Concurrent Use Lymphoseek & Indocyanine Green in Sentinel Lymph Node Detection in Endometrial Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Concurrent Use Lymphoseek & Indocyanine Green in Sentinel Lymph Node Detection in Endometrial Cancer (NCT04511026), a na phase 2 study. The primary outcome is Number of Participants With Bilateral SLNs.

2. Clinical Question

In statistical terms, the central question is descriptive: among participants treated under this study’s single-group approach, how many had bilateral SLNs detected under the registry’s definition? That is different from asking whether concurrent use improves detection compared with a control approach. Without a comparison group, a difference in detection attributable to the combined approach cannot be estimated from this design alone.

3. Trial Design

The registry identifies this as a prospective phase 2 study sponsored by Stanford University. It lists a single-group model, allocation as not applicable, and no masking. Enrollment was 6. The study began on 2021-01-20, had a primary completion date of 2021-06-10, and is listed as terminated. The reason for termination is not reported in the registry record.

The single listed group is named Lymphoseek/SPECT-CT/Indocyanine. According to the arm description, Lymphoseek was to be injected into the uterine cervix before surgery, followed by preoperative SPECT/CT imaging. ICG was to be injected into the cervix intraoperatively following anesthesia induction. The intervention list also includes the Neoprobe Gamma Detection System and SPECT. The arm description in the registry record is incomplete, so additional procedural details should not be inferred from it.

The primary outcome was recorded as a participant count: participants with bilateral SLNs detected during surgery, with a timeframe described as during surgery, an average of 3 hours. The registry also lists secondary outcomes concerning overall SLN detection and the number and location of SLNs detected by Lymphoseek and by ICG. These outcome descriptions indicate what the study intended to assess, but they do not supply numerical results.

There is no parallel control group or randomized allocation described. Consequently, the design can describe detection under the combined approach but cannot by itself separate the contributions of Lymphoseek, ICG, imaging, and gamma detection. The registry record does not report a protocol-level statistical analysis plan, sample-size justification, or reason for the study’s termination.

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

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 Number of Participants With Bilateral SLNs, measured over during surgery, an average of 3 hours.

The primary endpoint is the number of participants with bilateral sentinel lymph nodes detected during surgery. It is a participant-level count: a participant is counted according to whether the study’s detection criteria identify bilateral SLNs, rather than according to the total number of nodes found. The registry defines an SLN as detected if identified on preoperative SPECT/CT imaging or intraoperatively using near-infrared imaging or the handheld gamma detection device.

This endpoint is relevant to the stated study aim because detection on both sides addresses whether bilateral sentinel-node mapping was achieved under the study approach. It also gives a concrete summary of detection during the surgical episode. The registry specifies an average timeframe of 3 hours during surgery, so this is an operative detection outcome rather than a long-term clinical outcome.

The endpoint’s interpretation depends on the recorded definition: a node detected by any of the listed modalities qualifies. It therefore does not measure the independent performance of each modality on its own. The registry record does not provide the observed participant count for this primary outcome, nor does it report a confidence interval or an analysis result. The endpoint’s numerical result is therefore not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a count of participants who meet a binary criterion: having bilateral SLNs detected under the study definition. A binary outcome records whether a participant meets a specified condition. Here, the participant is the unit for the primary count; the endpoint is not simply the number of individual nodes detected. The record defines detection using preoperative SPECT/CT or intraoperative near-infrared imaging or a handheld gamma detection device.

What does the endpoint count?

A participant-level count can be reported directly as the number meeting the criterion. An analysis may also express such a count relative to the number of participants assessed, but no primary outcome result or denominator for the analyzed population is reported in the registry record. No proportion should therefore be inferred from the enrollment figure alone. Enrollment describes the study’s listed enrollment, not necessarily the number with an observed primary outcome.

For a binary outcome, a confidence interval is a range of values compatible with the data under the method used. Its width conveys uncertainty: a wider interval indicates less precision, while a narrower interval indicates greater precision. The registry record does not report a confidence interval for bilateral detection. Without the outcome count and analysis details, its precision cannot be assessed from the record.

What can a single-group estimate say?

A single-group analysis can describe the outcome in the group observed. It cannot, by itself, distinguish the effect of the study approach from other explanations for the observed outcome or establish how the outcome would differ under a separate treatment or detection strategy. This is especially relevant because the study’s detection definition accepts findings from multiple modalities, while the interventions are used concurrently. A group-level detection result would not independently estimate the contribution of each modality.

Comparative tests and effect estimates require a meaningful comparison structure and reported data. This record lists no control arm and no randomized allocation. The registry also lists no analyses. It is therefore not possible to interpret a treatment contrast, a test of between-group difference, or an adjusted analysis from the information recorded.

What do the planning assumptions mean?

The registry describes planning illustrations using a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It also states that the effect to detect is a specified fraction of the observed effect. These are described as planning assumptions, not as the trial’s own design. They do not match the listed single-group design, and they should not be read as evidence that this study randomized participants or had two study arms.

Such sample-size calculations are planning scenarios: they explore how many participants per arm for 80% power might be needed under stated assumptions. They are not observed power, do not establish that the study was adequately powered, and do not substitute for the actual outcome result. The registry record does not report the numerical observed effect used for those illustrations, so the assumptions cannot be independently interpreted alongside an observed primary result from this record.

More generally, power is a design-stage probability tied to a specific outcome, effect size, significance level, and analysis. It is not a measure of whether a result is true, nor a retrospective score for a completed study. A small or imprecise study may fail to distinguish an effect from chance even when a potentially meaningful difference exists; conversely, a statistically detectable result does not alone establish practical importance. These general principles cannot recover the missing trial outcome.

How should the safety counts be interpreted?

Safety counts are descriptive event summaries. The registry reports serious adverse events, other adverse events, and deaths for the listed group. A count of 0 means no event of that category was recorded among participants at risk in the registry entry. It does not establish that the underlying event probability is zero. The record does not provide comparative safety estimates, event-level descriptions, or an inferential analysis.

In general, uncertainty around an event rate depends on both the observed event count and the number of people assessed, as well as the chosen statistical method. When the recorded event count is zero, that does not eliminate uncertainty about events that could occur in a broader population. No interval estimate is reported, and none should be reconstructed without the relevant outcome details and analysis method.

The registry’s analysis count is 0. This means no analysis is listed in the record; it does not clarify whether investigators performed analyses that were not entered into the registry. The statistical analysis plan, handling of missing data, and analysis populations are not reported in the registry record. Interpretation should therefore remain limited to the design descriptions and the outcome and safety counts that are actually recorded.

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("Lymphoseek/SPECT-CT/Indocyanine")
n      <- c(6)
events <- c(6)
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  Lymphoseek/SPECT-CT/Indocyanine  6  6  100.0  54.1  100.0  61.0  100.0  59.0  99.6

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome concerning participants with bilateral SLNs and secondary outcomes concerning overall SLN detection and the number and location of nodes detected by Lymphoseek and ICG. Assessing several outcomes can raise a multiplicity question: if many statistical tests are conducted, the chance of at least one apparently unusual result may increase. Whether that issue was relevant depends on the planned analyses and how the outcomes were treated.

A multiplicity strategy—such as designating a hierarchy of outcomes or adjusting significance thresholds—is not reported in the registry record. The record lists no analyses, so it does not establish which outcomes were tested, whether tests were performed, or whether any adjustment was used. The presence of several outcome descriptions alone is not evidence that formal hypothesis tests were conducted.

Missing-data methods are also not reported in the registry record. There is no description of how participants without an evaluable detection outcome would be handled, whether missing observations occurred, or whether any imputation was planned. Enrollment cannot be treated as the analyzed population without an explicit report of who contributed data to each outcome.

The registry record does not report analysis populations, such as an intention-to-treat population or a per-protocol population. It also does not report exclusions, deviations from the planned procedure, or outcome-specific denominators. These details matter because the number analyzed may differ from enrollment, and different analysis populations can answer different questions.

These omissions do not demonstrate that missing data or multiplicity problems occurred. They mean the record does not allow readers to determine how those issues were addressed. The numerical primary and secondary outcome results are not reported in the registry record, limiting interpretation further.

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 0% reporting threshold.

The registry lists 0 serious adverse events among 6 participants at risk in the Lymphoseek/SPECT-CT/Indocyanine group. It also lists 0 other adverse events among 6 at risk and 0 deaths. No serious adverse event terms are listed.

These are recorded counts, not evidence that the risk of an adverse event is absent. A zero count means that no event in the specified category was recorded for the participants at risk in this entry. It does not determine what might occur in a larger population, and the registry provides no comparative group for estimating relative safety.

The record does not give event narratives, severity details beyond the serious-event category, or an analysis of safety outcomes. The listed counts should therefore be interpreted narrowly as registry-recorded observations. They do not establish that the study approach is safe or unsafe, and they do not explain why the study was terminated.

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

The study record describes an investigation of concurrent Lymphoseek and ICG use for sentinel lymph node detection in endometrial cancer. It specifies a participant-level primary outcome—participants with bilateral SLNs detected—and defines which imaging or detection modalities could qualify a node as detected. This provides a clear description of the intended measurement.

However, the numerical primary outcome is not reported in the registry record. The record therefore does not show how many participants had bilateral detection or how precisely that result was estimated. It also does not give numerical results for the listed secondary detection outcomes. No conclusion about the observed detection result can be drawn from the outcome definitions alone.

The study’s single-group structure is important for interpretation. Even if a within-group detection result were available, it would describe outcomes under the combined approach rather than establish a comparative benefit over another method. Because the definition allows detection by multiple modalities, a group-level result would not identify the independent effect of Lymphoseek, ICG, SPECT/CT, or gamma detection.

The record’s safety counts are 0 serious adverse events, 0 other adverse events, and 0 deaths in the listed group. Those counts describe what the registry records for this study; they do not show that adverse events are impossible or provide a comparison with another approach. The reason for the terminated status is not reported.

Accordingly, this record supports a description of the research question, study structure, outcome definition, and listed adverse-event counts. It does not support a claim that the combined approach does or does not improve detection, reduce additional surgical dissection, or change safety relative to another strategy. Those conclusions require reported outcome data and, for comparative claims, an appropriate comparison.

14. Why This Trial Matters Statistically

This study poses a practical measurement question: whether bilateral sentinel lymph nodes can be detected when Lymphoseek and ICG are used in the same surgical pathway. Statistically, the question highlights the difference between defining an outcome and reporting its observed value. The registry gives a detection definition and a primary endpoint, but does not report the primary result. Without that result, the central descriptive quantity cannot be evaluated.

The design also illustrates why the comparison structure matters. A single-group study can document outcomes under a procedure, but cannot by itself estimate how those outcomes differ from a separate approach. This limitation is especially relevant when several detection modalities contribute to the endpoint. A combined detection result does not establish which modality identified a node or what would have happened under another protocol.

The enrollment of 6 and the absence of a reported primary outcome make precision impossible to assess from the registry record. A small study can be useful for describing feasibility or informing later research, but conclusions depend on the results actually reported and the design’s ability to address its question. The registry does not report a sample-size justification or a statistical analysis plan that would clarify the intended inferential scope.

The listed safety counts also demonstrate a basic interpretive point: zero recorded events are observations, not proof of zero underlying risk. Without comparative data and fuller event reporting, those counts cannot establish a safety difference.

For readers evaluating clinical research, the key statistical lesson is to separate the study’s goal, its endpoint definition, its design, and its reported results. Here, the goals and definitions are recorded, but the numerical detection results and analysis details are not. That boundary determines what can responsibly be concluded from this registry entry.

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 registry record lists enrollment of 6 and a single-group design. It has no separate control group and no randomized allocation. This limits comparative interpretation and makes it impossible to distinguish the effects of the combined detection approach from the contributions of its individual components using a between-group contrast.

The primary outcome result is not reported in the registry record. Numerical results for the secondary detection outcomes are also not reported. The record therefore does not permit assessment of the observed detection frequency, its uncertainty, or the relation between different detection modalities.

The primary endpoint definition counts detection established through preoperative SPECT/CT or intraoperative near-infrared imaging or the handheld gamma detection device. This combined definition is aligned with an overall detection question, but it does not isolate modality-specific performance. Although secondary outcomes are listed for node numbers and locations by tracer, their results are not reported.

The record lists the study as terminated, without reporting the reason. It does not provide a statistical analysis plan, sample-size justification, interim-analysis information, missing-data methods, or analysis populations. It also does not report outcome-specific denominators or explain whether all enrolled participants contributed to each measure. These gaps make it difficult to assess possible selection, missingness, or departures from planned procedures.

The arm description is incomplete, leaving some procedural detail unavailable in the registry record. The safety information is limited to the listed counts and does not include event narratives or a comparative assessment. Together, these limitations mean the entry describes the study’s intent and broad design more fully than its results or analytic conduct.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Concurrent Use Lymphoseek & Indocyanine Green in Sentinel Lymph Node Detection in Endometrial Cancer — NCT04511026.
• Registry record last updated 2023-10-11; status last verified 2023-09.
• Results first posted 2023-10-11.
• 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

NCT04511026 is a prospective phase 2 study sponsored by Stanford University on concurrent Lymphoseek and ICG use for sentinel lymph node detection in endometrial cancer. It is listed as a single-group study with no masking, enrollment of 6, and terminated status. The registry gives a start date of 2021-01-20 and a primary completion date of 2021-06-10.

The primary outcome is the number of participants with bilateral SLNs detected during surgery, using a definition that accepts detection by the listed imaging or intraoperative modalities. The numerical primary outcome and secondary detection results are not reported in the registry record. The record lists 0 serious adverse events, 0 other adverse events, and 0 deaths in the study group. It does not report the reason for termination, an analysis plan, or analysis populations.