Feasibility of Performing Peripheral Pulmonary Lesion Biopsy Using Robotic Bronchoscopy-Guided Cryoprobe: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Feasibility of Performing Peripheral Pulmonary Lesion Biopsy Using Robotic Bronchoscopy-Guided Cryoprobe (NCT05399082), a randomized na study. The primary outcome is Ability to Successfully Obtain Sample.

2. Clinical Question

The study focuses on the feasibility and biopsy quality of using a miniature cryoprobe during robotic bronchoscopy. In this crossover design, the biopsy methods are performed in different orders: standard forceps followed by research cryoprobe, or research cryoprobe followed by standard forceps. Randomized allocation concerns those sequences; the registry lists no masking.

The primary endpoint is a count of tissue samples judged adequate for further pathological analysis, rather than a patient-level measure of diagnosis or a direct measure of clinical benefit. The registry also lists secondary outcomes concerning procedure duration, cryoprobe freezing time, successful biopsy attempts, histological accessibility and diagnostic yield, total histological area, and pathological artifacts. The record does not report the population characteristics needed to determine how broadly the findings apply.

3. Trial Design

This completed study is registered as a randomized, unmasked crossover trial sponsored by Mayo Clinic. It concerns biopsy of peripheral pulmonary lesions using robotic bronchoscopy. The registry lists the phase as NA and enrollment as 30. The study started on 2022-08-15, and primary completion is recorded as 2023-07-11.

The intervention descriptions specify two procedure sequences. One sequence performs standard forceps biopsy first and research cryoprobe biopsy second; the other performs research cryoprobe biopsy first and standard forceps biopsy second. The cryoprobe is described as a 1.1mm disposable device passed through the working channel of the Ion Robotic bronchoscope. The registry describes the participants as people already scheduled for lung-lesion biopsy using robotic bronchoscopy as part of standard care.

Because both biopsy procedures are included in the crossover design, the sequence is an important part of the study description. The posted results list 30 observations for Standard Forceps Biopsy and 30 for Research Cryoprobe Biopsy. Those entries do not, by themselves, show how within-participant pairing, sequence, or period was handled in an analysis. The statistical analysis plan for those features is not reported in the registry record.

The record lists ten outcome measures and nine posted secondary outcomes. It does not describe the randomization procedure, allocation concealment, eligibility criteria, participant characteristics, or any masking beyond recording that the study was unmasked. It also does not report an analysis population definition or explain whether every enrolled participant completed both procedures. The posted record therefore supports a description of the design and its stated outcomes, but not a detailed reconstruction of how the trial was conducted or analyzed.

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.

First Intervention

Second Intervention

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.

6. Primary Endpoint

The registry lists the primary outcome as Ability to Successfully Obtain Sample, measured over Baseline.

The primary endpoint is titled “Ability to Successfully Obtain Sample.” It measures the number of tissue samples that the bronchoscopist considers adequate for further pathological analysis. The registry gives the unit as tissue samples and describes the timeframe as Baseline. The outcome is recorded separately for Standard Forceps Biopsy and Research Cryoprobe Biopsy.

In general, an adequacy measure addresses whether collected material is judged suitable for a stated downstream purpose. In this study, that purpose is further pathological analysis. This makes the endpoint relevant to the stated feasibility and biopsy-quality question: obtaining tissue is not the only consideration if the material cannot be assessed pathologically. The endpoint is not itself a patient-level diagnostic outcome, nor does the registry define it as evidence that a lesion was correctly diagnosed.

The posted values are 123.0 tissue samples for Standard Forceps Biopsy and 130.0 tissue samples for Research Cryoprobe Biopsy, with 30 listed for each. These are aggregate counts in the registry record. The record does not report how the counts are distributed across participants, how adequacy was operationalized beyond the bronchoscopist’s judgment, or whether a blinded assessment was used. It also does not report an inferential comparison, confidence interval, or analysis accounting for the crossover structure. The counts therefore describe the posted endpoint values but do not establish the precision or statistical significance of a difference between methods.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The appropriate reading of these results depends on the endpoint’s structure and on the crossover design. The registry lists aggregate counts for the two biopsy methods, but it does not report an analysis that compares them. The following statistical concepts are general explanations; they are not claims about analyses performed in this study unless explicitly stated.

What does the primary count represent?

The endpoint counts tissue samples judged adequate for further pathological analysis. A count is not interchangeable with a proportion or an average per participant. To interpret a count as a participant-level success measure, a reader would need to know how many samples were collected from each participant and how adequacy was distributed. Those details are not reported in the registry record. The listed counts, 123.0 and 130.0, describe the posted totals for the two procedure labels, while the registry lists 30 observations for each.

Counts can have different statistical behavior depending on how they arise. In general, a count may vary more than a simple model assumes, especially when observations differ substantially between people or when events cluster. Over-dispersion means that variability exceeds what a particular count model expects. It matters because an analysis that underestimates variability can produce confidence intervals that are too narrow and tests that are too optimistic. The registry record does not report a count model, a dispersion estimate, or a model diagnostic for this endpoint.

Why does crossover matter?

In a crossover design, participants receive more than one study procedure, usually in an assigned order. Measurements from the same person are often correlated. General statistical practice is to account for this pairing rather than treat all measurements as if they came from unrelated people. Pairing can improve precision when within-person measurements are meaningfully related, but the analysis must preserve the participant-level links. The registry record does not report the paired endpoint data or the statistical method used to account for them.

Order can also matter. A procedure performed first may differ from one performed second because of timing, prior sampling, or other period-related conditions. These are general considerations in crossover studies, not documented effects in this trial. The registry records the two possible orders but does not report whether sequence or period effects were assessed, or how they were handled statistically.

What would an effect estimate and confidence interval add?

In general, an effect estimate quantifies the contrast between treatments on a defined scale. A confidence interval describes uncertainty around that estimate under the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, but it does not by itself establish clinical importance. For this endpoint, a meaningful estimate would need to specify the comparison scale and account for the crossover structure and count distribution. No such estimate or confidence interval is reported in the registry record.

A p-value, when reported, addresses compatibility between observed data and a specified null model under the analysis assumptions. It does not measure the size or importance of an effect, and it does not resolve limitations in the design or measurement. The registry record does not report a p-value for the primary endpoint. It also lists zero analyses, so no registry-posted inferential analysis is available in this record.

How should planning illustrations be understood?

General sample-size planning asks how many participants may be needed to detect a specified effect under stated assumptions. The registry describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation; the effect to detect is a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not evidence that the trial had a particular probability of finding a result. The registry record does not report the trial’s own sample-size justification or design calculation. No specific planning sample-size values are included in the registry record for this explanation, so none can be interpreted.

Planning based on an observed effect is also conditional on that effect being a useful estimate for future planning. General statistical reasoning cautions that estimates from small studies may be imprecise. The registry record does not provide an uncertainty interval for the observed endpoint or an independent estimate for planning. The planning assumptions therefore should not be confused with a registered or demonstrated design rationale.

Why are no recalculated comparisons presented?

A simple unadjusted recalculation can sometimes be made from summary statistics, but the information needed depends on the endpoint and design. Here the primary outcome is a count, and the record explicitly indicates that values are missing or not estimable for a two-arm comparison for this endpoint type. The crossover pairing is also not available in the aggregate summaries. A recalculated treatment contrast, standard error, confidence interval, or p-value would therefore not be justified from the posted values alone. The sponsor’s own analysis does not take precedence in this case because the discrepancy indicator is false, but the registry record still does not provide an analysis to interpret.

More generally, model choice should follow the data structure and the prespecified question. A participant-level paired analysis, a count regression model, or another approach would each require information and assumptions not documented in the registry record. It would be inappropriate to select one retrospectively based only on the two aggregate counts. The posted descriptive values can be stated plainly, while inferential conclusions remain unavailable from the record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists ten outcome measures and nine posted secondary outcomes. The secondary outcomes include procedure duration, cryoprobe freezing time, successful biopsy attempts, histological accessibility grade, histological diagnostic yield, total histological area, crush artifacts, and other pathologic artifacts. The primary endpoint is the count of tissue samples considered adequate for further pathological analysis.

When a study evaluates multiple outcomes, general statistical practice recognizes a multiplicity concern: the more hypotheses tested, the greater the chance that at least one result may appear notable by chance if tests are interpreted separately. Approaches to address this can include prespecifying a hierarchy, adjusting significance thresholds, or treating secondary outcomes as exploratory. The registry record does not report a multiplicity strategy, a hierarchy among outcomes, or which outcomes were intended to be confirmatory.

The registry record lists zero analyses. It therefore does not provide inferential results for the primary or secondary outcomes in this record. A statistical analysis plan, including any prespecified handling of multiple outcomes, is not reported in the registry record. No adjustment method or set of primary hypotheses should be inferred from the outcome list alone.

Missing-data handling and analysis populations are also not reported in the registry record. The record does not describe whether all enrolled participants completed both procedures, how incomplete procedures or missing measurements were handled, or whether analyses used an intention-to-treat, per-protocol, or other population. These omissions matter particularly for a crossover study, where incomplete paired observations can affect which data contribute to a comparison. The listed observation counts do not establish that all participants contributed complete paired data.

Without a reported analysis plan, missing-data account, and defined analysis population, the aggregate endpoint counts cannot be used to reconstruct a complete inferential analysis. The registry record supports a description of the registered outcomes and posted counts, but not conclusions about multiplicity-adjusted evidence or the effect of missing data.

11. 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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports serious adverse events for Standard Forceps Biopsy and Research Cryoprobe Biopsy separately. For each procedure, 30 participants are listed as at risk, zero serious adverse events are reported, and zero deaths are reported. The record also lists other adverse events for the two procedures: 3 for Standard Forceps Biopsy and 2 for Research Cryoprobe Biopsy.

These are descriptive figures from the registry record. Zero reported serious adverse events means none are recorded in these entries; it does not establish that the true risk is zero. In general, the precision of safety estimates depends on the amount and quality of follow-up and on how events are collected and classified. Follow-up duration, event definitions, and the statistical method for comparing safety are not reported in the registry record.

The other-adverse-event counts are not characterized further in the record, and no event terms are listed among the top serious adverse-event terms. These figures should not be treated as a formal comparison between procedures: the crossover structure, participant-level event histories, timing, and method of attribution are not described. The registry record does not report a statistical safety analysis.

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

The posted results establish that the registry record contains aggregate primary-endpoint counts of 123.0 adequate tissue samples for Standard Forceps Biopsy and 130.0 for Research Cryoprobe Biopsy, with 30 listed for each procedure. These values describe the samples judged by the bronchoscopist adequate for further pathological analysis. They are not a complete account of how many participants had adequate tissue, how many samples each participant contributed, or how the two procedures compared within participants.

The record describes a randomized crossover study designed to evaluate feasibility and biopsy quality. That design provides a framework for comparing two procedures in different orders, but a design label is not itself an analysis. The registry record does not report a treatment-effect estimate, confidence interval, p-value, or analysis of paired outcomes. It therefore does not establish whether the observed aggregate counts reflect a reliable difference between methods.

The counts also do not show whether either procedure produced a correct diagnosis, improved clinical outcomes, or was preferred by participants or clinicians. Although the registry lists diagnostic yield and other pathology-related secondary outcomes, their results are not reported in the registry record for this explanation. The primary count should not be used as a substitute for those outcomes.

The safety entries report zero serious adverse events and zero deaths for both procedure groups, alongside other-adverse-event counts of 3 and 2. These observations describe the registry entries, but they do not demonstrate absence of risk or establish a comparative safety conclusion. The record does not report enough information about event definitions, follow-up, or analysis to support broader safety claims.

Overall, the registry offers a descriptive snapshot of a feasibility study’s primary count and safety entries. It does not support a conclusion that one biopsy method is better, equivalent, or worse, and it does not establish generalizability beyond the study population, whose detailed characteristics are not reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically notable because it combines a count endpoint with a crossover design. Each feature shapes how the results should be analyzed and interpreted. Counts of adequate samples describe the amount of material judged suitable for pathology, but they do not directly express a participant-level chance of obtaining adequate tissue. A statistical comparison needs a clearly defined unit of analysis and information about how samples are distributed among participants.

The crossover design makes participant-level linkage important. When the same participant receives both procedures, the observations may be related. General analysis methods for paired data can use that relationship, but aggregate procedure totals do not retain the pairing. The registry record identifies different procedure orders yet does not report the paired results or explain how sequence was handled. This limits what can be inferred from the posted counts.

The case also illustrates the distinction between registered outcomes and reported analyses. The registry lists primary and secondary measures, but lists zero analyses. An outcome list communicates what was to be assessed; it does not supply effect estimates, uncertainty intervals, or evidence of a difference. Statistical interpretation depends on those results and on the methods used to obtain them.

Finally, feasibility and biopsy quality are multidimensional. Adequate sample counts are one aspect, while procedure duration, successful attempts, histological accessibility, diagnostic yield, sample area, and artifacts address other aspects named in the registry. The record’s outcome list makes those distinctions visible, but the registry entries do not include results for those secondary measures. Keeping each outcome separate prevents an aggregate count from being treated as a complete measure of procedural performance.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The primary limitation for interpretation is that the registry reports aggregate sample counts without a treatment-effect estimate or inferential analysis. The record does not report the participant-level distribution of samples, paired outcomes, variability, or a confidence interval. Consequently, the precision of the primary result and the magnitude of a within-participant contrast cannot be assessed from these entries.

The crossover design raises additional questions that the registry record does not answer. The record does not report how sequence or period was handled, whether both procedures were completed by every participant, or how incomplete pairs were treated. It also does not describe randomization procedures beyond listing randomized allocation. Allocation concealment and any operational protections against assessment bias are not reported; masking is listed as none.

The endpoint relies on the bronchoscopist’s judgment that a sample is adequate for further pathological analysis. The record does not define a more detailed adequacy rubric or report whether assessment was independently reviewed. Participant characteristics, eligibility criteria, and the setting details needed to assess generalizability are not reported in the registry record.

The registry lists secondary outcomes but does not provide their results in the registry record for this explanation. It also does not report a multiplicity plan, missing-data methods, analysis populations, sample-size justification, or a statistical analysis plan. These gaps limit evaluation of outcome selection, uncertainty, and possible bias. The safety entries are similarly limited by the absence of event definitions, follow-up details, and a comparative safety analysis.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Feasibility of Performing Peripheral Pulmonary Lesion Biopsy Using Robotic Bronchoscopy-Guided Cryoprobe — NCT05399082.
• Registry record last updated 2024-10-17; status last verified 2024-10.
• Results first posted 2024-10-17.
• 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.

18. Record Summary

The registry record describes a completed randomized, unmasked crossover study of robotic bronchoscopy-guided miniature cryoprobe biopsy and standard forceps biopsy for peripheral pulmonary lesions. Enrollment is 30. The two sequences perform forceps then cryoprobe, or cryoprobe then forceps.

The primary endpoint is the number of tissue samples considered by the bronchoscopist adequate for further pathological analysis. The posted aggregate counts are 123.0 for Standard Forceps Biopsy and 130.0 for Research Cryoprobe Biopsy, with 30 listed for each. No inferential comparison or uncertainty estimate is reported in the registry record.

The registry lists ten outcome measures, nine posted secondary outcomes, and zero analyses. Safety entries report zero serious adverse events and zero deaths for each procedure group; other adverse-event counts are 3 and 2. The record does not report a statistical analysis plan, missing-data methods, analysis populations, or detailed participant characteristics.