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 Mini Invasive Endomicroscopy of the Pleura for Malignancies Diagnosis (NCT04731129), a registered phase not stated study. The primary outcome is Malignant Pleural Infiltration Identification.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04731129 |
| Phase | Phase not stated |
| Condition | Pleural Diseases, Pleural Neoplasms |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 59 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Liege |
| Results posted | Yes |
2. Clinical Question
Population
Patients referred to an endoscopy unit for medical thoracoscopy because of pleural disease. The registry lists Pleural Diseases and Pleural Neoplasms as conditions. Enrollment was 59 participants; the safety population is listed as 52.
Intervention
Probe-based confocal laser endomicroscopy of the pleura. Before thoracoscopy, the probe was to be introduced through a Boutin's needle or thoracentesis catheter. The study also describes acquisition during thoracoscopy, with the probe passed through the thoracoscope's working channel under visual control.
Comparator
The study describes comparing mini-invasive probe findings with probe acquisitions made during medical thoracoscopy, with histological samples, and across investigators. This is not a randomized comparison; allocation is not stated. The registry does not describe a like-for-like control arm.
Primary question
Can pre-thoracoscopy pleural probe findings identify or exclude malignant infiltration, and do selected pleural features occur with different frequencies in malignant and benign involvement? The stated primary outcome is malignant pleural infiltration identification, measured as a count of participants over one day. The registry objective also includes comparing mini-invasive and thoracoscopy acquisitions, histology, and investigator interpretations.
3. Trial Design
The registry describes a prospective trial of probe-based confocal laser endomicroscopy in patients referred for medical thoracoscopy. It lists University of Liege as the sponsor and the study status as COMPLETED. The recorded start date is 2020-12-15 and the primary completion date is 2023-09-15. Enrollment is 59.
The procedure was planned in stages. Before medical thoracoscopy, the probe was to be introduced through a Boutin's needle or thoracentesis catheter. Two experienced clinicians, described as unblinded and aware of each patient's medical history, were to assess the acquisition during the procedure. A further acquisition during thoracoscopy was to be made through the thoracoscope's working channel under visual control. The registry says ten criteria were to be assessed prospectively, with findings compared against thoracoscopy acquisitions and histological samples. It also describes comparing interpretations by different investigators.
This is not a randomized comparison, and allocation is not stated. The registry does not describe a concurrent control arm or a treatment assignment. The clinical question is therefore about the diagnostic observations and comparisons within the study, not a randomized estimate of a treatment effect. Details such as eligibility criteria, recruitment flow, the full protocol, and the statistical analysis plan 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 | Patients Referred to Medical Throacoscopy for Treatment or Exploration of a Pleural Effusion |
|---|---|
| STARTED | 59 |
| COMPLETED | 52 |
| NOT COMPLETED | 7 |
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 | Patients Referred to Medical Throacoscopy for Treatment or Exploration of a Pleural Effusion |
|---|---|---|
| Participants analysed | 52 | |
| Age, Continuous | years | 67 (SD 8.5) |
| Sex: Female, Male: Female | Participants | 24 |
| Sex: Female, Male: Male | Participants | 28 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: Belgium | participants | 52 |
6. Primary Endpoint
The registry lists the primary outcome as Malignant Pleural Infiltration Identification, measured over one day.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary outcome is titled Malignant Pleural Infiltration Identification. Its unit is participants, its parameter is a count of participants, and its timeframe is one day. The registry description says that the pre-thoracoscopy probe acquisition would be assessed by two experienced, unblinded clinicians who were aware of the patient's medical history. The objective was to determine whether preselected criteria were present with significantly different frequencies in malignant and benign pleural involvement.
A participant count can describe how many people meet an outcome definition. To understand such a count, readers generally also need the outcome definition, the number of participants assessed, and how missing or indeterminate assessments were handled. Those details are not reported in the registry record for this endpoint. The record does not give observed malignant and benign group counts, criterion-specific results, an effect estimate, a confidence interval, or a p-value. It therefore does not establish from the posted results how frequently identification occurred or how precisely any difference between groups was estimated.
Comparing the pre-thoracoscopy assessment with thoracoscopy findings and histology is relevant to the stated diagnostic objective because these are distinct sources of observations. The registry record does not specify the reference standard or the detailed rules for classifying a result as identifying or excluding infiltration.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study's purpose and general approach, but it does not report the primary endpoint's observed results. Although the stated objective was to assess whether selected probe features occurred with different frequencies in malignant and benign pleural involvement, no group counts, frequency estimates, uncertainty intervals, or test results are included in the record. Consequently, no direction or magnitude of a diagnostic difference can be described from the posted results.
The record says the study planned comparisons among mini-invasive probe acquisitions, acquisitions during thoracoscopy, histological samples, and investigator interpretations. It does not report the resulting agreement, diagnostic classification, or comparison statistics. The registry lists three outcome measures and eight analyses, but their detailed results and methods are not reported in the registry record. The number of planned criteria is stated as ten; the full criteria are not available in the record excerpt, which begins a description of abnormal tissue architecture and then ends before the list is complete.
As a general statistical principle, a difference in observed frequencies is more informative when accompanied by an effect estimate and an uncertainty interval. A confidence interval describes the range of estimates reasonably compatible with the observed data under the method's assumptions; it does not, by itself, establish clinical usefulness. A p-value, when reported, addresses compatibility with a specified null model rather than the probability that a method is correct. Neither kind of result is available for the primary outcome in the registry record.
The study is listed as completed, with enrollment of 59. The safety data list 52 participants at risk and zero affected by serious adverse events, with zero deaths. Those safety figures do not substitute for diagnostic outcome results. The record does not explain the difference between the enrollment and safety counts, nor does it state how many participants contributed evaluable primary outcome data. No conclusion about diagnostic performance, agreement with histology, or the precision of estimates can be drawn without those results and denominators.
The registry also states that the assessing clinicians were unblinded and aware of medical history. This is relevant context for interpreting subjective image assessments: knowledge of clinical information can influence classification. The record does not say whether any safeguards or independent adjudication procedures were used. These omissions limit interpretation of the planned comparisons, but they do not establish that bias occurred.
9. Statistical Methods Explained
The statistical methods used for the primary outcome are not reported in the registry record. The stated objective refers to comparing frequencies of selected criteria in malignant and benign pleural involvement, but the record does not identify the test, model, estimate, confidence interval, or decision threshold used. The following concepts are general explanations of how such analyses are commonly interpreted; they are not claims about the methods used in this study.
What does a participant count represent?
A count records the number of participants meeting a specified outcome definition. A count alone is difficult to interpret without a denominator: the number assessed and eligible to contribute to that outcome. A proportion or rate can place a count in context, but no such values should be inferred in the absence of reported denominators and results. The primary outcome is described as a count of participants, and its timeframe is one day. The registry does not provide the endpoint's operational definition or the observed count.
How should frequency comparisons be understood?
In general, comparing a feature's frequency between groups requires knowing how participants were classified, how many were assessed in each group, and whether observations were independent. A statistical test may evaluate whether observed differences are compatible with a null hypothesis, while an effect estimate describes the size and direction of the contrast. An uncertainty interval indicates the precision of that estimate under the method's assumptions. The registry's stated aim is to assess significantly different frequencies, but the method for testing that aim and the resulting estimates are not reported.
The registry describes multiple related observations: an acquisition before thoracoscopy, an acquisition during thoracoscopy, histological samples, and interpretations by different investigators. These comparisons answer distinct questions. Comparing acquisition routes concerns how findings differ across procedures; comparing findings with histology concerns diagnostic classification against tissue samples; comparing investigators concerns consistency of interpretation. The record does not specify the statistical methods or results for any of these comparisons.
Why can blinding and classification matter?
In general, blinding can reduce the influence of knowledge about other findings on an assessment. Here, the registry explicitly describes the two clinicians assessing pre-thoracoscopy acquisitions as unblinded and aware of medical history. That fact is relevant when interpreting a judgment-based assessment. It does not, on its own, quantify bias or prove that an assessment was incorrect. The registry record does not report whether assessors worked independently, how disagreements were resolved, or whether image classifications were checked against a prespecified procedure.
Classification rules also matter. A finding needs a defined interpretation, including how uncertain, missing, or technically inadequate acquisitions are treated. The summary identifies ten criteria and begins to describe abnormal tissue architecture, but the available description is incomplete. The full criteria, thresholds, and handling rules are not reported in the registry record.
What do the planning assumptions mean?
The planning illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes an effect to detect as a stated fraction of the observed effect. These are assumptions for a planning calculation, not evidence that the trial was designed with those assumptions or that its analysis used them. The registry does not report the trial's own sample-size justification. In addition, the study is not a randomized comparison, and its allocation is not stated; equal allocation between two arms in a planning illustration should not be read as a description of the enrolled study.
General sample-size planning asks how many observations would be needed to detect a chosen effect under specified assumptions. A planning illustration based on an observed effect is not observed power and does not establish the reliability of an estimate. No calculated planning values are described in the registry record. Nor does the record state whether any interim analyses were planned or performed.
What can be said about uncertainty?
General statistical reporting pairs an estimate with information about its uncertainty and makes the analysis population clear. That allows readers to distinguish a precisely estimated result from one compatible with a wide range of values. The posted registry information does not give primary outcome estimates or uncertainty intervals. The safety counts are descriptive counts; without additional information, they do not provide an estimate of the frequency of unreported diagnostic outcomes. The registry record also does not report whether adjusted analyses were performed or what covariates, if any, were considered.
10. Multiplicity, Missing Data and Analysis Populations
The registry describes ten criteria to be assessed and lists three outcome measures and eight analyses. The detailed analysis plan, full outcome definitions, and analysis results are not reported in the registry record. It is therefore unclear which comparisons were designated primary beyond the named primary outcome, how the criteria map to the listed outcomes and analyses, or whether any approach to multiple testing was planned. When many features or comparisons are examined, the chance of finding an apparently notable result by chance can increase; methods such as prespecified testing hierarchies or multiplicity adjustments may address this issue in general. The record does not state whether such methods were used.
Missing-data handling is also not reported. The record gives enrollment of 59 and safety counts for a population of 52, but does not explain the difference or identify the number included in the primary outcome analysis. It does not state whether participants with missing, incomplete, or uninterpretable acquisitions were excluded, retained in a category, or handled using another method. No assumptions about missing outcomes or sensitivity analyses should be inferred.
The registry does not report the analysis populations, such as which participants were considered eligible for each endpoint or comparison. Nor does it describe a protocol deviations policy, analysis set definitions, or whether all enrolled participants were included in the primary analysis. These details matter because the denominator and the rules for inclusion affect how participant counts and diagnostic comparisons are interpreted.
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 |
|---|---|---|---|
| The Entire Studied Population | 0 | 52 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| The Entire Studied Population | 0 of 52 |
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 |
|---|---|
| The Entire Studied Population | 0 of 52 |
The registry reports safety data for “The Entire Studied Population,” with 52 participants at risk. The serious adverse event count is zero, and the number affected is zero; the listed number of deaths is also zero. The other adverse event fields likewise list 52 at risk and zero affected. No serious adverse event terms are listed.
These are descriptive registry counts. They indicate what the record reports for the stated safety population; they do not describe diagnostic performance or answer the primary endpoint question. The registry does not explain why the safety population is 52 while enrollment is 59, give further details on safety surveillance, or report whether all participants had the same duration of observation. The primary outcome timeframe is one day, but that is not stated as the safety follow-up period. The absence of reported events in these fields should not be generalized beyond the population and information recorded.
12. What the Result Does, and Does Not, Mean
The registry describes a prospective study intended to evaluate mini-invasive pleural probe-based confocal laser endomicroscopy in patients referred for medical thoracoscopy. It sets out comparisons with acquisitions during thoracoscopy, histological samples, and interpretations by different investigators. It also specifies a primary outcome focused on malignant pleural infiltration identification and an objective of comparing selected feature frequencies in malignant and benign involvement.
What the record does not establish is the observed diagnostic result. No primary outcome counts, group-specific frequencies, effect estimates, confidence intervals, p-values, or agreement results are reported. Without these, the magnitude, direction, and precision of any diagnostic comparison cannot be assessed. The completion status and enrollment count do not fill that gap, and the safety counts are not a substitute for efficacy or diagnostic findings.
The record also does not establish how well a mini-invasive acquisition corresponds to histology, how consistently investigators interpret images, or whether the method changes clinical decisions. Those are questions related to the study's stated objectives, but their results are not reported. The summary identifies unblinded assessments by clinicians aware of medical history, an important consideration for interpretation, while leaving other assessment procedures unclear.
In general, a diagnostic study's interpretation depends on clear outcome definitions, complete denominators, appropriate reference comparisons, and uncertainty estimates. This record lacks the outcome-level data needed to evaluate those elements. The planned comparisons should therefore be distinguished from demonstrated findings: a registry description of what investigators intended to assess is not itself evidence of the resulting diagnostic accuracy or clinical value.
13. Why This Trial Matters Statistically
This study addresses a statistical problem that can arise when a new diagnostic imaging approach is intended for use through a less invasive route. The registry describes comparing pre-thoracoscopy probe acquisitions with acquisitions made during thoracoscopy, histological samples, and investigator interpretations. Statistically, these are related but distinct comparisons, and their interpretation depends on explicit classifications, denominators, and analysis methods.
The record also highlights the importance of assessor blinding in image-based evaluation. The clinicians assessing the pre-thoracoscopy acquisition were described as unblinded and aware of medical history. In general, this information helps readers consider whether judgments may be influenced by clinical context. It does not show that bias occurred, but it makes reporting of classification procedures, independent reads, and disagreement resolution particularly relevant. Those details are not reported in the registry record.
Multiplicity is another consideration. Ten criteria were to be assessed, while the registry lists multiple outcomes and analyses. Without a prespecified plan or complete results, readers cannot determine how the study handled the many possible comparisons or distinguish confirmatory findings from exploratory ones. This matters even when the objective is descriptive, because interpretation can depend on which features were selected and how uncertainty was assessed.
Finally, the difference between enrollment of 59 and a safety population of 52 illustrates why clear analysis populations and participant flow are important. The record does not reconcile those counts or state the primary outcome denominator. The missing outcome results prevent assessment of the diagnostic question, but the design description still makes clear which reporting details are necessary for a transparent 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 available registry record does not include the primary outcome results, diagnostic comparison estimates, uncertainty intervals, or p-values. It therefore cannot support an assessment of the magnitude or precision of the stated diagnostic objective. The registry lists three outcome measures and eight analyses, but detailed results and methods for them are not reported.
The study description says two experienced clinicians were unblinded and aware of medical history when assessing pre-thoracoscopy acquisitions. The record does not explain whether their assessments were independent, how disagreements were handled, or whether another procedure was used to limit assessment bias. It also does not provide the complete list and operational definitions of the ten criteria; the available criterion description is incomplete.
Although enrollment is 59, the safety population is 52. The registry does not account for the difference or report the number with evaluable primary outcome data. Eligibility details, participant flow, missing-data methods, and analysis population definitions are not reported. The record also does not specify the reference-standard classification procedure or how histological findings were linked to probe assessments.
The study is not described as a randomized comparison, and allocation is not stated. Its findings, if reported elsewhere, would need interpretation in light of its diagnostic comparison design rather than as a randomized treatment effect. The registry does not report its own sample-size justification, interim analysis plan, or statistical analysis plan. These limitations concern what can be concluded from the registry record; they do not establish that the full study report contains no further information.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Mini Invasive Endomicroscopy of the Pleura for Malignancies Diagnosis — NCT04731129.
- Registry record last updated 2025-01-10; status last verified 2024-11.
- Results first posted 2025-01-10.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry record describes NCT04731129, “Mini Invasive Endomicroscopy of the Pleura for Malignancies Diagnosis,” sponsored by University of Liege. It is listed as COMPLETED, with a start date of 2020-12-15, primary completion date of 2023-09-15, and enrollment of 59.
The prospective study concerned probe-based confocal laser endomicroscopy of the pleura in patients referred for medical thoracoscopy. The primary outcome was Malignant Pleural Infiltration Identification, measured as a participant count over one day. The stated aims included assessing selected features before thoracoscopy and comparing findings with thoracoscopy acquisitions, histological samples, and investigator interpretations.
The record reports zero serious adverse events among 52 participants at risk and zero deaths. It does not report primary outcome results, detailed statistical methods, or an explanation for the difference between enrollment and the safety population.