Sentinel Node Detection in Clinical Early Stage Ovarian Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Sentinel Node Detection in Clinical Early Stage Ovarian Cancer (NCT01734746), a na na study. The primary outcome is Number of Patients (%) in Which Sentinel Node(s) Are Detected After Injection of Blue Dye and Tracer in the Ovarian Ligaments..

2. Clinical Question

3. Trial Design

This completed study, NCT01734746, is titled “Sentinel Node Detection in Clinical Early Stage Ovarian Cancer.” Maastricht University Medical Center is listed as the sponsor. The registry gives a start date of 2012-10 and a primary completion date of 2014-10. Enrollment is listed as 22. The phase is recorded as NA.

The design is single-group, and allocation is listed as NA. Masking is listed as none. These entries describe a study without a randomized control arm; the record does not describe a comparison group. The intervention is a procedure, called tracer injection, using both blue dye and a radioactive technetium-99-m-labeled albumin nanocolloid. The registry description places the injections in two ovarian ligaments, close to the ovary and just below the peritoneum.

The stated purpose was to determine whether a sentinel node procedure was feasible when tracers were injected in the ovarian ligaments. The primary endpoint concerns detection during surgery. An additional outcome concerns the anatomical locations of sentinel nodes. The record lists three outcome measures, but does not provide details for all of them in the information available for this analysis.

The single-group design is suited to describing whether detection occurred among participants who underwent the procedure. Without a comparator, it cannot by itself establish whether detection is more frequent than under another approach. Nor does detection alone establish diagnostic accuracy: that would require information connecting sentinel node findings with the status of other nodes or another reference standard. Such results are not reported in the registry record.

Although the registry marks the study completed, completion status does not supply the missing outcome estimate. The record does not report a primary endpoint count, percentage, confidence interval, or analysis population. Therefore, the study’s actual observed detection result cannot be assessed from the registry information.

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

Analysis population for the primary outcome, as defined in the registry: see Kleppe et al., J Nucl Med 2014; 55:1799-1804

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 Patients (%) in Which Sentinel Node(s) Are Detected After Injection of Blue Dye and Tracer in the Ovarian Ligaments., measured over During surgery..

The primary endpoint is the number and percentage of participants in whom sentinel node or nodes were detected after blue dye and tracer were injected into the ovarian ligaments. The registry specifies that the assessment took place during surgery. It is a binary participant-level outcome for analysis: a participant either had sentinel node detection recorded or did not. The endpoint title refers to the number of participants and the percentage, but the corresponding result is not reported in the registry record.

Detection is relevant to the stated feasibility question because the procedure depends on locating a sentinel node after tracer injection. An endpoint based on detection can describe whether the technique produces a localizable node in the operative setting. It does not, by itself, establish whether the detected node accurately represents the status of other lymph nodes, whether cancer is present in a detected node, or whether using the procedure changes patient outcomes. Those are different questions and require other outcome information.

The registry also lists anatomical location of sentinel nodes as a secondary outcome. Location can describe where detected nodes were found, but it is not a substitute for the primary detection count. Neither the primary endpoint value nor the anatomical-location results are reported in the registry record. The enrollment figure is not an endpoint denominator: the number of participants with an evaluable primary outcome is not reported.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a single-group study with a binary primary outcome: sentinel node detection during surgery. The outcome is expressed in the endpoint title as a number of participants and a percentage. The record does not report the observed event count, analysis denominator, percentage, or statistical analysis method. The explanations below describe general statistical principles for this type of outcome; they do not imply that a particular method was used in this study.

What does a participant-level detection outcome represent?

For a binary outcome, each participant contributes an outcome category, such as detection recorded or detection not recorded. The event count is the number in the category of interest, and the denominator is the number with outcome data included in the analysis. A percentage expresses that count relative to that denominator. The denominator should not automatically be assumed to equal enrollment: participants may lack an assessable outcome, and the registry does not state the primary analysis denominator.

For a feasibility question, the observed proportion can describe how often the procedure led to node detection in the analyzed participants. It is a descriptive estimate for the study setting and participants. It is not, on its own, a comparison with another procedure or a direct measure of diagnostic accuracy. The study’s single-group design has no listed control arm from which to estimate a relative difference.

Why is uncertainty relevant?

A proportion from a study is an estimate, not a guarantee that the same proportion would be observed in another sample. A confidence interval is a general statistical way to express the uncertainty around an estimate, under the assumptions of the method used. Its width depends in part on how much outcome information is available and on the pattern of observed outcomes. An interval would help readers judge the range of values compatible with the data and method. No confidence interval is reported for this endpoint in the registry record.

Different interval procedures can behave differently, especially when outcome counts are small or close to a boundary. The registry record does not report which interval method, if any, was used. It would therefore be inappropriate to attribute a particular method or precision to the study. A point estimate without its denominator and uncertainty would also be difficult to interpret; neither is reported in the registry record.

What can a single-group design estimate?

A single-group design can estimate the frequency of an outcome among participants who undergo the procedure, assuming outcome ascertainment and analysis are adequately described. It cannot separate the procedure’s effect from other influences using a concurrent group comparison, because no comparator is listed. This is especially important when interpreting a feasibility endpoint: the proportion detected describes the experience in the study, but does not show how detection would differ under another approach.

Detection also differs conceptually from diagnostic performance. Locating a sentinel node establishes that a node was detected; it does not establish whether the node correctly reflects cancer status elsewhere. To assess diagnostic performance, information about node pathology and an appropriate reference assessment would be needed. These results are not reported in the registry record.

How should the planning assumptions be read?

The registry describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also states that the effect to detect is a stated fraction of the observed effect. These are assumptions for a planning illustration, not evidence that the completed study used two randomized arms. The trial itself is recorded as single-group, with allocation listed as NA.

A sample-size calculation is a planning exercise: it asks how much information might be needed under specified assumptions. It is not an observed study result and is not “observed power.” The registry does not report the calculated planning values in the information available for this analysis, and the primary outcome estimate needed to understand an observed-effect-based illustration is also not reported. Thus the planning assumptions cannot be used to recover the missing endpoint result or establish that the study was adequately sized.

What analyses are documented?

The registry lists zero analyses. It does not report a statistical analysis plan, a model, an adjustment strategy, an interim analysis, a hypothesis test, or an interval estimate for the primary endpoint. The absence of these details does not show what the investigators did outside the registry; it means those methods are not reported in the registry record. The endpoint and design support a straightforward descriptive question, but the actual calculation and handling of incomplete observations cannot be verified from the record.

General statistical practice would report the event count, the analysis denominator, the resulting proportion, and an uncertainty interval, alongside a clear account of missing outcomes. If the purpose is feasibility, interpretation should remain focused on detection and avoid claims about comparative benefit or accuracy unless those questions are directly assessed. In this study, the registry information does not include the data needed to make even the primary descriptive assessment.

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("Sentinel Node Procedure")
n      <- c(21)
events <- c(21)
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  Sentinel Node Procedure  21  21  100.0  83.9  100.0  84.5  100.0  84.6  99.9

11. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures and names anatomical location of sentinel nodes as a secondary outcome. It does not give the full outcome details or results for all measures in the record available for this analysis. Nor does it report a multiplicity strategy, such as whether any adjustment was planned for considering multiple outcomes or analyses. The record lists zero analyses, so it does not provide a set of reported tests from which to assess multiplicity in practice.

Multiplicity is a general concern when several outcomes or statistical tests are considered: the chance of at least one apparently notable result can change as the number and selection of analyses change. How to address that concern depends on the study questions and analysis plan. No such plan is reported in the registry record, so no claim can be made about whether multiplicity was controlled or how outcomes were prioritized beyond the designation of the primary endpoint.

The registry does not report the number of participants with complete primary endpoint data, the number with missing outcomes, or how missing observations were handled. Enrollment of 22 should not be treated as the primary analysis denominator without that information. The record also does not describe an analysis population, such as whether all enrolled participants or only those who underwent the procedure and had an evaluable endpoint were included. These details are necessary to judge whether the reported analysis, if available, represents the enrolled group or a subset.

Because the primary outcome value and its denominator are not reported, the effects of missing data cannot be assessed. The registry also does not report an imputation method, sensitivity analysis, or reasons for missing outcome information. These are not evidence that missing data occurred; they are aspects that are not reported in the registry record. No conclusion about completeness or potential bias from missing outcomes can be drawn.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

For the group titled “Sentinel Node Procedure,” the registry lists 21 participants at risk for serious adverse events and 0 affected. It also lists 21 at risk for other adverse events and 0 affected. These are the safety figures recorded for the intervention group. Deaths are not reported in the registry record.

A recorded count of 0 affected means that no affected participants are listed for those categories in the registry entry. It should not be read as proof that the procedure carries no risk. Safety counts are descriptive and depend on which events were collected, how they were defined, the observation period, and which participants contributed safety information. Those details are not reported in the registry record. The safety group’s at-risk count is not a replacement for the missing primary endpoint denominator.

These figures do not permit a comparison with another procedure because no comparator group is listed. Nor do the registry figures, on their own, establish that no adverse events occurred outside the recorded categories or reporting period. They should be interpreted narrowly as the serious and other adverse-event counts entered for the stated group, with deaths not reported.

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

The study addresses whether sentinel nodes can be detected during surgery after blue dye and tracer are injected into ovarian ligaments. Its single-group design and stated primary endpoint make it a feasibility-focused study: the central descriptive quantity would be the fraction of analyzed participants with node detection. However, that outcome count and percentage are not reported in the registry record. As a result, the posted information does not show the detection result or its precision.

Even if a detection proportion were available, its meaning would be specific. It would describe observed localization in the study participants and setting. It would not, by itself, establish that a detected node predicts the status of other lymph nodes, that cancer can be ruled out when a sentinel node is negative, or that the procedure improves outcomes. Those conclusions require other evidence and outcomes not reported in the registry record.

The design also does not support a comparative claim. A single group cannot show whether the procedure performs better or worse than another approach in the absence of a comparator. The registry lists no allocation to competing arms and no control group. The trial’s completion status and enrollment figure do not fill that gap or substitute for the endpoint result.

The safety entry records 0 affected for serious adverse events and 0 affected for other adverse events among the stated at-risk group. These counts should be treated as registry-reported observations, not as proof of no risk. The record does not report deaths, detailed event definitions, or safety follow-up information.

Overall, the registry establishes the study question, intervention, design, and some safety counts. It does not provide the primary result necessary to answer whether sentinel nodes were detected, nor the information required to assess diagnostic accuracy or comparative performance. A measured feasibility result should not be inferred from the study’s title, stated objective, or completion status.

14. Why This Trial Matters Statistically

This trial is statistically useful to consider because it separates a feasibility question from comparative effectiveness and diagnostic accuracy. The study asks whether a node can be located during surgery after tracer injection. That is a measurable technical outcome, but it answers a narrower question than whether a sentinel node reliably represents the status of other nodes or whether a procedure changes clinical outcomes.

The single-group structure also makes the scope of inference clear. A proportion of participants with detected nodes, if reported, would describe the observed experience under the study procedure. Without a comparator, it would not estimate how detection differs from another technique. This distinction helps prevent a descriptive feasibility result from being interpreted as a treatment effect.

The record’s missing primary outcome illustrates why endpoint counts, denominators, and uncertainty estimates matter. Enrollment alone does not show how many participants had evaluable outcome data. Without the detection count and analysis denominator, readers cannot judge the observed rate or how precisely it is estimated. A completed status does not make those missing statistical details inferable.

The planning assumptions further highlight the importance of matching statistical interpretation to design. A two-arm, equal-allocation planning illustration is described, while the registered study is single-group. Planning assumptions are not a description of the trial’s observed design, and a sample-size illustration cannot replace the missing outcome data. The record does not provide the calculated planning values or an analysis plan.

Finally, the safety counts are limited descriptive information rather than a comparative safety assessment. The study’s value for statistical interpretation lies in recognizing what its design and recorded outcomes could address, and what cannot be concluded without results and methods that are not reported in the registry record.

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 main limitation for interpreting this trial from the registry is that the primary endpoint result is not reported. Although the outcome is defined as the number and percentage of participants with sentinel node detection during surgery, the registry record does not give the count, percentage, analysis denominator, or an interval describing uncertainty. The listed enrollment of 22 cannot be assumed to be the endpoint denominator.

The single-group design has no comparator, so it cannot support a direct comparison with another injection method, another surgical approach, or no tracer procedure. This limits causal and comparative conclusions even if the primary result were available. The study’s detection endpoint also does not establish diagnostic accuracy or clinical consequences. The registry does not report results linking detected nodes with other lymph node findings or a reference standard.

Additional methods details are not reported in the registry record. These include the primary analysis population, handling of missing outcomes, a statistical analysis plan, the method for calculating uncertainty, and whether any interim analyses were conducted. The record lists zero analyses, and therefore does not permit assessment of model choices or adjustment for other factors. Three outcome measures are listed, but a multiplicity strategy is not reported.

The safety entry records counts for serious and other adverse events, but event definitions, collection procedures, and safety follow-up details are not reported. Deaths are not reported in the registry record. These limits do not establish that any particular methodological problem occurred; they identify information unavailable for interpretation.

Finally, the record’s planning assumptions describe a two-arm illustration despite the trial’s single-group design. That illustration should not be taken as the study’s actual design or as evidence about the observed result. Its calculated values are not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Sentinel Node Detection in Clinical Early Stage Ovarian Cancer — NCT01734746.
• Registry record last updated 2018-11-05; status last verified 2018-04.
• Results first posted 2018-11-05.
• 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

NCT01734746 is a completed, single-group study sponsored by Maastricht University Medical Center, titled “Sentinel Node Detection in Clinical Early Stage Ovarian Cancer.” The registry lists enrollment of 22, no masking, and phase NA. The intervention was tracer injection using blue dye and technetium-99-m-labeled albumin nanocolloid in the ovarian ligaments.

The primary question concerned the number and percentage of participants with sentinel node detection during surgery. Anatomical location of sentinel nodes is listed as a secondary outcome. The primary outcome result, its analysis denominator, and statistical uncertainty are not reported in the registry record. The record lists zero analyses.

For the Sentinel Node Procedure group, 21 participants are listed at risk for serious adverse events and 0 affected; for other adverse events, 21 are listed at risk and 0 affected. Deaths are not reported. The registry describes planning assumptions for an illustration, but those assumptions do not change the study’s single-group design or provide the missing outcome result.