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 Spect Analysis of Cardiac Perfusion Changes After Whole Breast/Chest Wall Radiation Therapy With ABC (NCT00321048), a randomized na study. The primary outcome is Efficacy of Active Breathing Coordinator (ABC) Device as Determined by the Mean Apical Perfusion Score.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00321048 |
| Phase | NA |
| Condition | Breast Neoplasms, Carcinoma, Ductal, Adenocarcinoma |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 57 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes women receiving radiation for breast cancer. The primary-outcome description specifies patients with left breast cancer. The conditions listed include Breast Neoplasms, Carcinoma, Ductal, and Adenocarcinoma. The record does not provide further eligibility details or a fuller description of the population included in the endpoint analysis.
Intervention
The intervention was radiation therapy using the Active Breathing Coordinator (ABC) device. The device was intended to reduce radiation exposure to the heart. The registry describes cardiac perfusion assessment at baseline and six months after treatment for patients assigned to this arm.
Comparator
The control arm received radiation therapy without ABC. The record describes the same baseline and six-month cardiac perfusion assessments for this arm, allowing a comparison of changes between the randomized groups.
Primary question
The study asked whether cardiac perfusion, measured by the mean apical perfusion score on SPECT, changed differently after radiation with ABC than after radiation without ABC. The outcome timeframe was baseline before radiation to six months after radiation. Although the registry identifies this as the primary outcome, it does not report a numerical result for the comparison.
3. Trial Design
This was a randomized, parallel-group trial with no masking listed in the registry. Participants were assigned to radiation therapy with the Active Breathing Coordinator (ABC) or radiation therapy without ABC. The registry labels the phase as NA and the study status as completed. Enrollment was 57.
The trial’s stated purpose was to quantify cardiac perfusion changes, or lack of changes, after radiation for breast cancer while using ABC, with a control group receiving radiation without the device. The rationale in the registry is that cardiac perfusion changes have been seen after whole breast or chest wall irradiation and that ABC theoretically decreases radiation exposure to the heart. This rationale describes the question being tested; it does not establish that the device altered exposure or perfusion in this trial.
The primary outcome was the change in mean apical perfusion score measured by SPECT from baseline before radiation to six months after treatment. The registry describes assessment at both time points in both arms. It does not report the number of participants contributing primary-outcome data at either assessment, or the numbers analyzed in each arm. Those details are not reported in the registry record.
The trial was sponsored by Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins. The recorded start was 2006-06 and primary completion was 2010-01. The record does not describe allocation procedures beyond labeling the study randomized, nor does it give details about how randomization was generated or concealed. Those details 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.
Overall Study
| Stage | Active Breathing Coordination | No Active Breathing Coordination |
|---|---|---|
| STARTED | 28 | 29 |
| COMPLETED | 22 | 21 |
| NOT COMPLETED | 6 | 8 |
Reasons for not completing this period:
| Reason | Active Breathing Coordination | No Active Breathing Coordination |
|---|---|---|
| Withdrawal by Subject | 6 | 8 |
Analysis population for the primary outcome, as defined in the registry: We understand the reporting score on a scale however, in this case the Mean Perfusion Score was utilized.
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: Baseline characteristics were only collected for participants who completed study interventions.
| Characteristic | Unit | Active Breathing Coordination | No Active Breathing Coordination | Total |
|---|---|---|---|---|
| Participants analysed | 22 | 21 | 43 | |
| Age, Continuous | years | 52.8 (20 to 86) | 58.7 (35 to 85) | 55.8 (20 to 86) |
| Sex: Female, Male: Female | Participants | 22 | 21 | 43 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | Participants | 22 | 21 | 43 |
6. Primary Endpoint
The registry lists the primary outcome as Efficacy of Active Breathing Coordinator (ABC) Device as Determined by the Mean Apical Perfusion Score, measured over Baseline (pre-radiation) to 6 months (post-radiation).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Mean Perfusion Score |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was the change in mean apical perfusion score measured by SPECT from baseline before radiation to six months after radiation. The registry describes this measure as an assessment of cardiac perfusion, used to examine whether perfusion changed after treatment and whether the pattern differed between the ABC and no-ABC arms.
The score uses ordered categories: 1 represents an equivocal or mild reduction in perfusion, 2 a moderately reduced perfusion, 3 a severely reduced perfusion, and 4 absent perfusion. The registry says that the mean perfusion score was used. This makes the outcome a summary of the scores, rather than a report of each category separately.
As a general statistical point, a mean can condense measurements into a single group summary, while also concealing how individual scores are distributed across categories. Interpreting a change in the mean therefore benefits from seeing group-level results and a measure of variability. The registry identifies standard deviation as the dispersion measure, but it does not report the arm-specific endpoint means or standard deviations, nor a numerical between-arm estimate. These results are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry defines a clear comparison: randomized participants received radiation therapy with ABC or without ABC, and cardiac perfusion was assessed before radiation and six months after treatment. The primary outcome was the change in mean apical perfusion score on SPECT. However, the registry does not provide numerical outcome values for either arm or a numerical comparison between arms. The direction and size of any difference in perfusion change therefore cannot be determined from the registry record.
The outcome description gives a scale from 1 to 4, with larger values corresponding to more severely reduced or absent perfusion. The scale also includes an equivocal or mild reduction at 1. Without observed scores, group means, or variability, the scale definition alone does not show what participants experienced or whether the randomized groups differed. The registry also does not report a confidence interval or p-value for a between-arm effect. Those results are not reported in the registry record.
Randomization is intended to support a fair comparison of groups by balancing, on average, characteristics that could affect the outcome. The registry identifies the allocation as randomized, but does not describe the sequence-generation or concealment procedures. More importantly for interpretation of the result, a randomized design cannot substitute for reporting the endpoint data and the analysis. The numerical primary-outcome comparison is not reported in the registry record.
The posted safety information lists zero serious events and zero other events in the at-risk counts for each arm, alongside deaths recorded separately. These figures describe the registry’s adverse-event entries, not the unreported perfusion outcome. The record gives no causes or timing for the deaths, and no information linking them to treatment. It is therefore not possible to use these entries to explain or qualify a cardiac-perfusion comparison.
Overall, the registry allows the trial question, design, endpoint, and some safety counts to be described, but not the primary efficacy result. No conclusion about the comparative change in cardiac perfusion can be drawn from the registry record without the arm-level endpoint values and an analysis of the between-arm difference.
9. Statistical Methods Explained
What does randomization contribute?
Random allocation is designed to make the treatment groups comparable, on average, with respect to both measured and unmeasured characteristics. In this trial, the randomized contrast was radiation with ABC versus radiation without ABC. The registry reports the randomized design and parallel-group model, but does not describe the method used to generate the allocation sequence or conceal assignments. Those details are not reported in the registry record.
Randomization does not ensure that the realized groups are identical, particularly in a trial of this size, and it does not by itself establish what happened to the endpoint. A valid interpretation still requires outcome observations, a stated comparison, and appropriate handling of participants who do not contribute complete data. The registry does not provide the numerical primary-outcome comparison or describe the analysis population.
How should a baseline-to-follow-up change be compared?
The outcome was assessed at baseline and six months after treatment. A change score represents the follow-up value relative to the baseline value for a participant. A comparison of changes between randomized arms asks whether the average pattern from baseline to follow-up differed between groups. General statistical practice may also compare follow-up outcomes while accounting for baseline values, but the registry does not say which approach was used. The analysis method is not reported in the registry record.
For a continuous outcome reported as a mean, standard deviation describes the spread of participant measurements around the group mean. It helps readers judge how variable the observations are, but it does not by itself quantify uncertainty in the estimated difference between groups. A confidence interval is a range of estimates compatible with the data and the statistical model; it conveys the precision of an estimate. The registry identifies standard deviation as the dispersion measure but gives no observed means, standard deviations, effect estimate, or confidence interval for the primary comparison.
What would a between-arm estimate mean?
A between-arm estimate would summarize the difference in the endpoint change for participants assigned to ABC compared with participants assigned to no ABC. Its interpretation depends on how change was defined, which participants were included, how missing assessments were handled, and what model or test was used. These analytical details are not reported in the registry record. No unadjusted recalculation can be made from the posted information because arm-specific outcome summaries are absent.
A p-value, if reported, would describe how compatible the data are with a specified null model under the assumptions of the test. It would not measure the size or clinical importance of an effect. A confidence interval would add information about precision and a range of plausible effect estimates under the model. Neither a p-value nor a confidence interval for the primary outcome is reported in the registry record. Thus the trial’s statistical evidence for a difference cannot be assessed from the outcome results posted there.
How does the score affect interpretation?
The endpoint is expressed as a mean of scores on an ordered scale. The categories distinguish levels of reduced perfusion, from equivocal or mild reduction to absent perfusion. As a general statistical consideration, calculating a mean from ordered categories treats the distances between adjacent score values as numerically meaningful. That summary may be useful, but it can mask whether a group’s average reflects small shifts across many participants or substantial changes in a smaller number. Category counts or individual-level distributions would provide complementary context. Such details are not reported in the registry record.
The registry’s endpoint description names SPECT as the measurement method and gives the score definitions, but does not report further information about score reading, reproducibility, or assessor masking. The study is listed as having no masking. The record does not specify whether outcome assessors were masked separately from participants or study personnel. These measurement details are not reported in the registry record.
What can be said about sample size and analysis planning?
The registry records enrollment of 57, but enrollment alone does not establish how many participants contributed measurements at baseline and follow-up or were included in an analysis. The endpoint-analysis counts and any sample-size justification are not reported in the registry record. Without observed outcome values and variability, the precision of the primary comparison cannot be evaluated.
In general, a sample-size calculation is a planning exercise based on assumptions about the effect to detect, outcome variability, and statistical error rates. It is not an observed result and does not show whether a trial found an effect. The registry does not report the trial’s own sample-size rationale or statistical analysis plan. Interim analyses and stopping rules are also not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome measure, but its reporting note indicates that the primary outcome has several categories or time points and was not reduced to one comparison. Consequently, there is no single numerical primary-outcome estimate available in the record to interpret. The registry does not explain how any multiple categories or time points were handled analytically, or whether any multiplicity adjustment was planned. These details are not reported in the registry record.
Multiplicity matters when several outcomes, time points, or comparisons are tested, because considering many results can increase the chance of finding an apparently unusual result by chance. General approaches include defining one primary comparison in advance or adjusting inference across a family of tests. The registry does not provide enough information to determine whether such an approach was used. No p-values or primary comparison estimates are reported.
Missing outcome data can affect both the representativeness of the analyzed participants and the estimated treatment contrast. The record describes assessments at baseline and six months, but does not report how many participants completed each assessment, the reasons for missing measurements, or any method for handling missing data. Those details are not reported in the registry record.
The analysis population is also not described. It is not reported whether the primary analysis followed randomized assignment for all participants, included only participants with observed measurements, or used another definition. The registry does not report an analysis plan, adjustment variables, or the handling of protocol deviations. These omissions limit assessment of how the result was obtained; the numerical primary outcome 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 |
|---|---|---|---|
| Active Breathing Coordination | 0 | 22 | 0.0% |
| No Active Breathing Coordination | 0 | 21 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Active Breathing Coordination | 2 of 22 |
| No Active Breathing Coordination | 1 of 21 |
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 |
|---|---|
| Active Breathing Coordination | 0 of 22 |
| No Active Breathing Coordination | 0 of 21 |
The registry lists the Active Breathing Coordination arm with 22 participants at risk for serious adverse events and 0 affected. It lists 22 at risk for other adverse events and 0 affected. The No Active Breathing Coordination arm lists 21 participants at risk for serious adverse events and 0 affected, and 21 at risk for other adverse events and 0 affected. These are the counts recorded in the adverse-event information.
Deaths are listed separately: 2 in the ABC arm and 1 in the no-ABC arm. The registry does not provide causes, timing, or treatment relationship for these deaths. The at-risk denominators in the adverse-event listing should not be taken as proof of the number assessed for the primary perfusion outcome; those endpoint analysis counts are not reported in the registry record.
A zero count in a registry category means that no events were recorded in that category for the listed group. It does not establish that no health events of any kind occurred, nor does it identify how events were defined or collected. The registry lists no serious adverse-event terms. Further details about event definitions, follow-up duration, and attribution are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The trial addresses a focused statistical question: whether the change in SPECT-measured cardiac perfusion from baseline to six months after radiation differed between participants randomized to radiation with ABC and those randomized to radiation without ABC. The registry identifies the outcome and describes how its score categories correspond to levels of reduced perfusion.
That description is not a numerical result. The registry record does not report arm-specific mean perfusion scores, standard deviations, a between-arm estimate, a confidence interval, or a p-value. Accordingly, the posted information does not establish the direction, magnitude, or precision of a difference in cardiac perfusion change. It also does not show whether the result was statistically distinguishable from no difference.
The record’s rationale says ABC theoretically decreases radiation exposure to the heart. This is a proposed rationale, not a reported finding from the trial. The registry does not provide radiation exposure measurements or a numerical cardiac-perfusion comparison that would test whether the intended effect was observed. The recorded safety counts are separate from the primary endpoint and do not fill that gap.
Even if a difference in mean score were available, its interpretation would depend on the score distribution, missing follow-up data, analysis method, and uncertainty around the estimate. A mean can summarize an ordered score while obscuring the frequency of each category. The registry does not report the details needed to assess those considerations. It is therefore appropriate to distinguish the study’s question and design from the result: the question is described, but the numerical primary outcome is not reported in the registry record.
The information supports no treatment recommendation. It describes a randomized comparison and the posted outcomes, while leaving the main comparative endpoint unavailable for evaluation. Further outcome reporting would be needed to assess the size and precision of the between-arm change.
13. Why This Trial Matters Statistically
This trial is statistically notable for pairing random allocation with a repeated measurement of cardiac perfusion before and after radiation. That structure frames the comparison around change over time, rather than relying only on a single post-treatment score. The two randomized arms also make the key contrast explicit: radiation with ABC versus radiation without the device.
The endpoint illustrates a common challenge in clinical research: a biological measurement may be recorded using ordered categories and then summarized by a mean. The registry defines categories from equivocal or mild reduction to absent perfusion and states that a mean score was used. Such a summary can make group comparisons concise, but interpretation benefits from the underlying distribution and a clear account of how change was analyzed. Neither the category-level results nor the numerical group comparison is reported in the registry record.
The record also illustrates why design information and outcome reporting serve different purposes. Randomization describes how the study was intended to compare groups; it does not reveal the observed endpoint values. Without the estimated difference and its precision, readers cannot judge whether the comparison is compatible with a wide range of effects or is estimated more narrowly. Those results are not reported in the registry record.
Finally, safety entries and efficacy outcomes answer different questions. The adverse-event listing gives counts for serious events, other events, and deaths, but cannot substitute for the primary perfusion analysis. Keeping these evidence types separate helps prevent a descriptive safety count from being mistaken for evidence about the endpoint. The record is useful for identifying the study question and design, while its missing primary comparison limits statistical interpretation.
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 principal limitation for interpreting this trial from the registry is that the numerical primary-outcome comparison is not reported. The record gives the endpoint definition and assessment timeframe but no arm-specific means, standard deviations, change estimates, confidence intervals, or p-values. Without these, the magnitude, direction, and precision of the result cannot be assessed.
The registry notes that the primary outcome has several categories or time points and was not reduced to one comparison. It does not explain the intended primary contrast or how those categories and time points were analyzed. This leaves uncertainty about the exact estimand—the quantity the analysis was intended to estimate—and about how the reported score would map to a group comparison.
Important analysis details are absent: the number of participants with outcome measurements, the analysis population, handling of missing observations, and statistical model or test. The randomization procedure and concealment details are also not reported in the registry record. The no-masking designation is listed, but the record does not clarify whether outcome assessment was masked separately or describe score-reading procedures.
The endpoint uses a mean score across ordered categories. Without category distributions, it is difficult to tell how the average relates to individual score patterns. The registry does not report measurement reproducibility or other details that would clarify how consistently the score was assessed. The recorded enrollment of 57 does not resolve how many participants contributed to the primary analysis.
Finally, the safety listing provides counts but little context: causes and timing of deaths, event definitions, follow-up duration, and attribution are not reported in the registry record. These gaps limit interpretation of both outcome and safety information, without establishing that any particular result or event was absent beyond the listed counts.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Spect Analysis of Cardiac Perfusion Changes After Whole Breast/Chest Wall Radiation Therapy With ABC — NCT00321048.
- Registry record last updated 2025-02-28; status last verified 2025-02.
- Results first posted 2019-06-19.
- 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
NCT00321048 is a completed randomized, parallel-group trial with no masking listed. It compared radiation therapy with the Active Breathing Coordinator against radiation therapy without ABC. Enrollment was 57; the recorded start was 2006-06 and primary completion was 2010-01. The sponsor was Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins.
The primary outcome was the change in mean apical perfusion score measured by SPECT from baseline before radiation to six months after treatment. The score categories range from equivocal or mild reduction to absent perfusion. The registry does not report numerical primary-outcome results or the analysis details needed to evaluate a between-arm comparison. The safety listing reports zero serious and zero other adverse events in the stated at-risk counts for each arm, and separately records 2 deaths in the ABC arm and 1 in the no-ABC arm.