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 Body Radiation Therapy and Vertebroplasty in Treating Patients With Localized Spinal Metastasis (NCT00855803), a na phase 2 study. The primary outcome is Pain Response as Measured by VAS at 3 Months.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00855803 |
| Phase | Phase 2 |
| Condition | Metastatic Cancer, Pain, Unspecified Adult Solid Tumor, Protocol Specific |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 35 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Texas Southwestern Medical Center |
| Results posted | Yes |
2. Clinical Question
Population
Adults with localized spinal metastasis were the intended study population. The registry description states that participants were required to have a pain score of at least 4 associated with spine metastases at baseline. The primary endpoint was defined for patients evaluable at the 3 month timepoint; the number evaluable for that endpoint is not reported in the registry record.
Intervention
The registered treatment sequence was radiation followed by vertebroplasty. The study description identifies stereotactic body radiation therapy as the radiation approach. It distinguishes treatment according to whether a participant had prior radiotherapy, but the available description does not give a complete schedule for every participant.
Comparator
There was no separate comparator group. The record identifies a single-group study, with no allocation to a control arm. The intervention is therefore not evaluated against a concurrent untreated group or another treatment group in this trial.
Primary question
The primary question was whether a pain response, measured by the Visual Analogue Scoring System, was recorded at 3 months among evaluable participants. The registry defines complete response as a pain score of 0 and partial response as a decrease of at least 2 points. It does not report the numbers with complete response, partial response, or no response in the information available for this analysis.
3. Trial Design
This is a phase II study of stereotactic body radiation therapy and vertebroplasty for localized spinal metastasis. The registry identifies the design as single-group, with allocation listed as not applicable and masking listed as none. The study is marked completed. Registered enrollment is 35.
The intervention was described as radiation followed by vertebroplasty. The registry record says that all patients would undergo this sequence. It also describes different stereotactic body radiation therapy schedules according to prior radiotherapy: patients with prior radiotherapy would undergo 5 fractions, while the description for patients without prior radiotherapy is truncated. Further details of that schedule are not reported in the registry record.
The study began in 2009-02, and primary completion is recorded as 2021-01-20. These dates describe the registered study timeline; they do not indicate when any individual participant received treatment or completed follow-up.
Secondary outcomes listed in the registry include pain response, overall survival, daily function, and quality-of-life questionnaire responses. The primary outcome was pain response at 3 months. A single-group design can describe outcomes among participants receiving the treatment sequence, but without a concurrent comparator it cannot establish how those outcomes would differ under another treatment or no treatment. The registry record does not report a statistical analysis plan or a comparative treatment estimate.
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 | Total Population |
|---|---|
| STARTED | 35 |
| COMPLETED | 21 |
| NOT COMPLETED | 14 |
Reasons for not completing this period:
| Reason | Total Population |
|---|---|
| Death | 2 |
| Lost to Follow-up | 2 |
| Technical inability to undergo procedure | 2 |
| Not evaluable at 3 month timepoint | 2 |
| Withdrawal by Subject | 3 |
| Physician Decision | 3 |
Analysis population for the primary outcome, as defined in the registry: Patients who were evaluable at the 3-month timepoint
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.
Population: 35 patients enrolled to the study, 29 patients started protocol treatment and had study specific measures completed.
| Characteristic | Unit | Total Population |
|---|---|---|
| Participants analysed | 35 | |
| Age, Continuous | years | 60 (40 to 77) |
| Sex: Female, Male: Female | Participants | 16 |
| Sex: Female, Male: Male | Participants | 19 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 7 |
| Race (NIH/OMB): White | Participants | 27 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Primary Site: Lung | participants | 10 |
| Primary Site: Breast | participants | 4 |
| Primary Site: Prostate | participants | 4 |
| Primary Site: Kidney | participants | 4 |
| Primary Site: Melanoma | participants | 3 |
| Primary Site: Colorectal | participants | 2 |
| Primary Site: Oropharyngeal | participants | 1 |
| Primary Site: Thyroid | participants | 1 |
| Spine Location: Cervical | participants | 4 |
| Spine Location: Thoracic | participants | 12 |
| Spine Location: Lumbar | participants | 13 |
| Number of vertebrae treated: 1 | participants | 23 |
| Number of vertebrae treated: 2 | participants | 6 |
| Preexisting endplate fracture: Yes | participants | 5 |
| Preexisting endplate fracture: No | participants | 24 |
6. Primary Endpoint
The registry lists the primary outcome as Pain Response as Measured by VAS at 3 Months, measured over 3 month.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is pain response measured by the Visual Analogue Scoring System at 3 months. The registry describes a pain scale from 0, meaning no pain, to 10, meaning the most severe pain. Participants were required to have baseline pain of at least 4 associated with spinal metastases.
The record distinguishes complete response, partial response, and no response. A score of 0 is defined as a complete response. A decrease in score of at least 2 points is defined as a partial response. The stated endpoint description says that follow-up scores were used to determine the numbers in these response categories, among participants evaluable at the 3-month timepoint.
Using a defined patient-reported scale makes the endpoint interpretable in terms of change in reported pain, rather than relying only on a general impression of improvement. Categorizing responses also gives a clear way to describe complete and partial responses separately. However, categorization can conceal variation within categories: participants who meet the same response definition may have different starting scores or different changes. The registry record does not report the observed category counts or a summary of change in the scale. It therefore supports explanation of the endpoint definition, but not a conclusion about the frequency or size of pain responses.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies pain response at 3 months as the primary endpoint, but the endpoint results are not reported in the registry record. In particular, the numbers of evaluable participants with complete response, partial response, and no response are not reported in the registry record. Without those outcome counts, the frequency of response and the precision of any response estimate cannot be assessed from the recorded information.
The registered enrollment is 35, while the primary endpoint population is described as patients evaluable at the 3-month timepoint. These are not interchangeable quantities: enrollment describes entry into the study, while an evaluable endpoint population refers to participants with information suitable for assessing that outcome. The number evaluable for the primary endpoint is not reported in the registry record. The safety figures also use a group with 29 at risk, but that denominator should not be substituted for an endpoint denominator.
The design is single-group. Consequently, even if a response proportion were available, it would describe outcomes in this treated group rather than a randomized contrast. Changes over time could reflect treatment, the natural course of illness, other care, measurement variability, or selective availability of follow-up data. The record does not provide a control-group estimate that would help separate these possibilities.
The endpoint has explicit clinical-scale definitions, which aid consistent classification. Yet the registry record does not supply the distribution of baseline scores, changes in scores, or response counts. It is therefore not possible to evaluate how many participants met either response definition, how much scores changed overall, or how precise those estimates would be.
Registration details also list secondary outcomes, including overall survival, daily function, and quality-of-life questionnaire responses. Their presence in a list of outcomes does not establish that results for them are available. Results for those outcomes are not reported in the registry record. The appropriate reading is therefore limited: the record specifies what was intended to be measured, and includes a small set of safety counts, but it does not provide the primary pain-response result needed to quantify the endpoint.
9. Statistical Methods Explained
A clinical endpoint is the outcome used to address a study question. Here, the primary endpoint is a categorized pain response at 3 months. The registry defines a complete response as a pain score of 0 and a partial response as a score decrease of at least 2 points. These definitions determine how an individual’s follow-up measurement is classified. They do not, on their own, say how many participants had each outcome or how uncertain a group-level estimate would be.
What does a response count describe?
For a binary outcome, the basic group summary is the number of participants meeting the event definition, interpreted in relation to the number assessed. In this trial, the endpoint description includes three categories: complete response, partial response, and no response. Those categories could be presented separately, or a prespecified analysis could combine categories, but the registry record does not report an analysis choice or response counts. No combined response result should be inferred from the definitions alone.
A confidence interval is a statistical way to express uncertainty around an estimate. In general, it describes a range of values that are reasonably compatible with the observed data under the assumptions of the method. A wider interval indicates less precision than a narrower interval. An interval cannot be reconstructed responsibly without the relevant outcome data and analysis details. The registry record does not report a confidence interval for the primary endpoint.
Why does the design matter?
In a single-group study, an outcome summary describes participants who received the registered intervention sequence. A comparison between groups is not available within the study. A one-group estimate may be useful for describing what was observed, but it cannot by itself establish the effect attributable to treatment. A causal comparison generally needs a suitable counterfactual, often supported by random assignment and a concurrent comparator. This record identifies no randomized comparison and no comparator arm.
Masking is listed as none. In general, masking can reduce the influence of expectations on measurement or assessment, depending on the outcome and who is masked. Patient-reported pain can be affected by reporting and context, so an unmasked design is relevant when interpreting such an endpoint. The record does not describe additional steps used to reduce measurement or assessment bias.
What do the planning assumptions mean?
The registry information describes sample-size illustrations based on an observed effect. These are planning illustrations, not observed power and not evidence that the study was designed using that effect. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a fraction of the observed effect. For time-to-event outcomes, the stated convention is to show the total number of events using the Schoenfeld approach; other outcomes are expressed as participants per arm.
Those assumptions do not describe the actual study design, which is single-group. Nor do they establish that a two-arm comparison occurred. The observed effect needed to interpret such planning illustrations is not reported in the registry record, and no illustration values are included in the registry entries. A planning calculation asks what sample size might be needed under specified assumptions; it does not measure the probability that a completed study found a real effect.
Why might variability matter?
General statistical methods often account for over-dispersion when outcome variability exceeds what a simpler model assumes. Over-dispersion can make standard errors too small if it is ignored, producing confidence intervals that are too narrow and tests that appear more decisive than warranted. This is a general consideration, not a method reported for this study. The registry record does not report a statistical model or whether over-dispersion was assessed.
For a repeated pain measure, general analytic options could include comparing change from baseline or modeling measurements over time. Such approaches require decisions about which measurements to include, how to handle incomplete follow-up, and what summary answers the clinical question. The registry identifies the endpoint timepoint and response definitions but does not report those analytic details. No particular model, adjustment, or uncertainty calculation should therefore be attributed to the investigators on the basis of this record.
Finally, statistical significance and clinical meaning are different concepts. A significance test, when used, evaluates data relative to a specified null hypothesis and assumptions. An effect estimate and its uncertainty convey magnitude and precision. Neither can be interpreted for the primary endpoint because its results are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists several secondary outcomes in addition to the primary pain-response endpoint. When a study evaluates multiple outcomes or multiple analyses, the chance of a false-positive finding can increase if each is tested independently without an appropriate plan. General approaches include identifying a primary outcome in advance, adjusting inference across tests, or treating secondary analyses as exploratory. The registry record identifies a primary outcome, but does not report a multiplicity strategy or a statistical analysis plan.
The record lists 5 outcome measures and 0 analyses. This indicates that analysis entries are not reported in the registry record; it does not establish whether analyses were conducted outside the registry or whether any results were omitted. Results for the listed secondary outcomes are not reported in the registry record.
Missing data are especially relevant when the primary endpoint is defined among participants evaluable at a follow-up timepoint. If endpoint availability is related to health status, treatment experience, or other outcome-related factors, an analysis restricted to observed measurements can differ from the experience of all enrolled participants. General methods may use explicit assumptions or sensitivity analyses to examine such uncertainty. The registry record does not report how missing endpoint data were handled, how many participants lacked an evaluable measurement, or whether sensitivity analyses were performed.
Analysis populations also matter. An analysis might include everyone enrolled, those who began treatment, or only participants meeting endpoint-specific evaluability criteria. These populations answer different questions. The primary endpoint description specifies an evaluable population, but the criteria beyond that wording and the number included are not reported in the registry record. The registered enrollment should not be treated as the endpoint denominator.
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 |
|---|---|---|---|
| Total Population | 1 | 29 | 3.4% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Total Population | 2 of 29 |
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 |
|---|---|
| Total Population | 3 of 29 |
Most frequent serious adverse event terms
| Event term | Organ system | Total Population |
|---|---|---|
| Acute myelopathy | Nervous system disorders | 1 of 29 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Total Population |
|---|---|---|
| Esophagitis | Gastrointestinal disorders | 1 of 29 |
| Acute hematoma | Injury, poisoning and procedural complications | 1 of 29 |
| Urinary retention | Renal and urinary disorders | 1 of 29 |
| Metastatic renal cell carcinoma | Renal and urinary disorders | 1 of 29 |
| Spinal canal stenosis | Nervous system disorders | 1 of 29 |
| Laminectomy | Surgical and medical procedures | 1 of 29 |
Serious events with the highest arm-level rate: acute myelopathy (3.4%).
The safety information identifies a Total Population group with 29 at risk for the serious-event and other-event summaries. It records 1 participant with a serious adverse event, 3 participants with another adverse event, and 2 deaths. These are separate reported counts; the registry record does not state that the categories are mutually exclusive, so they should not be added together or treated as separate sets of people.
Acute myelopathy is listed as the top serious term at 3.4%. This percentage is reported as written. The registry information does not specify further context for the term, such as timing, attribution, severity grading, or whether it was considered related to treatment. The term and percentage therefore describe what is listed, not a causal conclusion.
Counts of participants with events are not a complete description of safety. Interpretation may depend on the event definitions, duration of observation, completeness of reporting, and whether events were judged related to treatment. Those details are not reported in the registry record. The safety figures should be read as recorded counts and a listed term, not as a comparison with another treatment or as an estimate of comparative risk.
12. What the Result Does, and Does Not, Mean
The registry record describes a phase II, single-group study in which the registered treatment sequence was radiation followed by vertebroplasty. It defines a primary pain-response endpoint at 3 months, including criteria for complete and partial response. This makes the intended outcome and its classification understandable.
However, the primary endpoint result is not reported in the registry record. There are no recorded counts for complete response, partial response, or no response, and the number evaluable at the endpoint is also not reported. Thus, the record does not support a numerical estimate of pain response or its precision. The safety information gives counts and a listed serious-event term, but does not supply the context needed to make a treatment comparison.
Even a complete outcome summary from a single-group study would not, by itself, show what would have happened to comparable participants under another treatment or without the intervention. Without a concurrent comparator, observed changes can have multiple explanations. A single-group result can describe outcomes in the study population, but cannot isolate a treatment effect with the strength of a randomized comparison.
The study’s listed secondary outcomes broaden the intended areas of assessment, including survival, daily function, and quality of life. Their inclusion in the registry is not evidence of a favorable or unfavorable result. Those results are not reported in the registry record. In sum, the record supports describing the study design, treatment sequence, endpoint definitions, and limited safety counts. It does not support a conclusion about the amount of pain response, comparative benefit, or causal effects.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of why endpoint definitions and outcome results must be read separately. The registry gives a clear pain scale and categorical response rules, but the response counts and endpoint denominator are not reported in the registry record. Without them, the central outcome cannot be quantified. A well-defined endpoint is necessary for analysis, but it is not a substitute for reporting the observed data.
The single-group design also illustrates the distinction between describing outcomes and estimating a comparative effect. A group’s follow-up experience can be summarized, but attribution requires a credible comparison that addresses what might have occurred otherwise. The registry identifies no comparator group, so the design places a limit on causal interpretation regardless of how clearly the endpoint is defined.
The information also highlights the importance of analysis-population reporting. Registered enrollment is 35, while the primary outcome is described for participants evaluable at follow-up. Reporting the endpoint denominator, missingness, and handling of incomplete measurements would be necessary to judge how representative the analyzed group is of those enrolled.
Finally, registry-listed planning assumptions should not be confused with trial results or with proof of adequate power. The described sample-size illustrations use assumptions that do not match the single-group design as a direct treatment comparison. Clear distinction among design, planned calculations, observed outcomes, and uncertainty is essential for a statistically responsible reading.
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 primary limitation for interpretation is that the primary pain-response result is not reported in the registry record. The record also does not report the number evaluable at the 3-month endpoint, the distribution of baseline pain scores, or the amount of change in scores. These omissions prevent assessment of both the response frequency and its precision.
The single-group design has no concurrent comparator, and allocation is listed as not applicable. Any observed outcomes would therefore be descriptive of the study group rather than a direct randomized estimate against another care strategy. Masking is listed as none, which is relevant when considering a patient-reported outcome. The record does not describe other measures to address reporting or assessment influences.
The available treatment description is incomplete for the schedule among participants without prior radiotherapy. Additional treatment details, including whether there were variations in care, are not reported in the registry record. The registry also does not report the statistical analysis plan, handling of missing endpoint measurements, or methods for addressing multiple outcomes.
The listed adverse-event counts have limited interpretive context. The record does not report attribution, observation duration, event grading, or whether event categories overlap. Those figures should not be read as comparative safety estimates. Finally, the secondary outcomes are named, but their results are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Stereotactic Body Radiation Therapy and Vertebroplasty in Treating Patients With Localized Spinal Metastasis — NCT00855803.
- Registry record last updated 2022-03-16; status last verified 2022-02.
- Results first posted 2022-03-16.
- 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 identifies NCT00855803 as a completed phase II, single-group study of stereotactic body radiation therapy followed by vertebroplasty for localized spinal metastasis. Enrollment is 35, masking is listed as none, and the primary endpoint is pain response measured by VAS at 3 months.
The endpoint definitions classify a score of 0 as complete response and a decrease of at least 2 points as partial response. The primary outcome counts and endpoint denominator are not reported in the registry record. Safety information lists 1 participant with a serious adverse event, 3 with another adverse event, and 2 deaths among a group of 29 at risk; acute myelopathy is listed at 3.4%. These figures have no concurrent comparator and limited reporting context.