Probe Based Confocal Laser Endomicroscopy During Thoracoscopy for Pleural Malignancies Diagnosis.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Probe Based Confocal Laser Endomicroscopy During Thoracoscopy for Pleural Malignancies Diagnosis. (NCT03805971), a registered phase not stated study. The primary outcome is Pleural Carcinomatosis Identification (Compared to Standard Biopsies). Qualitative Criteria..

2. Clinical Question

The clinical motivation in the record is that live optical imaging might help identify tissue for biopsy or support earlier diagnostic decisions during thoracoscopy. Those are proposed uses, not conclusions established by the outcome information reported. The record also describes live imaging as potentially useful for observing details such as microorganisms or blood flows, but the primary endpoint concerns qualitative criteria for distinguishing benign and malignant pleura.

The question is therefore primarily one of diagnostic characterization: whether features observed with pCLE correspond to the biopsy-based classification of pleural tissue. It is not a comparison of treatment effects, and the record does not report whether use of the device changed subsequent care or patient outcomes. Any assessment of diagnostic performance would require the criterion-level results and the corresponding biopsy classifications, which are not reported in the registry record.

3. Trial Design

This was a completed study sponsored by the University of Liege. The registry record lists enrollment of 65 participants, a start date of 2018-05-22, and a primary completion date of 2019-10-15. The population was patients aged more than 18 years admitted for thoracoscopy. The brief description says that patients needing thoracoscopy were assessed regardless of indication and underwent endomicroscopy if they agreed to participate.

The intervention was study of the pleural cavity with a confocal laser endomicroscope. The device description identifies probe-based confocal laser endomicroscopy from Mauna kea technologies, used after intravenous fluorescein injection. The acquired images were compared with biopsies. The primary outcome timeframe was one day, and the stated outcome was identification of pleural carcinomatosis compared with standard biopsies using qualitative criteria.

The registry record does not describe a randomized allocation process. It explicitly indicates that this was not a randomized comparison and that allocation is not stated; any arms should not be treated as like-for-like controls. The design description instead supports reading this as an evaluation in patients undergoing thoracoscopy, with biopsy findings serving as the reference for interpreting pCLE features. Details of recruitment procedures, the number of sites, blinding, and a prespecified sample-size justification are not reported in the registry record.

The record lists five outcome measures and four analyses. It identifies quality of pCLE acquisition as a secondary outcome, but does not report its results in the information available for interpretation. The recorded enrollment and the safety denominator are not the same: enrollment is 65, while the adverse-event summary lists 62 participants at risk. The reason for this difference is not reported in the registry record. These design and reporting details matter because diagnostic accuracy depends on how participants and tissue sites were selected, how images were interpreted, and how the biopsy reference was applied.

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:

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 Pleural Carcinomatosis Identification (Compared to Standard Biopsies). Qualitative Criteria., measured over One day..

The primary endpoint is titled “Pleural Carcinomatosis Identification (Compared to Standard Biopsies). Qualitative Criteria.” Its unit is participants, its timeframe is one day, and its description says eleven preselected criteria were assessed for their ability to distinguish benign from malignant pleura. The criteria are described as qualitative variables.

In a diagnostic study, comparing an index test with a reference method is intended to assess whether test findings align with the reference classification. Here, pCLE is the index method and standard biopsies are the stated comparator or reference. Such an endpoint is relevant because the study’s central question is whether observed optical features can distinguish the two tissue categories. The registry record does not provide criterion-level counts, diagnostic accuracy estimates, or the biopsy classifications needed to examine that alignment.

As a result, the endpoint’s purpose can be described, but its observed performance cannot be evaluated from the available registry information. Sensitivity, specificity, predictive values, or other measures of diagnostic agreement are not reported in the registry record. The endpoint should not be interpreted as evidence that the device identified malignancy accurately merely because the criteria were assessed. Nor does the endpoint establish whether pCLE improved biopsy targeting, shortened time to diagnosis, or changed care; those outcomes are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Diagnostic studies compare findings from an index test with findings from a reference method. In this study, the index method was probe-based confocal laser endomicroscopy, and the stated reference was standard biopsy. The primary outcome description says qualitative pCLE criteria were assessed for their ability to distinguish benign from malignant pleura. This framing is important: the endpoint concerns classification and correspondence with biopsy findings, not a treatment effect.

What does a qualitative criterion represent?

A qualitative criterion is a feature recorded by category or description rather than as a continuous measurement. For a criterion to support diagnostic classification, its observed pattern needs to be compared across tissue categories defined by the reference method. The registry record reports that eleven preselected criteria were assessed, but does not give their definitions, the recording rules, the counts in each category, or the results. Those omissions prevent independent assessment of how consistently the criteria were applied or whether a particular feature separated benign from malignant pleura.

General statistical explanation: categorical diagnostic results can be arranged by the index test classification and the reference classification. That structure allows calculation of measures such as sensitivity, specificity, and agreement. Each measure answers a different question: sensitivity concerns detection among reference-positive observations, while specificity concerns classification among reference-negative observations. These measures depend on the definitions and the data included. None of their values can be reconstructed from the outcome description alone, and they are not reported in the registry record.

Why does the biopsy comparison matter?

A reference method gives the diagnostic comparison a stated anchor. Here, the pCLE images were compared with biopsies. In practice, interpretation depends on whether the sampled biopsy represents the tissue viewed with pCLE and whether the reference classification was applied consistently. The registry description does not report matching procedures, biopsy interpretation methods, blinding, or the handling of inconclusive findings. These methodological details are not minor: if image readers know biopsy results, or if tissue sites are not directly matched, interpretation may be affected. The presence or direction of any such influence is not reported in the registry record.

General statistical explanation: repeated images or multiple tissue sites from the same participant may be statistically related. When observations within a participant are correlated, treating each observation as independent can make uncertainty appear smaller than it is. The available outcome description uses participants as the unit but does not explain the structure of image-level or biopsy-level observations. It is therefore not possible to determine whether analyses accounted for clustering or whether the reported counts were participant-level summaries.

What can a count show?

The primary outcome is described as a count of participants, with qualitative variables presented for the criteria. Counts show how many observations fall into recorded categories, but the registry information available does not include the actual counts. Even when counts are available, their interpretation depends on the denominator: a count without knowing how many participants contributed can be misleading. Here, the enrollment is 65, while the safety summary uses 62 at risk; the primary endpoint denominator is not stated in the registry information considered.

General statistical explanation: uncertainty around a diagnostic estimate is commonly expressed with a confidence interval. The estimate gives a central summary, while the interval conveys the range of values compatible with the data under the chosen statistical procedure. A narrow interval generally indicates greater precision than a wide interval, although interpretation also depends on design and assumptions. Neither estimates nor confidence intervals for the qualitative criteria are reported in the registry record, so no claim about precision is possible.

How should the planning illustration be read?

The sample-size assumptions describe a planning illustration computed from the observed effect, rather than the trial’s own design. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a stated fraction of the observed effect. These assumptions define a hypothetical calculation framework; they do not show that participants were randomized or that the trial recruited two comparable arms. The record explicitly says the study was not a randomized comparison and that allocation is not stated.

General statistical explanation: sample-size planning asks how many observations a proposed study would need to have a chosen probability of detecting an effect of a specified size under particular assumptions. A planning illustration depends on the assumed effect and statistical model. It is not a measure of the probability that the observed finding is true, and it is not observed power. Since the numerical planning outputs and the observed diagnostic effect are not reported in the registry information considered, the illustration cannot be evaluated quantitatively.

General statistical explanation: over-dispersion occurs when observed variability exceeds what a statistical model assumes. In count-based analyses, ignoring extra variability can lead to uncertainty estimates that are too small. The registry description does not identify a count model or report evidence of over-dispersion, so this issue cannot be assessed for the trial. More broadly, statistical methods should follow the data structure and outcome scale; the registry record does not describe enough analysis detail to judge that match.

What do the listed analyses establish?

The record lists four analyses and five outcome measures, but the available information does not report their numerical results or full methods. The analysis plan, handling of missing observations, and any adjustments are not reported in the registry record. It is therefore not possible to determine whether analyses were prespecified, whether all criteria were analyzed as intended, or how multiple criterion-level findings were interpreted. These uncertainties concern reporting and cannot be resolved by treating the mere listing of analyses as evidence of a particular result.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome description identifies eleven preselected qualitative criteria, and the registry lists five outcome measures and four analyses. Assessing several criteria creates a multiplicity issue: when many hypotheses are examined, the chance of at least one apparently notable result can increase. General statistical explanation: multiplicity can be addressed through prespecified primary comparisons, adjustment procedures, or cautious interpretation of exploratory findings. The registry record does not report whether any multiplicity strategy was planned or applied, so the status of adjustment is not reported in the registry record.

The registry information does not provide criterion-level result values, the number of observations analyzed for each criterion, or an account of missing observations. It is therefore not possible to determine whether all enrolled participants contributed to the primary endpoint, whether images or biopsies were unevaluable, or how incomplete records were handled. The reason the safety summary lists 62 participants at risk while enrollment is 65 is also not reported in the registry record.

The analysis population is not defined in enough detail to identify whether the primary results used all enrolled participants, only participants with interpretable pCLE and biopsy findings, or another subset. The record also does not report an intention-to-diagnose approach or a missing-data sensitivity analysis. These are reporting gaps, not evidence that any particular method was or was not used. Without denominators and missingness information, the completeness and potential selection effects of the diagnostic results cannot be evaluated.

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 1% reporting threshold.

The registry’s adverse-event summary lists one group, “Patient Aged More Than 18 Years Admitted for Thoracoscopy,” with 62 participants at risk. It records zero serious adverse events, zero other adverse events, and zero deaths. These are counts as entered in the registry record; they should be read alongside the stated denominator rather than as a general guarantee of safety.

The enrollment is 65, which differs from the safety denominator of 62. The reason for that difference is not reported in the registry record. The record does not describe the safety observation period, the method used to solicit or collect events, or whether every enrolled participant was monitored in the same way. It also does not provide further serious-event categories or event-level narratives.

General statistical explanation: an observed count of zero does not establish that the underlying risk is zero. The amount of uncertainty around a zero count depends on the number of people observed and the completeness and duration of ascertainment. No interval estimate is reported in the registry record. Accordingly, the safety figures describe the recorded events in the listed group, but they do not support a broader claim that adverse events could not occur.

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

The registry record describes a diagnostic evaluation of pCLE during thoracoscopy. Its primary question was whether eleven preselected qualitative criteria could distinguish benign from malignant pleura when compared with standard biopsies. The recorded enrollment was 65, and the study is marked completed. These registry entries describe the scope and status of the work; they do not reveal how well the criteria performed.

The registry information considered does not report the criterion-level findings, diagnostic estimates, confidence intervals, or the number of participants contributing to each analysis. It therefore does not establish whether any pCLE feature agreed with biopsy classification, how precise an estimate might be, or whether the criteria differed between tissue categories. The endpoint’s stated purpose should not be mistaken for a positive diagnostic result.

The record describes possible clinical motivations, including helping to target biopsies or supporting earlier diagnosis. It does not report whether pCLE changed biopsy decisions, accelerated diagnosis, led to therapeutic intervention, or improved patient outcomes. Those questions require outcomes beyond the presence of an imaging procedure and a comparison with biopsy findings.

The safety summary records zero serious adverse events, zero other adverse events, and zero deaths among 62 participants at risk. It does not explain why this denominator differs from enrollment or provide the safety collection details needed to interpret completeness. These figures should be understood as registry counts rather than proof that the procedure carries no risk.

Overall, the record identifies a clinically relevant diagnostic question and the intended comparison, but its reported information is insufficient to establish diagnostic accuracy or clinical benefit. The absence of detailed results is a limit on what can be concluded, not evidence that the technique did or did not perform well.

13. Why This Trial Matters Statistically

This trial is statistically interesting because it addresses a diagnostic technology in a setting where the record says usefulness had not been established. pCLE produces live optical imaging, and the study compares qualitative image features with biopsy findings during thoracoscopy. That setup brings together questions about classification, reference standards, and the unit of analysis, all of which are central to interpreting diagnostic research.

The endpoint description also highlights why clear reporting matters. Eleven preselected criteria were assessed, yet criterion-level results and denominators are not reported in the registry information considered. Without those data, readers cannot judge whether the criteria were informative, whether results were consistent, or how much uncertainty surrounded any estimate. Listing the questions evaluated is not a substitute for reporting the evidence answering them.

General statistical explanation: diagnostic assessments can be sensitive to participant selection, disease mix, interpretation procedures, and how index-test observations are paired with the reference method. Reporting these details helps readers understand the setting in which performance was evaluated and whether it might apply elsewhere. The registry record does not report several of these methodological details, including the image-reading procedures and matching of pCLE observations to biopsy sites.

The record also illustrates the distinction between an exploratory diagnostic rationale and a demonstrated clinical impact. The proposed uses include targeting biopsies and supporting earlier diagnosis, but neither is reported as an outcome. A future evaluation of clinical impact would need to measure whether decisions or patient outcomes changed, not just whether image features were assessed against biopsies.

Finally, the discrepancy between enrollment and the safety denominator, together with the absence of a stated primary analysis population, makes denominator reporting particularly important. Clear participant flow, outcome-specific counts, and analysis methods would strengthen interpretation of both diagnostic and safety findings.

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.

Important trial-specific limitations arise from the amount of detail reported in the registry record. Although the primary outcome description names eleven preselected qualitative criteria, the results for those criteria are not reported in the registry information considered. Counts, diagnostic accuracy measures, confidence intervals, and outcome-specific denominators are unavailable, preventing assessment of the endpoint’s observed performance and precision.

The record does not report how pCLE images were interpreted, whether readers were blinded to biopsy findings, how biopsy sites were matched to imaged areas, or how unevaluable images and inconclusive biopsies were handled. These details affect the credibility and reproducibility of a diagnostic comparison. Their absence from the registry information does not establish that the procedures were not used, only that they are not reported in the registry record.

The study is not described as randomized, allocation is not stated, and the record cautions against treating arms as like-for-like controls. This is relevant because the study should be interpreted as a diagnostic evaluation rather than as a randomized treatment comparison. The distribution of thoracoscopy indications and the prevalence of malignant findings are not reported, limiting assessment of how representative the evaluated population may be.

Enrollment was 65, while the safety summary lists 62 participants at risk. The reason for the difference is not reported in the registry record. The analysis population for the primary outcome, missing-data handling, and participant flow through the diagnostic comparison are also not reported. The record lists multiple outcomes and analyses but does not state whether multiplicity was addressed. These reporting limits constrain conclusions about diagnostic performance, generalizability, and safety completeness.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Probe Based Confocal Laser Endomicroscopy During Thoracoscopy for Pleural Malignancies Diagnosis. — NCT03805971.
• Registry record last updated 2020-04-03; status last verified 2020-03.
• Results first posted 2020-04-03.
• 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

NCT03805971 is a completed study titled “Probe Based Confocal Laser Endomicroscopy During Thoracoscopy for Pleural Malignancies Diagnosis.” The sponsor is the University of Liege. The record lists enrollment of 65, a start date of 2018-05-22, and a primary completion date of 2019-10-15.

Adults admitted for thoracoscopy underwent pleural cavity imaging with probe-based confocal laser endomicroscopy after intravenous fluorescein injection. Images were compared with biopsies. The primary outcome concerns qualitative criteria for identifying pleural carcinomatosis compared with standard biopsies, with a one-day timeframe. The description states that eleven criteria were assessed; their results are not reported in the registry record. Quality of pCLE acquisition is listed as a secondary outcome.

The safety summary lists 62 participants at risk, with zero serious adverse events, zero other adverse events, and zero deaths. The reason for the difference between this denominator and enrollment is not reported. The registry record does not describe a randomized comparison, and allocation is not stated.