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 Anderson Circulating Tumor Cell Burden (CTCB) Study (NCT00819832), a randomized phase 4 study. The primary outcome is Phase 1: Time to Maximal Circulating Tumor Cell Burden (CTCB).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00819832 |
| Phase | Phase 4 |
| Condition | Cancer, Spinal Disease, Vertebral Compression Fractures |
| Allocation | Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | M.D. Anderson Cancer Center |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned people with painful vertebral compression fractures secondary to malignancy. The registry record describes the intended population in those terms; it does not report participant-level characteristics or eligibility details. Enrollment is recorded as 3, but the record does not establish how many participants contributed usable measurements or completed follow-up.
Intervention
The planned procedures were vertebroplasty and kyphoplasty. In Phase 2, each procedure was also to be assessed with the Cavity SpineWand, a device used with the procedure. The stated primary focus was circulating tumor cell burden (CTCB) measured in peripheral blood after treatment.
Comparator
The Phase 2 plan described procedure groups with and without the Cavity SpineWand. Phase 1 instead sought to identify when CTCB reached its maximum after standard vertebroplasty or kyphoplasty, relative to baseline. The record does not report completed group comparisons or the results of any such comparison.
Primary question
The Phase 1 primary question was when maximal CTCB occurred after the procedures compared with baseline. The Phase 2 primary question was how CTCB changed from baseline to after treatment and whether average change differed between treatment groups. The registry record states that the sponsor terminated the study and no data analysis was done on the limited data gathered, so these questions have no reported statistical answer.
3. Trial Design
The registry identifies the study as Phase 4, with randomized allocation and no masking. It also lists the model as single group. Those design descriptors do not form a straightforward account of the planned comparisons: the study summary describes a Phase 1 optimization phase and a Phase 2 comparison phase, with procedure groups both with and without the Cavity SpineWand. The record does not clarify how the randomized allocation field relates to the single-group model or to the planned phases.
In Phase 1, the stated objective was to determine when maximal CTCB occurred after standard vertebroplasty or kyphoplasty, relative to baseline. In Phase 2, the objective was to compare average change in CTCB between groups with and without the Cavity SpineWand. Additional planned measures concerned self-reported spine pain, pain status, symptoms, and time to walk a 50-foot distance.
The interventions listed are kyphoplasty, vertebroplasty, and the Cavity SpineWand. The arm descriptions include vertebroplasty and kyphoplasty groups in both phases, as well as groups combining each procedure with the device in Phase 2. The record does not report which planned groups were actually enrolled or treated.
Enrollment is recorded as 3. The study start is listed as 2008-12 and primary completion as 2010-05. Its status is terminated, and the registry narrative states that no data analysis was done on the limited amount of data gathered. The reason for termination, implementation details, and any departure from the described design 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.
Before assignment: Study terminated by sponsor. No patient data analysis performed due to the limited amount of data gathered from the study's three participants.
Overall Study
| Stage | Phase 1 Group 1 Vertebroplasty | Phase 1 Group 2 Kyphoplasty | Phase 2 Group 1 Vertebroplasty | Phase 2 Group 2 Vertebroplasty +Cavity SpineWand | Phase 2 Group 3 Kyphoplasty | Phase 2 Group 4 Kyphoplasty + Cavity SpineWand |
|---|---|---|---|---|---|---|
| STARTED | 3 | 0 | 0 | 0 | 0 | 0 |
| COMPLETED | 0 | 0 | 0 | 0 | 0 | 0 |
| NOT COMPLETED | 3 | 0 | 0 | 0 | 0 | 0 |
Reasons for not completing this period:
| Reason | Phase 1 Group 1 Vertebroplasty | Phase 1 Group 2 Kyphoplasty | Phase 2 Group 1 Vertebroplasty | Phase 2 Group 2 Vertebroplasty +Cavity SpineWand | Phase 2 Group 3 Kyphoplasty | Phase 2 Group 4 Kyphoplasty + Cavity SpineWand |
|---|---|---|---|---|---|---|
| Sponsor Termination of Study | 3 | 0 | 0 | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Study terminated by sponsor; No data analysis done on limited amount of data gathered.
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.
Only the first 6 of 7 groups are shown.
| Characteristic | Unit | Phase 1 Group 1 Vertebroplasty | Phase 1 Group 2 Kyphoplasty | Phase 2 Group 1 Vertebroplasty | Phase 2 Group 2 Vertebroplasty +Cavity SpineWand | Phase 2 Group 3 Kyphoplasty | Phase 2 Group 4 Kyphoplasty + Cavity SpineWand |
|---|---|---|---|---|---|---|---|
| Participants analysed | 3 | 0 | 0 | 0 | 0 | 0 | |
| Age, Continuous | years | 63 (49 to 75) | — | — | — | — | — |
| Sex: Female, Male: Female | Participants | 3 | — | — | — | — | — |
| Sex: Female, Male: Male | Participants | 0 | — | — | — | — | — |
| Region of Enrollment: United States | participants | 3 | — | — | — | — | — |
6. Primary Endpoint
The registry lists the primary outcome as Phase 1: Time to Maximal Circulating Tumor Cell Burden (CTCB), measured over Pre-procedure baseline blood draws through post surgery 24 hours followed at 7 days (+/- 2 days).
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The Phase 1 primary endpoint concerns the timing of maximal circulating tumor cell burden after vertebroplasty or kyphoplasty, compared with the pre-procedure baseline. CTCB was to be evaluated from peripheral blood collected at multiple post-surgery times, with follow-up through 7 days. The listed schedule includes draws at 10, 30, and 60 minutes, at 2 hours, at several later intervals on the day of surgery, and at 7 days. The description specifies 10cc per draw and 100 cc collected over the 7 day period.
The purpose of this measurement, as described in the registry, was to identify when the largest post-procedure CTCB occurred relative to baseline. This is a timing question as well as a change-from-baseline question: measurements across follow-up are needed to locate a maximum, rather than relying on a single post-treatment value. The record names the CellSearch™ Assay for the Phase 2 CTCB assessment.
In general, repeated measurements can describe how an outcome changes over time, but interpreting a maximum depends on the measurement schedule and the completeness of observations. The registry record reports no analyzed endpoint values, no estimate of change, and no estimate of the time of maximal CTCB. It also does not report a primary endpoint result for the Phase 2 comparison.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive fact is that the registry record reports no data analysis on the limited amount of data gathered. It therefore provides no statistical estimate of change in CTCB, no estimate of when maximal CTCB occurred, and no comparison of CTCB between groups with and without the Cavity SpineWand. There is no reported effect estimate, uncertainty interval, or test result from which to assess the magnitude or precision of a treatment-group difference.
The enrollment entry is 3, but that figure alone does not describe the amount of usable endpoint information. It does not establish how many participants contributed baseline samples, completed the planned blood-draw schedule, or had evaluable outcome data. Those details are not reported in the registry record. With no analyzed data, no conclusion about the direction or size of CTCB change can be drawn from the entry.
The design information also calls for caution. The record reports randomized allocation, but lists the model as single group, while the study objectives describe planned comparisons between groups. It does not explain how those design fields fit together or identify the actual allocation and analysis procedures used. Consequently, the stated objectives should be read as planned questions, not as evidence that the planned comparisons were completed.
The registry lists additional intended outcomes: spine pain on a visual analogue scale, pain status using the Brief Pain Inventory, symptoms using the M.D. Anderson Cancer Center Symptom Inventory, and time to walk a 50-foot distance. No analysis results for these outcomes are reported. Their inclusion in the objectives does not establish that measurements were collected or analyzed.
In general, a statistical result is most informative when it gives an effect estimate together with uncertainty and a clear description of the population and analysis. None of those outcome-specific results is present in the registry record. The appropriate interpretation is therefore limited to the study plan and its termination, not to whether any procedure or device changed CTCB, pain, symptoms, or walking time.
9. Statistical Methods Explained
The registry describes objectives that would ordinarily require analysis of repeated measurements and, in Phase 2, comparison between treatment groups. It does not report the statistical analysis plan or any completed analysis. The concepts below explain what those methods would address in general; they do not describe analyses confirmed to have been performed in this study.
How would repeated CTCB measurements answer the Phase 1 question?
In general, repeated measurement records the same outcome at multiple times for each participant. Here, the stated aim was to locate the time point at which CTCB was maximal after a procedure relative to baseline. A suitable analysis would need to account for the fact that measurements from the same person are related, rather than treating every blood draw as an independent observation. It would also need to define how a maximum is selected and how the baseline value is used in that comparison.
The schedule matters because a maximum can only be identified among the observed time points. A peak between scheduled draws could be missed. In general, denser measurement at some periods than others can affect how precisely the timing of a peak is characterized. The registry gives a planned schedule but does not report which samples were obtained, how incomplete sampling was handled, or the method that would be used to estimate the maximum.
What would a Phase 2 group comparison estimate?
The Phase 2 objective was to compare average change in CTCB from baseline to post-treatment between groups with and without the Cavity SpineWand. In general, a between-group analysis estimates whether the average outcome change differs across the groups being compared. The interpretation depends on clear definitions of the groups, the measurement times, the analysis population, and the statistical model. The registry describes intended treatment groups but does not report an analysis dataset, group-specific estimates, or a model.
Random allocation can, in general, support a fair comparison by reducing systematic differences between groups at the point of allocation. That benefit depends on how allocation was implemented and on the integrity of follow-up and analysis. The registry reports randomized allocation, but also lists a single-group model and does not clarify how these fields relate to the planned Phase 2 comparisons. It would not be appropriate to infer allocation procedures or a completed randomized comparison from the registry descriptors alone.
What do uncertainty intervals and significance tests mean?
In general, a confidence interval describes a range of effect values that are compatible with the data and the method used to calculate the interval. Its width reflects precision: a wider interval indicates greater uncertainty about the effect size. A significance test evaluates how compatible the observed data are with a specified null hypothesis under its assumptions. A small p-value, by itself, does not show that an effect is large, important, or precisely estimated. This study's registry record contains no outcome estimate, confidence interval, or p-value to interpret.
For repeated outcomes, a model may also need to represent variation between participants and correlation among measurements taken from the same participant. In general, ignoring that correlation can misstate uncertainty. When measurements are sparse or highly variable, estimates of change and timing may be imprecise. The record does not report the variability of CTCB or the distribution of observed measurements, so these features cannot be assessed for this study.
Why can over-dispersion matter?
In general, count outcomes may vary more than a simple statistical model assumes. This is called over-dispersion. If it is present and not accounted for, standard errors and confidence intervals may be too small, making estimates appear more precise than they are. Whether CTCB measurements in this study showed over-dispersion is not reported in the registry record. No model choice or diagnostic assessment is reported.
What can planning calculations say?
In general, sample-size planning calculations estimate how much information a future study might need under stated assumptions about the effect, variability, allocation, and analysis. They are planning illustrations, not observed power and not evidence that a study detected an effect. The registry describes planning assumptions based on a fraction of an observed effect, equal allocation, a two-sided significance level of 0.05, and a normal approximation. It does not report an analyzed observed effect in the outcome record, and the trial itself is described as having no data analysis. The registry does not report the study's own sample-size justification. Any planning figure should therefore be kept separate from evidence about an outcome in this terminated study.
10. Multiplicity, Missing Data and Analysis Populations
The study description includes more than one phase, several planned treatment groups, repeated CTCB time points, and additional outcomes for pain, symptoms, and walking time. In general, testing multiple outcomes, time points, or group contrasts raises a multiplicity issue: the more comparisons considered, the greater the chance that at least one result appears notable by chance. Statistical plans may address this by defining a primary comparison in advance, adjusting tests, or emphasizing estimates and uncertainty rather than isolated tests.
The registry record identifies primary objectives for the two phases, but the statistical plan for handling multiple time points or comparisons is not reported in the registry record. It does not report whether any multiplicity adjustment was planned or used. No outcome analyses or test results are reported, so there is no multiplicity-adjusted or unadjusted result to interpret.
Missing data are also important for the planned repeated blood draws and post-treatment measures. In general, incomplete follow-up can affect estimates if the participants with observed measurements differ systematically from those without them. Appropriate handling depends on what data are missing and why. The record does not report the number or pattern of missing measurements, the reasons for missingness, or a missing-data method.
The analysis population is not reported in the registry record. It is not clear whether any planned analysis would have included all allocated participants, only those treated, or only those with evaluable measurements. Given the stated termination and absence of data analysis, these are unresolved design and reporting questions rather than evidence of a particular analytic choice.
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 |
|---|---|---|---|
| Phase 1 Group 1 Vertebroplasty | 0 | 3 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Phase 1 Group 1 Vertebroplasty | 0 of 3 |
| Phase 1 Group 2 Kyphoplasty | 0 of 0 |
| Phase 2 Group 1 Vertebroplasty | 0 of 0 |
| Phase 2 Group 2 Vertebroplasty +Cavity SpineWand | 0 of 0 |
| Phase 2 Group 3 Kyphoplasty | 0 of 0 |
| Phase 2 Group 4 Kyphoplasty + Cavity SpineWand | 0 of 0 |
The adverse-event entries list 3 participants at risk in the Phase 1 vertebroplasty group, with 0 affected by serious adverse events and 0 affected by other adverse events. The other listed groups each have 0 participants at risk in the adverse-event record and 0 affected entries. These figures describe what the registry record reports; they do not establish that no adverse events occurred during the study.
In particular, a group with 0 participants recorded as at risk does not provide an informative safety rate for that group. The registry does not explain whether those entries reflect no participants enrolled, no participants exposed, or another reporting circumstance. The record also does not supply a usable safety denominator for every planned group.
Deaths are not reported in the registry record. The absence of reported affected entries should not be read as proof that the procedures or device had no safety risks. The study was terminated, enrollment was recorded as 3, and the registry states that only a limited amount of data was gathered. The adverse-event figures are therefore sparse and do not support a comparative safety assessment.
12. What the Result Does, and Does Not, Mean
The record establishes that the study was designed to investigate CTCB after vertebroplasty or kyphoplasty and to compare planned Phase 2 groups with and without the Cavity SpineWand. It also records a Phase 1 objective of identifying when maximal CTCB occurred relative to baseline. These are research questions and planned measurements, not reported findings.
The registry states that the sponsor terminated the study and that no data analysis was done on the limited amount of data gathered. As a result, the record does not show whether CTCB rose or fell, when any maximum occurred, or whether average change differed between groups. It also gives no analyzed result for pain, pain status, symptoms, or walking time. The recorded enrollment of 3 does not supply the missing outcome estimates or establish the completeness of follow-up.
In general, absence of an analysis is not evidence that two approaches are equivalent, nor is it evidence that one is better or worse. Equivalence or difference requires suitable outcome data and an analysis that quantifies the comparison and its uncertainty. Neither is reported. Likewise, the adverse-event entries cannot establish absence of risk because several listed groups have no participants recorded at risk and deaths are not reported.
The appropriate conclusion is narrow: the registry documents a terminated study with planned CTCB and clinical outcome questions, but it provides no analyzed results that answer them. It does not support conclusions about the effect of a procedure or device on CTCB, pain, symptoms, walking time, or safety.
13. Why This Trial Matters Statistically
This study raises a useful statistical distinction between a research question and an answer supported by analyzed data. Its objectives describe both a timing problem—when CTCB reaches a maximum after a procedure—and a comparative problem—whether average change differs between groups. Those questions require observations and analysis suited to repeated measurements and between-group contrasts. The registry records that no analysis was done on the limited data gathered, so the objectives remain unanswered.
The planned repeated blood sampling also illustrates how outcome measurement design shapes interpretation. In general, a time-varying outcome cannot be characterized fully by a baseline and one later value if the main question concerns when a peak occurs. The timing and completeness of measurements matter. The registry describes a schedule, but does not report the measurements obtained or their statistical analysis.
The record also shows why design descriptors need to be read together. It lists randomized allocation and a single-group model, while describing planned groups for comparisons. Because the registry does not reconcile those entries, readers cannot reconstruct the implemented design from the descriptors alone. Precise reporting of allocation, analysis populations, missing measurements, and statistical methods is important for judging what a trial can establish.
Finally, a small recorded enrollment and sparse safety entries limit the amount of information available, but the central issue is not a calculated measure of power: the registry explicitly reports no analysis. Statistical interpretation must therefore stop short of an effect claim. This case underscores the importance of separating intended analyses, observed data, and reported results.
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 registry record leaves important details about study conduct and analysis unresolved. It describes both an optimization phase and a comparison phase, yet lists the model as single group alongside randomized allocation. How the phases were implemented, how participants were assigned, and whether the planned groups were formed are not reported in the registry record.
Enrollment is recorded as 3, but the record does not report participant characteristics, the number who received each procedure, or the number with evaluable endpoint measurements. It does not describe the amount of missing data or whether the planned sampling schedule was completed. These gaps prevent assessment of representativeness, follow-up completeness, and the precision that any analysis might have achieved.
The registry gives a detailed intended schedule for CTCB and names the CellSearch™ Assay for Phase 2, but it does not report assay results, measurement variability, or procedures for handling values below detection or other unusual observations. Such measurement details are not reported in the registry record. The analysis plan, including model choice and handling of repeated measures, is also not reported.
There are no reported outcome estimates for CTCB or the secondary measures, and no reported confidence intervals or test results. The reason the study was terminated is not reported in the registry record. The adverse-event entries provide limited information because most groups have no participants recorded at risk and deaths are not reported. Together, these limitations mean the registry supports description of the intended questions and termination, but not an assessment of treatment effects or comparative safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Anderson Circulating Tumor Cell Burden (CTCB) Study — NCT00819832.
- Registry record last updated 2023-03-24; status last verified 2023-03.
- Results first posted 2010-12-16.
- 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 Anderson Circulating Tumor Cell Burden Study planned to examine circulating tumor cell burden after vertebroplasty or kyphoplasty for painful vertebral compression fractures secondary to malignancy. Its Phase 1 objective concerned the timing of maximal CTCB relative to baseline; Phase 2 was intended to compare change between groups with and without the Cavity SpineWand. Additional planned outcomes concerned pain, symptoms, and walking time.
The registry identifies the study as Phase 4, randomized, unmasked, and single group. Enrollment is recorded as 3; the study status is terminated. The registry states that no data analysis was done on the limited data gathered. It reports no analyzed primary or secondary outcome results, and the statistical plan and study-specific sample-size justification are not reported in the registry record. The entries therefore describe planned questions and limited safety information, not estimates of treatment effects.