: Low Dose | Arm 2: High Dose |
|---|---|---|---|
| Alkaline phosphatase | Investigations | 1 of 1 | 1 of 1 |
| Hypertension | Vascular disorders | 0 of 1 | 1 of 1 |
| Vomiting | Gastrointestinal disorders | 0 of 1 | 1 of 1 |
| Abdominal pain | Gastrointestinal disorders | 0 of 1 | 1 of 1 |
| Back pain | Musculoskeletal and connective tissue disorders | 0 of 1 | 1 of 1 |
Serious events with the highest arm-level rate: back pain (100.0%), neck pain (100.0%), vomiting (100.0%), diarrhea (100.0%), hypertension (100.0%).
The registry lists serious adverse events by arm. In the low-dose arm, 1 participant is listed as at risk and 1 as affected. In the high-dose arm, 1 participant is listed as at risk and 0 as affected. For other adverse events, each arm lists 1 at risk and 1 affected. Deaths are not reported in the registry record.
The record lists Back pain, Neck pain, Vomiting, Diarrhea, Hypertension, and Abdominal pain among the top serious-event terms, each marked 100.0%. It does not explain the denominator or provide enough term-specific detail to establish how these percentages relate to the arm-level counts. They should not be read as comparative rates between dose groups or as evidence of a general risk level.
These safety entries are sparse, and the record does not report enough detail about event timing, severity grading, attribution, or term-by-arm distribution to support a robust comparison. The counts describe what is entered in the registry; they do not establish that the observed difference in serious-event counts reflects a dose effect. The posted safety information should be interpreted alongside the absence of a completed primary outcome, rather than as a replacement for that outcome.
12. What the Result Does, and Does Not, Mean
The record shows an intended randomized comparison of single-fraction stereotactic radiosurgery at 14 Gy and 18 Gy for one or two localized spine metastases. It identifies pain control measured by the BPI at 6 months after completion of treatment as the primary outcome. It also reports that the required questionnaires were not completed by either participant: one could not continue after disease progression, and the other was removed due to non-compliance.
As a result, the posted information does not provide a completed primary endpoint comparison. It does not support a conclusion that one dose produced more pain control, that the doses were equivalent, or that either dose lacked an effect. An absence of a reported estimate is not an estimate of no difference. The record also does not provide a primary confidence interval or p-value that could quantify uncertainty around a contrast.
The limited adverse-event counts are descriptive registry entries, not a dependable comparative safety estimate. The listed counts and serious-event terms do not provide enough detail to establish differences between arms, and deaths are not reported in the registry record. Likewise, the terminated status does not disclose why the study ended; no reason is reported.
What the record can establish is the intended question, the dose levels, the planned BPI endpoint and timing, and the stated reasons that questionnaires were not completed. It cannot establish the treatment effect on pain control from the posted primary outcome information. Any interpretation of the trial should keep that distinction clear: the design describes a comparison that was planned, while the reported primary-outcome data do not resolve it.
13. Why This Trial Matters Statistically
This study illustrates why a clear endpoint definition and completed outcome collection are essential to a randomized comparison. The BPI is identified as the instrument, and the planned assessment time is specified, but the record does not state how responses would be classified as a pain-control rate. Even with an identified instrument and time point, a result is difficult to interpret unless the endpoint rule and analysis are clear.
The record also shows that randomization alone cannot ensure an answer to the research question. Random allocation can support comparability at the start of a study, but it does not create information about an outcome that was not measured. Here, the record gives distinct reasons for the missing questionnaires—disease progression for one participant and non-compliance for the other—without reporting a method to address the missing outcomes.
Finally, the study underscores the difference between a planned design and an analyzable result. The record identifies two dose levels and a primary question, but lists no primary analyses and no completed questionnaire results. The terminated status is known, while its reason is not reported. For readers assessing clinical trial evidence, this means that design details, outcome availability, and analysis reporting must be considered separately. A randomized label is important, but it is not a substitute for an observed endpoint, a defined comparison, and an interpretable estimate with its uncertainty.
14. 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 most consequential limitation in the registry record is the absence of completed primary-outcome questionnaires. Both participants failed to complete the required questionnaires, for different stated reasons. With no reported BPI-based outcome values, the planned pain-control comparison cannot be estimated from the posted results.
The endpoint description also leaves important operational details unspecified. Although the record names a pain-control rate and describes the BPI, it does not report the rule for classifying pain control, how the scale components would be combined, or how incomplete item responses would be treated. It does not report a baseline comparison or the method for handling missing follow-up information.
Other analysis details are also absent: the randomization procedure, allocation concealment, a statistical analysis plan, a primary comparison, an analysis population, multiplicity handling, and interim analyses are not reported in the registry record. The study is marked terminated, but the reason for termination is not reported. The listed adverse-event data are limited, with little term-specific or timing information, and deaths are not reported in the registry record. These limitations restrict interpretation of both efficacy and safety; they do not demonstrate a particular treatment effect or lack of effect.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Stereotactic Radiosurgery (SRS) for Spine Metastases — NCT00593320.
- Registry record last updated 2015-03-04; status last verified 2015-02.
- Results first posted 2015-03-04.
- 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.
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18. Record Summary
The registry record describes a randomized, unmasked, parallel study sponsored by Washington University School of Medicine. It concerns stereotactic radiosurgery for one or two localized spine metastases, comparing single-fraction treatment at 14 Gy in the low-dose arm with 18 Gy in the high-dose arm. Enrollment is listed as 2; the study status is terminated. The listed start is 2007-09 and the primary completion date is 2010-03.
The primary outcome is pain control rate measured by the BPI at 6 months after treatment completion. The record says neither participant completed the required questionnaires, citing disease progression for one and non-compliance for the other. No primary analysis is listed. Local Control Rate is listed as a secondary outcome. The reason for termination, detailed analysis plan, and deaths are not reported in the registry record.