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 Image-Guided Navigation for High Dose Rate Temporary Interstitial Brachytherapy in the Palliative Management of Previously Treated Tumors of the Spine and Pelvis (NCT01757717), a na na study. The primary outcome is Maximum Radiation Dose.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01757717 |
| Phase | NA |
| Condition | Metastatic or Recurrent Lesions in the Spine, Metastatic or Recurrent Lesions in the Pelvis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Memorial Sloan Kettering Cancer Center |
| Results posted | Yes |
2. Clinical Question
The study asked whether image-guided surgical navigation could be used to guide placement of radiation catheters for Ir-192 high dose rate (HDR) temporary interstitial brachytherapy in patients with metastatic or recurrent lesions in the spine or pelvis. The registry describes the study as a pilot and frames its purpose around the feasibility of this approach and the radiation dose received by nearby structures.
Population
Patients with painful or symptomatic metastatic or recurrent lesions in the spine and/or pelvis that had been previously treated. The registry lists metastatic or recurrent lesions in the spine and metastatic or recurrent lesions in the pelvis as conditions.
Intervention
Ir-192 high dose rate brachytherapy, with catheter placement using image-guided surgical navigation techniques.
Comparator
There was no separate comparator group. The trial is listed as a single-group study, with allocation recorded as NA.
Primary question
Could the treatment approach be used for spinal and/or pelvic lesions while measuring the maximum radiation dose to the cord or cauda equina? The stated dosimetric aim was a cord/cauda Dmax <8 Gy.
The primary outcome is titled “Maximum Radiation Dose” and is defined as cord/cauda maximum dose in Gy. Its stated timeframe is 1 year. The record describes the goal as verifying feasibility and improving dosimetric coverage of lesions while meeting the stated dose aim for the cord or cauda equina. These are aims, not posted findings: the registry record does not report the observed dose value or whether the stated aim was met.
The clinical question is therefore about feasibility and dose measurement in a small, uncontrolled pilot, rather than a comparison of outcomes between treatments. Without a comparator, the study cannot estimate a relative effect against another treatment approach from its design alone. It can describe experience in the enrolled group, but the posted record does not include the primary outcome result needed to assess that experience.
3. Trial Design
This was a completed pilot study with a single-group model. The registry lists an enrollment of 3 participants and identifies Ir-192 high dose rate (HDR) as the intervention. Allocation is listed as NA and masking as NONE. The phase is listed as NA. Those registry entries do not establish a randomized allocation or a masked comparison; there is no separate control arm in the recorded design.
The listed conditions are metastatic or recurrent lesions in the spine and metastatic or recurrent lesions in the pelvis. The study title and summary place the work in the palliative management of previously treated tumors. The intervention description refers to catheter placement using image-guided surgical navigation, followed by HDR brachytherapy. The registry identifies Memorial Sloan Kettering Cancer Center as the sponsor.
The recorded study start is 2013-01, and primary completion is recorded as 2017-07. Overall status is COMPLETED. These dates and status describe the registry record; they do not by themselves indicate that all outcomes were posted or that the study answered its feasibility question.
A single-group pilot can document whether a procedure and its measurements were undertaken in a small enrolled cohort. It does not provide a concurrent estimate of what would have happened under another approach. In this record, the lack of a comparator is especially important when interpreting any outcomes: observed events or measurements cannot be attributed to navigation or HDR by comparison with an alternative group.
The registry’s arm description is incomplete in the record, ending mid-sentence. It identifies the study as an investigation of Ir-192 HDR afterloader-based brachytherapy with image-guided catheter placement for patients with painful or symptomatic lesions, but further details about eligibility, treatment delivery, and follow-up procedures are not reported in the registry record. A detailed protocol or fuller account of the conduct of the study is not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Ir-192 High Dose Rate (HDR) |
|---|---|
| STARTED | 3 |
| COMPLETED | 3 |
| NOT COMPLETED | 0 |
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 | Ir-192 High Dose Rate (HDR) |
|---|---|---|
| Participants analysed | 3 | |
| Age, Continuous | years | 64 (46 to 76) |
| Sex: Female, Male: Female | Participants | 2 |
| Sex: Female, Male: Male | Participants | 1 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 2 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 1 |
| 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 | 0 |
| Race (NIH/OMB): White | Participants | 1 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 |
| Region of Enrollment: United States | Participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Maximum Radiation Dose, measured over 1 year.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | cord/cauda max dose in Gy |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “Maximum Radiation Dose.” The recorded measure is the cord/cauda maximum dose in Gy, summarized using a median and full range, with a timeframe of 1 year. In general, a dose endpoint describes the amount of radiation received by the specified structure; here, that structure is the spinal cord or cauda equina. This is a dosimetric measure, not a direct measure of pain relief, tumor control, survival, or quality of life.
The endpoint is used because the stated feasibility aim combines treatment of a spinal and/or pelvic lesion with attention to radiation dose in nearby structures. The registry’s description sets a target of cord/cauda Dmax <8 Gy. That target is part of the stated aim; it is not evidence that the observed dose was below the target. The registry record does not report the primary endpoint value, its full range, or whether the target was achieved.
A median gives a measure of the center of a set of observations, while the full range describes the lowest and highest observed values. In general, reporting both can convey the spread of measurements, though a range can be strongly influenced by individual observations. With only 3 participants enrolled, any group summary would need to be read as a description of this small cohort, not as a precise estimate for a broader population. The record does not report how many participants contributed a primary endpoint measurement or how missing measurements, if any, were handled.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive limitation is that the registry record gives the primary outcome definition but not its result. It names maximum radiation dose to the cord or cauda equina, gives the unit as Gy, identifies the summary as a median with a full range, and sets a timeframe of 1 year. It does not report the median, range, number of evaluable participants, or an estimate of precision. As a result, the posted information cannot establish whether the stated dose aim was met.
The stated aim was cord/cauda Dmax <8 Gy while providing dosimetric coverage of lesions. That value is a target in the outcome description, not a reported observation. It should not be read as a trial result. The record also does not report a tumor-coverage result, a measure of catheter-placement accuracy, or a comparison of dose with another technique. The brief summary describes the rationale that navigation may help guide catheter placement and may affect radiation delivery, but it does not report evidence that these possibilities occurred in the enrolled participants.
The study enrolled 3 participants and had no comparator group. Even if outcome values were available, a single-group pilot would provide a descriptive account rather than a randomized comparison. It could not separate the contribution of navigation from other aspects of treatment or patient characteristics. In the current record, the absence of the primary outcome values prevents even a descriptive assessment of the dose distribution.
No statistical analyses are listed in the registry record. There are no reported p-values, confidence intervals, or adjusted estimates for the primary endpoint. A confidence interval, in general, expresses the statistical uncertainty around an estimate; without a reported estimate and interval, the precision of the primary result cannot be assessed. The absence of a reported interval should not be interpreted as evidence of precision or of no uncertainty.
The safety record lists 0 participants with serious adverse events among 3 at risk in the Ir-192 HDR group, 3 participants with other adverse events among 3 at risk, and 2 deaths. Those counts describe the registry categories; they do not identify the causes, timing, severity details for the other events, or relationship to treatment. The registry record does not report whether the deaths were related to the intervention. These safety counts do not substitute for the missing primary dose result.
Overall, the record documents a small completed pilot and its intended dosimetric question. It does not give enough posted outcome information to judge the observed dose, its variability, or the extent to which the feasibility aim was achieved. Conclusions should remain limited to the design and the event counts explicitly recorded.
9. Statistical Methods Explained
The statistical information in the registry is limited. The study is identified as a single-group pilot with enrollment of 3, and no statistical analyses are listed. The primary measure is specified as a median with a full range, but the record does not include the underlying values or a numerical summary. The explanations below describe the statistical ideas relevant to this design in general; they do not imply that the corresponding analyses were performed.
What does the median and full range describe?
In general, the median is the middle value when observations are ordered. It describes the center without being pulled as strongly by an unusually high or low observation as the mean can be. The full range gives the lowest and highest observations and offers a direct, but often unstable, indication of spread. With very few observations, each individual value can substantially affect both the median and the range. A range also does not show how observations are distributed between its endpoints.
For this outcome, the measurement is maximum radiation dose to the cord or cauda equina in Gy. The record specifies a median and full range as the summary, but does not report those values. It also does not report the count of participants with a usable dose measurement. Without the result and denominator, readers cannot assess the observed center, variation, or completeness of this endpoint.
What can a single-group pilot estimate?
In general, a single-group study can describe measurements and events in the people enrolled. Without a comparison group, it does not estimate a treatment contrast. A before-and-after or external comparison would require details and analyses that are not reported in the registry record. In this trial, allocation is listed as NA and the model as SINGLE GROUP, so there is no like-for-like control group in the recorded design.
Small pilot studies are commonly interpreted as preliminary descriptions of feasibility or implementation rather than definitive tests of comparative effects. That general distinction matters because enrollment was 3. A small cohort can make estimates highly sensitive to individual observations, and it limits the information available about variability. The registry does not report an uncertainty interval for the primary measure, so the degree of statistical uncertainty cannot be quantified from the record.
What do significance levels and sample-size illustrations mean?
In general, a significance level is a threshold used in a planned statistical test to control how often a procedure would flag a result under a specified null model. A p-value, when reported, describes how compatible the data are with that model under the test assumptions; it is not the probability that a treatment works or that the null hypothesis is true. No p-value or test result is listed in the registry record.
The registry’s sample-size assumptions describe a planning illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The stated effect to detect is a fraction of the observed effect. Such calculations are planning illustrations, not observed power and not evidence that the trial was designed or conducted as a two-arm comparison. The actual trial is recorded as single-group, and the registry does not report the trial’s own sample-size justification. The observed primary effect needed to interpret effect-based planning is also not reported in the registry record.
In general, a planning calculation estimates the sample size needed under its assumptions. It does not describe the enrolled sample’s achieved power, prove that a result is reliable, or replace an observed treatment-effect estimate. Illustrations based on an observed effect can also be unstable when the underlying study is small, because the observed effect itself may be imprecise. Here, no numerical primary outcome result or inferential analysis is available in the record to support such an interpretation.
Why does dispersion matter?
In general, dispersion describes how far observations vary from one another. For dose measurements, variability can matter alongside the center because a median alone may conceal high or low individual measurements. A full range can reveal extremes, but with a small cohort it does not reliably characterize the wider distribution. The registry specifies a full range, yet does not post one. No inference about over-dispersion can be made from the record. More generally, over-dispersion means that observed variability exceeds what a chosen statistical model expects; this can make standard errors too small and statistical conclusions too confident if not addressed. No count-model analysis or over-dispersion assessment is reported.
What is the role of a confidence interval?
In general, a confidence interval gives a range of values compatible with data and a model under a stated procedure. It helps show precision, which a point estimate alone cannot convey. An interval’s interpretation depends on the study design, measurement process, and assumptions used to calculate it. The record reports no confidence interval for maximum radiation dose and does not list a statistical analysis. Thus neither the size nor the precision of the primary endpoint can be evaluated from posted results.
These general concepts clarify what a complete statistical account might communicate, but they do not fill gaps in the registry record. The available information identifies the design, intended endpoint, and selected safety counts. It does not include the primary outcome result, analysis details, or inferential statistics needed for a fuller quantitative interpretation.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 2 outcome measures and identifies “Number of Grade 3 of Higher Toxicities” as a secondary outcome. The primary outcome is maximum radiation dose. The record does not report a multiplicity plan describing how it would handle the possibility of testing or interpreting more than one outcome. Without such a plan, the intended priority among outcomes and any adjustment for multiple statistical tests are not reported in the registry record.
No statistical analyses are listed. The registry does not report whether outcomes were analyzed according to a prespecified hierarchy, whether any outcome definitions changed, or whether analyses were adjusted for other variables. It also does not report an analysis population definition, such as which enrolled participants were included in each outcome analysis. Although enrollment is 3, the denominator contributing to the primary dose outcome is not stated.
Missing-data handling is not reported in the registry record. The record does not explain whether endpoint measurements were missing, how any missing values were treated, or whether participants with incomplete follow-up were included in analyses. It is not possible to infer that all enrolled participants contributed complete data simply from the enrollment count or the study’s completed status.
These omissions matter because analysis choices can affect the interpretation of a small pilot. For example, in general, excluding participants with missing measurements can change the group being described if missingness is related to participant characteristics or outcomes. That possibility is not evidence that missing data occurred in this trial; the registry does not report whether they did. The posted record therefore supports no conclusion about the completeness or representativeness of the endpoint analyses.
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 |
|---|---|---|---|
| Ir-192 High Dose Rate (HDR) | 0 | 3 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Ir-192 High Dose Rate (HDR) | 2 of 3 |
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 |
|---|---|
| Ir-192 High Dose Rate (HDR) | 3 of 3 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Ir-192 High Dose Rate (HDR) |
|---|---|---|
| Back Pain | Musculoskeletal and connective tissue disorders | 2 of 3 |
| Buttock Pain | Musculoskeletal and connective tissue disorders | 1 of 3 |
For the Ir-192 high dose rate group, the registry lists 3 participants at risk for serious adverse events and 0 affected. It lists 3 participants at risk for other adverse events and 3 affected. The record also lists 2 deaths. These are counts in separate registry categories; they should be read as descriptive event reporting rather than as a comparison between treatments.
The term “other adverse events” is distinct from the serious adverse-event category in the registry display. The record does not provide the event terms for that category, and no top serious-event terms are listed. It does not report the timing or causes of the deaths, or whether any death or adverse event was considered related to the intervention. The counts alone cannot establish causation or explain the clinical circumstances.
The number at risk is the recorded denominator for the corresponding category. With 3 participants enrolled, these safety counts describe a small group and cannot characterize uncommon events reliably. The registry record does not report additional detail about the safety analysis population or follow-up time for adverse events. The absence of reported serious events in this group should not be treated as proof that serious risks are absent.
12. What the Result Does, and Does Not, Mean
The study’s stated purpose was to investigate image-guided surgical navigation for placement of catheters used in Ir-192 HDR brachytherapy for previously treated metastatic or recurrent spinal and pelvic lesions. Its primary endpoint was maximum dose to the cord or cauda equina, summarized as a median and full range at 1 year. The stated dosimetric aim was cord/cauda Dmax <8 Gy. These details identify what the study set out to examine, not what it found.
The registry record does not report a numerical primary outcome result. It therefore does not show the observed dose distribution, whether the stated target was reached, or how much measurements varied. It also does not report a statistical analysis or an inferential estimate. The record cannot support a conclusion about the magnitude or precision of any dose outcome.
The design was a single-group pilot with 3 participants and no comparator. Consequently, the study cannot establish a comparative advantage over another catheter-placement method or treatment approach. The brief summary offers a rationale for image-guided navigation, including the possibility of guiding catheter placement and influencing radiation delivery, but the record does not provide outcome data demonstrating those effects.
The safety counts describe participants recorded with events and deaths, but details about timing, cause, and treatment relationship are not reported. Those counts should not be translated into claims about safety or causation. Likewise, the completed status and recorded study dates indicate registry status, not that every intended endpoint was reported.
In general, a pilot can contribute preliminary information about whether a procedure can be undertaken and what measurements might be collected. The available registry record establishes the study’s setting, design, intended dosimetric question, and limited safety counts. It does not provide the outcome values needed to determine how the approach performed. The appropriate interpretation is therefore narrow: this is a small, uncontrolled feasibility-oriented study with an unreported primary result, not evidence for a comparative treatment effect.
13. Why This Trial Matters Statistically
This trial is statistically notable for the gap between a clearly stated dosimetric question and the outcome information available in the registry record. The primary measure is specific: maximum dose to the cord or cauda equina in Gy, with a median and full range and a 1-year timeframe. The record also names a target of cord/cauda Dmax <8 Gy. Yet the observed value and range are not reported. Statistical interpretation depends not only on naming an endpoint, but also on reporting its result and the information needed to understand its precision.
The single-group design also shapes what can be learned. A pilot with 3 participants can describe experience in the enrolled group, but it cannot estimate a randomized contrast against an alternative. This distinction remains important even if a numerical dose result becomes available: a measured dose would describe the cohort and would not by itself establish that navigation caused a difference in dose or improved another clinical outcome.
The record’s specification of a median and full range signals an interest in both a typical measurement and its spread. In general, that can be useful for dose data, where a central value alone may not reveal the extremes. But neither summary is posted, and no confidence interval or analysis is listed. Readers cannot assess the degree of variability or statistical uncertainty.
The safety counts illustrate a separate reporting issue. They identify the numbers of participants with serious and other adverse events, as well as deaths, but do not give terms or causal assessments. Counts without context cannot answer whether events were related to the intervention.
Overall, the study matters statistically as an example of why design, endpoint definition, outcome reporting, and uncertainty all need to be considered together. The registry captures the intended feasibility and dosimetric aims, but the missing primary result limits the conclusions that can be drawn from the posted record.
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 contains little outcome detail for this study. Although the primary endpoint is defined as maximum radiation dose to the cord or cauda equina, the observed median and full range are not reported. The number of participants with a measured endpoint is also not reported. The stated 1-year timeframe does not establish that all participants had complete assessment at that time.
The recorded enrollment is 3, and the design is single-group. This limits the amount of information available about variation among participants and provides no concurrent comparison. The record does not report eligibility criteria in full; the arm description ends mid-sentence. Further details of treatment delivery, follow-up procedures, and how catheter placement or lesion coverage was assessed are not reported in the registry record.
No statistical analyses are listed. A statistical analysis plan, sample-size justification for the trial itself, multiplicity approach, missing-data procedures, and analysis population are not reported in the registry record. The planning assumptions describe an illustration based on two-arm equal allocation and an effect fraction, which is not the recorded single-group design. They should not be taken as evidence of observed power or as the study’s own design justification.
Safety reporting is also limited. The registry gives participant counts for serious and other adverse events and deaths, but does not list event terms, timing, causes, or relationships to treatment. These limitations leave the safety counts descriptive and prevent fuller interpretation of the primary feasibility question.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Image-Guided Navigation for High Dose Rate Temporary Interstitial Brachytherapy in the Palliative Management of Previously Treated Tumors of the Spine and Pelvis — NCT01757717.
- Registry record last updated 2018-03-20; status last verified 2017-07.
- Results first posted 2018-03-20.
- 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
This completed pilot study examined image-guided catheter placement for Ir-192 high dose rate brachytherapy in previously treated metastatic or recurrent lesions of the spine and/or pelvis. It is recorded as a single-group study with enrollment of 3, masking listed as NONE, and allocation listed as NA. The primary outcome is maximum cord/cauda dose in Gy, summarized by median and full range at 1 year; the stated aim includes cord/cauda Dmax <8 Gy.
The registry record does not report the primary outcome value, its range, or statistical analyses. It lists 0 serious adverse events among 3 at risk, other adverse events in 3 among 3 at risk, and 2 deaths; event details and relationships to treatment are not reported. The posted information describes the study’s intent and selected counts, but does not establish whether the primary dosimetric aim was achieved.