Tranexamic Acid in Radical Resection and Endoprosthetic Reconstruction: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Tranexamic Acid in Radical Resection and Endoprosthetic Reconstruction (NCT04347122), a randomized phase 4 study. The primary outcome is Perioperative Blood Loss.

2. Clinical Question

3. Trial Design

The registry identifies this as a randomized, single-masked, parallel-group Phase 4 trial sponsored by the University of Kansas Medical Center. Its title concerns tranexamic acid in radical resection and endoprosthetic reconstruction. The study status is terminated. The record lists a start date of 2020-01-28 and a primary completion date of 2023-08-18, but it does not report why the study was terminated or give further information about the timing of recruitment and follow-up.

Four arms separate the surgical setting and TXA use: bony tumor surgery with TXA, bony tumor surgery without TXA, soft tissue sarcoma surgery with TXA, and soft tissue sarcoma surgery without TXA. The bony tumor descriptions refer to resection of the femur or proximal tibia and endoprosthetic reconstruction. The soft tissue arms refer to lower-extremity sarcoma resection. This structure matters when interpreting the outcome: the registry does not reduce the study to one comparison, and results should not be treated as if all tumor types and procedures formed a single homogeneous group.

The registry lists an enrollment of 12. For the primary blood-loss outcome, it reports no participants in the bony-tumor TXA group, while the other three arms have reported results. It identifies one outcome measure and no secondary outcomes. The record does not report the randomization procedure, allocation concealment, the identity of the person or people masked, treatment adherence, or details of the intended analysis plan. Those omissions limit how much can be said about the conduct of the trial beyond its registered design labels.

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: Bony tumor w/ TXA group had no participants

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: Enrollment was terminated, study was closed due to low enrollment, therefore no data were analyzed.

6. Primary Endpoint

The registry lists the primary outcome as Perioperative Blood Loss, measured over During surgical procedure, 4 to 6 hours.

The primary endpoint is perioperative blood loss, recorded in mL. The registry describes it as the amount of blood lost during the surgical process and gives the timeframe as “During surgical procedure, 4 to 6 hours.” It labels the endpoint parameter as a mean and its dispersion as full range. Therefore, the listed central values should be read as the registry’s reported mean values, while the accompanying lower and upper values describe the full range recorded for each arm.

Blood loss is a continuous outcome: it can take a range of measured values rather than only event/no-event categories. Comparing its distribution between relevant groups can help describe differences in blood loss associated with the study’s intervention question. In general, surgical blood loss is a clinically relevant perioperative measure, but a group summary alone does not establish that an intervention caused a difference. Interpretation also depends on the comparability of groups, the amount and variability of data, measurement methods, and the analysis used.

The record gives no transfusion result, despite mentioning transfusion rates in the study summary. It also gives no details about how blood loss was measured or whether the endpoint included a standardized measurement protocol. Those details are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean describe?

In general, a mean is a measure of the center of a set of observations, formed by balancing the observed values across the group. It can be useful for describing a continuous outcome such as blood loss, but it does not show how values are distributed around that center. The registry labels the blood-loss parameter as MEAN. It also labels the dispersion as Full Range and reports a lower and upper endpoint for each arm with data. These measures answer different descriptive questions: the mean indicates the reported central summary, while the range marks the observed extremes.

A mean can be influenced by unusually high or low observations. This is relevant to the soft tissue TXA results, whose reported range extends from 100.0 to 1800.0 mL. With only 3.0 participants in that arm, each observation can have considerable influence on the mean. The range alone cannot reveal whether values cluster near the mean, whether there is one particularly high observation, or how the observations are ordered. No individual-level values or standard deviation are reported in the registry record.

How should a range be distinguished from a confidence interval?

In general, a full range describes the smallest and largest observed values in a group. A confidence interval instead describes uncertainty around an estimate under a statistical model and analysis. It is not the span of the observed participant values. The registry reports full ranges for the blood-loss endpoint, but does not report confidence intervals. Therefore, the reported ranges should not be used as if they quantified the precision of the group means or the uncertainty in a between-group effect.

Why does the trial structure matter?

In general, randomization can support causal comparisons when treatment groups are appropriately formed, analyzed as intended, and measured consistently. The registry identifies the study as randomized, but gives no details about the randomization sequence, concealment, or analysis populations. In addition, the arms are stratified by tumor and surgical type. The empty bony-tumor TXA arm means that the posted outcome cannot support the planned-looking within-bony-type contrast. The soft tissue arms have data, but the record supplies descriptive summaries rather than an inferential comparison. Randomized status by itself does not turn unadjusted arm summaries into a reported treatment-effect estimate.

What can be inferred from the reported summaries?

The summaries describe the recorded blood-loss outcomes in the arms with data. They do not show the individual observations, the estimated difference between arms, or the uncertainty around such a difference. A numerical contrast could be calculated from the listed means, but a recalculated contrast would not be the sponsor’s analysis and would not resolve the limitations of the sparse data or missing bony TXA arm. No recalculated contrast is needed to interpret what the registry actually reports.

In general, over-dispersion means that observed variability is greater than a model assumes. When present, it can make standard errors too small and confidence intervals too narrow if the model does not account for it. The posted summaries do not allow assessment of over-dispersion or selection of an appropriate variance model. This is a general statistical consideration, not a finding about this trial.

What is reported about planning?

The registry describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says that the effect to detect is a stated fraction of the observed effect. Such calculations, when presented, are planning illustrations; they are not observed power and do not establish that the completed trial had adequate precision. The registry record does not report the trial’s own sample-size justification or design assumptions. The posted information does not supply a single comparison or an observed effect estimate for all four arms, so the planning description should not be mistaken for evidence of a definitive overall comparison.

More generally, a confidence interval would convey a range of estimates compatible with the data and the analysis assumptions, whereas a p-value would quantify how unusual data at least as extreme as those observed would be under a specified null model. Neither is reported for a blood-loss comparison in this record. Without an analysis estimate and its uncertainty, the inferential strength of the observed arm summaries cannot be assessed from the registry results.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome measure, perioperative blood loss, and no posted secondary outcomes. It reports no outcome analyses. It therefore does not present a set of inferential tests from which to assess whether multiplicity adjustments were used. The record does not report a multiplicity plan, a hierarchy of hypotheses, or any adjustment for testing multiple outcomes or comparisons.

There are four arms, distinguished by tumor type and TXA use, but the registry does not identify a single pooled comparison or provide an analysis for the within-type comparisons. The absence of a posted analysis means there is no reported multiplicity procedure to interpret. It would be inappropriate to infer either that multiplicity was addressed or that it was ignored in the trial’s underlying analysis; that information is not reported in the registry record.

The record reports a blood-loss result for three arms and no participants in the bony-tumor TXA arm. It does not explain whether the empty arm resulted from recruitment, eligibility, withdrawal, or another reason. It also does not describe missing-data handling, exclusions, imputation, or whether analyses followed intention-to-treat or another population definition. These aspects of the analysis populations are not reported in the registry record.

In general, missing outcomes and multiple comparisons can affect the interpretation of estimates and uncertainty. Here, the absence of an outcome value in one arm is a direct limitation on the available comparison, while the missing analysis details prevent assessment of how the trial handled participants and outcomes in its statistical analyses. No conclusions about the unreported procedures should be inferred.

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.

The posted safety figures report no serious adverse events, other adverse events, or deaths in the groups with participants at risk. For the bony-tumor group without TXA, the registry lists 3 participants at risk for both serious and other adverse events and records 0 affected in each category, with 0 deaths. For the soft tissue TXA group, it lists 3 at risk and 0 affected for each adverse-event category, with 0 deaths. For the soft tissue group without TXA, it lists 6 at risk and 0 affected for each category, with 0 deaths.

The bony-tumor TXA safety group has 0 at risk and 0 recorded events; this does not provide a safety observation for participants receiving TXA in that surgical group. The posted counts are descriptive and arise from small groups. In general, observing no recorded events in a group does not establish that an event cannot occur or precisely quantify its frequency. The registry does not report further detail on adverse-event definitions, collection procedures, severity beyond the serious/non-serious categories, or follow-up duration. No broader safety conclusion can be drawn from these counts alone.

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

The registry record documents a randomized, single-masked, parallel-group Phase 4 study with four arms organized by tumor type and TXA use. It reports perioperative blood-loss summaries for the bony-tumor group without TXA and both soft tissue groups. The results are descriptive: group means and full ranges are posted, but no statistical comparison, confidence interval, or hypothesis test is reported. The bony-tumor TXA arm has no participants recorded for the primary outcome.

These registry entries mean that the posted results do not provide a complete comparison of TXA against no TXA across both surgical settings. The two soft tissue arm summaries can be read as the recorded blood-loss descriptions for those groups, but not as a causal estimate of TXA’s effect. The groups are small, the observed values vary, and there is no analysis of uncertainty. A numerical difference between the reported means would not by itself show whether any contrast is compatible with chance variation, nor would it address possible imbalance or other design and measurement issues.

The results also do not answer the transfusion-rate question mentioned in the study summary, because the record posts no transfusion outcome. The absence of recorded adverse events in groups with participants at risk is likewise not proof of an absence of risk, particularly given the limited group sizes and missing safety-method details. The termination status is recorded, but the reason for termination is not reported.

In general, a small or incomplete dataset can be useful as a descriptive record while remaining insufficient for strong inferential conclusions. These results do not establish that TXA increases, decreases, or leaves unchanged perioperative blood loss or transfusion rates. They also do not establish equivalence between groups. The most defensible interpretation is limited to the recorded arm-level summaries and the explicit gaps in the registry record.

13. Why This Trial Matters Statistically

This trial illustrates a central issue in clinical statistics: the design label and the results available for interpretation are not the same thing. Randomization is a design feature, but a useful treatment comparison also requires data in the relevant groups, a clearly specified comparison, and an analysis that reports an estimate with its uncertainty. The bony-tumor TXA arm has no outcome participants recorded, and no comparison estimate is posted. Thus, the randomized designation does not by itself supply evidence about the treatment contrast.

The separate tumor groups also highlight the importance of defining the target question. Bony tumor resection with endoprosthetic reconstruction and lower-extremity soft tissue sarcoma resection are distinct surgical contexts in the registry descriptions. A single pooled result would need a rationale and analysis that respects those differences. Since no pooled or within-type inferential analysis is reported, readers should not assume the arm summaries answer one common treatment question.

The blood-loss results further show why precision matters. The registry reports means and full ranges, but no confidence intervals or individual observations. In general, variability and small groups can make estimates imprecise, and ranges cannot substitute for uncertainty intervals. Statistical interpretation depends not only on the apparent size of a group summary, but also on how much information supports it and how the analysis was conducted.

Finally, registered outcomes and posted results can differ in scope. The study summary mentions transfusion rates, yet the posted outcome is blood loss alone. Separating stated aims from reported outcomes prevents an unreported endpoint from being mistaken for evidence. This record is therefore useful for understanding what was registered and what results are available, while also showing why careful limits on interpretation are essential.

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 main outcome limitation is the absence of blood-loss data for the bony-tumor TXA group. As a result, the registry cannot support a reported TXA versus no-TXA comparison within that surgical setting. For soft tissue sarcoma, results are available in both TXA groups, but the record gives descriptive summaries only and no estimate of the between-group effect or its precision.

The reported groups are small, and the soft tissue TXA range is wide relative to its group summary. The record gives means and full ranges but no individual values or standard deviations, making it difficult to assess the shape of the outcome distribution or the influence of particular observations. It does not describe blood-loss measurement procedures, use of transfusion thresholds, or whether outcome measurement was standardized.

Several design and analysis details are also missing. The registry does not report the randomization method, who was masked, allocation concealment, the reason for termination, adherence, participant flow, analysis populations, missing-data procedures, or a statistical analysis plan. It mentions transfusion rates in the brief summary but posts no transfusion outcome. The record does not report follow-up details relevant to safety or further adverse-event definitions and collection methods.

These limitations are specific to the available record and should not be treated as proof that procedures were not performed. They mean those procedures cannot be evaluated from the registry information. Together, the empty bony TXA outcome arm, limited descriptive data, and absence of inferential results sharply restrict the conclusions that can be drawn about TXA and perioperative blood loss.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Tranexamic Acid in Radical Resection and Endoprosthetic Reconstruction — NCT04347122.
• Registry record last updated 2025-05-21; status last verified 2025-05.
• Results first posted 2025-05-21.
• 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

NCT04347122 is a randomized, single-masked, parallel-group Phase 4 trial sponsored by the University of Kansas Medical Center. It is listed as terminated, with a start date of 2020-01-28, a primary completion date of 2023-08-18, and enrollment of 12. The study concerns TXA use in bony tumor surgery with endoprosthetic reconstruction and in lower-extremity soft tissue sarcoma resection.

The primary outcome is perioperative blood loss in mL, with a stated timeframe of 4 to 6 hours. The registry reports means and full ranges in three arms; the bony-tumor TXA arm has no participants recorded for this outcome. No statistical analyses or secondary outcomes are posted. The record gives safety counts with no recorded adverse events in groups with participants at risk, but does not report further safety methods. It does not explain the termination or provide a transfusion result.