POWER Study (Prospective Transbronchial Microwave + Robotic-Assisted Bronchoscopy): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for POWER Study (Prospective Transbronchial Microwave + Robotic-Assisted Bronchoscopy) (NCT05299606), a non-randomized na study. The primary outcome is Number of Patients Whose Ablation Resulted in Technique Efficacy.

2. Clinical Question

In statistical terms, the primary endpoint is a participant count based on a binary classification: each analyzed participant either meets the imaging definition or does not. The clinical question is therefore about the observed frequency of the prespecified imaging result in the treated group, not about a treatment effect relative to a comparator. Without a reported endpoint count, the registry record does not establish the observed frequency or its precision.

3. Trial Design

The POWER Study is described as a prospective, multicenter, single-arm study. Its registry allocation is non-randomized, masking is none, and the model is single-group. These design features mean that participants are not assigned at random between treatment groups and that there is no concurrent control arm for estimating a between-group contrast. The study evaluates transbronchial microwave ablation of oligometastatic tumors in the peripheral lung.

The intervention is a device procedure using the NEUWAVE FLEX Microwave Ablation System and Accessories, guided by the Auris MONARCH Platform for visualization and access. Cone beam CT is used to confirm probe tip placement and the final ablation zone. The registry lists the intervention type as a device. It records an enrollment of 12; this should be read as the registry enrollment figure, not as the denominator for every outcome.

The primary endpoint is technique efficacy, assessed using CT imaging at 30 days post-ablation. The detailed timeframe is 30 days (- 7 to +14 days) after the ablation procedure. The primary endpoint population is described as patients analyzed at 30 days post-ablation. The record states that 11 patients were analyzed because 1 patient passed away before the 30 day post-ablation visit.

The recorded start date is 2022-10-21, the primary completion date is 2024-10-18, and the current status is terminated. The reason for termination is not reported in the registry record. The registry does not report a phase beyond NA. It also does not report the rationale for the enrollment figure, the planned duration of follow-up beyond the endpoint descriptions, or a detailed statistical analysis plan.

Several additional outcomes are listed: technical success, local tumor progression, disease progression, and repeat ablation of the target lesion. Their numerical results are not reported in the registry record. The primary endpoint result is also not reported, so the design and endpoint definitions can be described, but the observed efficacy findings cannot be assessed from 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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Patients analyzed at 30 days post-ablation. 11 patients were analyzed as 1 patient passed away before the 30 day post-ablation visit.

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: 12 patients were enrolled and treated

6. Primary Endpoint

The registry lists the primary outcome as Number of Patients Whose Ablation Resulted in Technique Efficacy, measured over 30 days post-ablation.

The primary endpoint is the number of participants whose ablation resulted in technique efficacy. The registry defines technique efficacy as ablation of the target tumor or tumors with the ablation zone completely overlapping or encompassing the entire target tumor or tumors, as assessed using CT imaging at 30 days (- 7 to +14 days) after the ablation procedure.

This endpoint turns an imaging assessment into a participant-level classification. For each patient included in the endpoint analysis, the CT assessment determines whether the defined spatial relationship between the ablation zone and target tumor is present. A count can describe how many analyzed participants met the criterion, while a proportion can describe that count relative to the endpoint denominator. The registry record gives the endpoint population as 11 patients analyzed and explains that 1 patient died before the 30 day post-ablation visit. However, the number meeting the technique-efficacy definition is not reported in the registry record.

As a general statistical point, a prespecified imaging endpoint can make the primary assessment concrete and reproducible when the imaging criteria and assessment timing are clearly defined. It focuses on a technical and radiographic result rather than directly measuring a broader patient outcome. Interpretation depends on the reliability of the imaging assessment, the consistency of the assessment process, and the handling of participants without an evaluable scan. Details about assessor masking or adjudication are not reported in the registry record.

The endpoint is an observed outcome in a single treated group. Without a comparator, it cannot by itself quantify how the result differs from what would have occurred under another treatment or no intervention. The absence of a reported endpoint count also prevents assessment of the observed frequency and its statistical precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count represent?

The primary outcome is a count of participants meeting a binary definition. A binary outcome classifies each participant into one of two categories for the endpoint: the imaging criterion is met, or it is not. The count is meaningful only in relation to the population assessed. The registry describes 11 patients as analyzed at the primary endpoint and identifies 1 patient who died before the scheduled post-ablation visit. The number meeting the endpoint is not reported in the registry record, so a count or rate cannot be interpreted.

As a general concept, a proportion is a count divided by the number of participants with an outcome assessment. That denominator should match the stated analysis population and endpoint rules. Different denominators can arise when some participants lack an assessment or are otherwise excluded from an analysis. No extra denominator should be inferred from enrollment alone. Here, the primary endpoint population is explicitly described, but the observed endpoint count and the detailed analysis rules are not reported.

What would uncertainty around a binary outcome tell readers?

In general, a confidence interval expresses uncertainty in an estimated quantity. For a binary outcome, it can convey how precisely the observed proportion estimates an underlying event frequency, subject to the statistical method and its assumptions. A wider interval indicates less precision; a narrower interval indicates greater precision. An interval does not guarantee that the true value lies within it, and it does not repair limitations such as selection bias or the absence of a comparison group.

No confidence interval for technique efficacy is reported in the registry record. Without the endpoint count and corresponding estimate, precision cannot be evaluated. No p-value or hypothesis test for the primary endpoint is reported either. The record lists 0 analyses, so there is no registered analysis result to interpret as evidence from a formal test.

Why does the single-group design matter?

In general, random allocation helps balance both measured and unmeasured characteristics across comparison groups, on average. This study is listed as non-randomized and single-group, with no masking. It therefore provides no randomized comparison. A result within the treated group can describe what was observed after the procedure, but it cannot show how that outcome compares with a control group under the same study conditions.

Without a concurrent comparator, the result is also vulnerable to factors that may influence outcomes independently of the intervention. These can include underlying disease characteristics, other care, the timing of assessment, and decisions about additional treatment. This is a general limitation of single-group outcome interpretation, not evidence that any particular factor affected this study.

What can be inferred from the imaging definition?

The endpoint specifies a CT-based assessment of whether the ablation zone completely overlaps or encompasses the target tumor or tumors. Explicit criteria can improve interpretability by defining the success classification in advance. The endpoint is nevertheless a technical imaging measure. It does not, by itself, establish longer-term tumor control, survival, quality of life, or comparative benefit. Those are distinct outcomes and should not be inferred from the endpoint label.

The assessment window is 30 days (- 7 to +14 days) after the procedure. As a general matter, a defined window helps standardize when outcome status is assessed. The record does not report details about image review procedures, assessor masking, adjudication, or the handling of ambiguous scans. Those details matter because measurement and classification decisions can affect a binary endpoint.

How should the planning assumptions be read?

General sample-size calculations can be used to illustrate how a future study's required enrollment might depend on assumptions about significance level, allocation, effect size, and statistical method. The planning assumptions recorded for this material specify a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. For time-to-event outcomes, the assumption describes total events; for other outcomes, it describes participants per arm.

These are planning assumptions, not evidence about the observed endpoint and not the study's own design rationale. The POWER Study is single-group, so an equal allocation between two arms does not describe its recorded trial design. A planning illustration does not demonstrate that the study had a particular power, and it must not be called observed power. No numerical sample-size justification or detailed statistical plan is reported in the registry record. The observed effect referenced by planning assumptions is not reported in the registry record, so readers cannot evaluate the assumptions against a posted primary result.

More broadly, the registry record does not report a model for the primary outcome, covariate adjustment, interim analyses, missing-data imputation, or a multiplicity procedure. These methods should not be presumed. In general, such choices shape the interpretation of estimates and tests, especially when a study includes several outcomes or incomplete follow-up. Where the record does not describe a choice, the appropriate reading is that the method is not reported in the registry record.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Transbronchial Microwave Ablation")
n      <- c(11)
events <- c(11)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Transbronchial Microwave Ablation  11  11  100.0  71.5  100.0  74.1  100.0  73.5  99.8

11. Multiplicity, Missing Data and Analysis Populations

The record lists 5 outcome measures, including the primary technique-efficacy outcome and secondary outcomes for technical success, local tumor progression, disease progression, and repeat ablation of the target lesion. It lists 0 analyses. Numerical results for the primary and secondary outcomes are not reported in the registry record.

When a study evaluates several outcomes, general statistical practice distinguishes the primary question from secondary or exploratory questions. Testing many outcomes can increase the chance of obtaining at least one apparently notable result by chance. A multiplicity strategy may address that issue, but the registry record does not report a multiplicity procedure or a detailed statistical analysis plan. No adjustment should be assumed, and no unadjusted or adjusted significance finding is available to interpret.

The registry describes 11 patients analyzed for the primary endpoint and states that 1 patient passed away before the 30 day post-ablation visit. The record does not report imputation or other missing-data methods, nor does it give further detail about missing imaging assessments or analysis-population rules. A death before assessment is not equivalent to an observed imaging result; the registry's stated primary analysis population excludes that patient from the endpoint assessment.

As a general matter, missing outcome data can affect interpretation when the reasons for missingness are related to the outcome or to participant characteristics. The extent and direction of any such effect cannot be determined from the available record. The registry also does not report sensitivity analyses that might examine alternative assumptions about missing outcomes. Consequently, the stated analyzed population can be described, but robustness to missing-data assumptions cannot be assessed.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 2% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: post-ablation syndrome (8.3%), pneumonia (8.3%), jaundice cholestatic (8.3%), pyrexia (8.3%), hemoptysis (8.3%).

The safety record lists 12 participants at risk for both serious and other adverse events. It records serious adverse events affecting 4 participants and other adverse events affecting 9 participants. The record also lists 1 death. These are descriptive counts for the treated group, not comparisons against a control group.

The serious adverse event terms listed among the top terms are post-ablation syndrome, pneumonia, jaundice cholestatic, pyrexia, and hemoptysis, each reported as 8.3%. These term-specific percentages should be read as registry entries, not added together. A participant may experience more than one event, and the record does not establish that the listed terms are mutually exclusive or attributable to the procedure.

In general, a serious adverse event classification describes seriousness under the applicable reporting framework; it is distinct from whether an event was caused by the intervention. The registry figures do not by themselves establish causality. The study has no control group for estimating a comparative risk, and the record does not provide the circumstances or attribution assessment for each event. The death is recorded, but its cause or relationship to the procedure is not reported in the registry record. These data therefore describe recorded safety events without supporting a comparative or causal conclusion.

13. What the Result Does, and Does Not, Mean

The registry record establishes that the study evaluated transbronchial microwave ablation in a prospective, multicenter, single-group setting and defined a CT-based primary endpoint at 30 days post-ablation. It also specifies the endpoint population and records that 11 patients were analyzed, with 1 patient passing away before the 30 day post-ablation visit. Those details describe the design and analysis context.

The record does not report the number of participants meeting the technique-efficacy definition. It therefore does not show the observed primary outcome frequency, its precision, or whether the endpoint was met by any particular proportion of the analyzed group. The secondary outcome titles also do not establish their results, which are not reported in the registry record.

The study's single-group design does not support a randomized comparison with another intervention or usual care. In general, outcomes after a procedure can be influenced by several factors, and a treated-group observation alone cannot separate those influences from an intervention effect. No comparative treatment-effect estimate is reported. Nor does the technical imaging endpoint alone establish longer-term disease control or other patient outcomes.

The safety figures describe events recorded in the treated group: 4 participants with serious adverse events, 9 with other adverse events, and 1 death. These figures should not be interpreted as proof that the procedure caused the events, nor can they show how safety compares with an alternative. The record does not report event attribution details or a comparison group.

The status is terminated, but the reason is not reported in the registry record. Taken together, the record allows readers to understand what was intended to be assessed and some descriptive safety information, while leaving the primary efficacy result, secondary outcome findings, and formal statistical analyses unavailable. No claim of benefit, lack of benefit, or comparative safety follows from the endpoint definition or the status alone.

14. Why This Trial Matters Statistically

This study raises statistical questions that are especially important for small, single-group device studies. The record lists an enrollment of 12 and an analyzed primary endpoint population of 11. With a limited endpoint population, any observed binary outcome would need to be interpreted in light of its precision as well as its count. Here, however, the primary endpoint result is not reported, so neither the outcome frequency nor its uncertainty can be assessed.

The endpoint is defined using a concrete imaging criterion: the ablation zone must completely overlap or encompass the target tumor or tumors on CT assessment at 30 days post-ablation. This makes the measurement target explicit. At the same time, a technical imaging endpoint answers a narrower question than whether a treatment changes disease course or patient health. Distinguishing those questions is central to sound statistical interpretation.

The design also matters. Non-randomized, single-group studies can describe observed outcomes and help characterize feasibility or procedural experience, but they lack a concurrent randomized control for estimating comparative effects. The absence of masking can also matter for outcome assessment, although details about image review and assessor procedures are not reported in the registry record.

Finally, the posted record illustrates why endpoint definitions, analysis populations, and outcome results must be read separately. A clearly defined outcome is not a reported finding; an enrollment figure is not a primary endpoint denominator; and a safety count is not a comparative risk estimate. The record includes some population and safety information, but the primary and secondary outcome results and the statistical analyses are not reported. That distinction is essential when assessing what the evidence can support.

15. 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 efficacy is that the primary technique-efficacy result is not reported in the registry record. Although the definition and assessment window are specified, there is no count of participants meeting the criterion and no estimate of its precision. Results for the listed secondary outcomes are also not reported.

The study is single-group and non-randomized, with no comparator arm. It cannot provide a randomized estimate of a difference between the intervention and another treatment or no intervention. The record also indicates no masking. Whether imaging assessors were masked or whether images underwent independent review is not reported in the registry record.

The endpoint population is stated as 11 patients analyzed, while enrollment is recorded as 12; the record explains that 1 patient passed away before the 30 day post-ablation visit. Further missing-data rules, imputation, sensitivity analyses, or details of analysis-population definitions are not reported. The impact of the unavailable endpoint assessment cannot be determined from the record.

The registry lists 0 analyses and does not report a detailed statistical plan, sample-size justification, interim analyses, or a multiplicity approach. The status is terminated, but the reason for termination is not reported. These omissions limit assessment of the study's planned inference, the interpretation of multiple outcomes, and the context for the reported enrollment.

Safety information is also descriptive rather than comparative. The record gives serious and other adverse-event counts and lists serious event terms, but event attribution and the cause or relationship of the death are not reported. The small single-group setting limits what can be concluded about comparative safety from these figures.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: POWER Study (Prospective Transbronchial Microwave + Robotic-Assisted Bronchoscopy) — NCT05299606.
• Registry record last updated 2025-11-24; status last verified 2025-11.
• Results first posted 2025-11-24.
• 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.

19. Record Summary

The POWER Study is a prospective, multicenter, non-randomized, single-group study of transbronchial microwave ablation for oligometastatic tumors in the peripheral lung. The intervention uses the NEUWAVE FLEX Microwave Ablation System and Accessories with the Auris MONARCH Platform; cone beam CT is used to confirm probe placement and the final ablation zone.

The primary endpoint is technique efficacy on CT imaging at 30 days post-ablation, defined by complete overlap or encompassing of the target tumor or tumors by the ablation zone. The record states that 11 patients were analyzed and that 1 patient died before the 30 day visit. The primary endpoint result and secondary outcome results are not reported in the registry record.

The safety record lists 4 participants with serious adverse events, 9 with other adverse events, and 1 death. The study status is terminated; the reason is not reported. The registry lists 0 analyses.