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 Hysteroscopic Lymphatic Mapping for Endometrial Cancer (NCT00671606), a na phase 2 study. The primary outcome is Sentinel Node Identification Rate.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00671606 |
| Phase | Phase 2 |
| Condition | Endometrial Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 5 |
| Arms in the primary outcome | n/a |
| Lead sponsor | M.D. Anderson Cancer Center |
| Results posted | Yes |
2. Clinical Question
Population
Women with endometrial cancer were the intended population. The registry record lists endometrial cancer as the condition and reports enrollment of 5 participants.
Intervention
The procedure was intraoperative lymphatic mapping, using hysteroscopic injection of patent blue dye and radiocolloid. A gamma counter was used to look for lymph nodes that had absorbed Tc-99m sulfur colloid.
Comparator
There was no comparator group. The study is listed as a single-group study, and allocation is recorded as NA. The design therefore does not provide a like-for-like control comparison.
Primary question
The primary question was whether sentinel nodes could be identified using intraoperative hysteroscopic tracer injection in patients with endometrial cancer. The primary endpoint was the sentinel node identification rate. The registry record says feasibility was assessed with a planned enrollment of 20 participants, approximately 1 year, but lists actual enrollment of 5 and says no analysis was conducted due to low detection rate.
This is a feasibility question about whether the procedure can identify sentinel nodes, not a comparative question about outcomes under different treatments. The registry record describes identification before and during surgery as part of a procedure performed prior to or during routine surgery. It does not report an identification count, rate, uncertainty interval, or analysis result. Consequently, the central question is recognizable, but its result cannot be quantified from the registry record.
3. Trial Design
The registry record identifies NCT00671606 as a phase 2 study titled “Hysteroscopic Lymphatic Mapping for Endometrial Cancer.” Its official title describes hysteroscopic injection of tracers for sentinel node identification in women with endometrial cancer. M.D. Anderson Cancer Center is listed as the sponsor. The listed start is 2008-04, the primary completion is 2010-06, and the status is terminated.
The study is classified as a single-group design, with allocation recorded as NA and masking recorded as none. The only listed intervention is intraoperative lymphatic mapping, categorized as a procedure. No control arm is listed. These design features matter because the study can describe experience with the procedure but cannot establish a comparative treatment effect against a control group.
Enrollment is listed as 5. The primary outcome description says feasibility was assessed with enrollment of 20 participants, approximately 1 year. These entries describe different aspects of the record: the stated feasibility assessment and the actual enrollment recorded. The registry record does not explain why enrollment was lower than the stated assessment target or why the study was terminated.
The primary outcome was sentinel node identification rate, with a timeframe described as a 15-20 minute procedure prior to or during routine surgery for identifying sentinel nodes. The record describes using patent blue dye and radiocolloid, and a gamma counter to identify nodes that absorbed Tc-99m sulfur colloid. The listed analysis population is per protocol, but the record states that no analysis was conducted due to low detection rate. Thus, the design and intended endpoint are described, while a numerical primary result is 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 | Intraoperative Lymphatic Mapping |
|---|---|
| STARTED | 5 |
| COMPLETED | 5 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Analysis was per protocol; no analysis conducted due to low detection rate.
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 | Intraoperative Lymphatic Mapping |
|---|---|---|
| Participants analysed | 5 | |
| Age, Continuous | years | 56 (49 to 65) |
| Sex: Female, Male: Female | Participants | 5 |
| Sex: Female, Male: Male | Participants | 0 |
| Region of Enrollment: United States | participants | 5 |
6. Primary Endpoint
The registry lists the primary outcome as Sentinel Node Identification Rate, measured over 15-20 minute procedure prior to/during routine surgery for identifying the sentinel nodes.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint, sentinel node identification rate, is intended to describe how often the mapping procedure identifies a sentinel node. For a feasibility study, that outcome addresses whether the procedure can produce the target identification, rather than whether it improves a later clinical outcome. The registry record describes hysteroscopic injection of patent blue dye and radiocolloid, followed by identification before and during surgery using a gamma counter to locate nodes that absorbed Tc-99m sulfur colloid.
As a general statistical concept, a rate represents the number of participants or procedures meeting an outcome divided by the relevant number assessed. Its interpretation depends on a clear definition of what counts as successful identification and which participants are included. The registry record gives the endpoint name and procedure description, but does not report the number of successful identifications, the number assessed for this outcome, or a calculated rate. It also does not state a more detailed operational definition of a successful identification.
The endpoint is useful for the stated feasibility question because it focuses on whether sentinel nodes can be located using the specified mapping approach. It does not, by itself, answer comparative questions about another mapping technique, diagnostic accuracy, subsequent treatment decisions, or patient outcomes. No such results are reported in the registry record. The recorded statement that no analysis was conducted due to low detection rate is not accompanied by an endpoint value or further detail, so it cannot be translated into a numerical estimate of feasibility.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted results do not include a numerical sentinel node identification rate. The registry record identifies that outcome as primary, describes the procedure, and states that no analysis was conducted due to low detection rate. The phrase “low detection rate” gives qualitative context, but no count, denominator, rate, or measure of uncertainty is reported. The magnitude and precision of the result therefore cannot be assessed from the registry record.
The study enrolled 5 participants, whereas the primary outcome description refers to feasibility assessment with enrollment of 20 participants, approximately 1 year. This enrollment context is important when reading the record: the listed study experience is limited, and the record does not provide the planned feasibility analysis or a numerical result. It does not explain the reason for the difference between the stated assessment enrollment and actual enrollment.
The design was single-group, with no control group and no masking. Accordingly, even a reported identification rate would describe the observed experience with this procedure in the enrolled study population; it would not provide a randomized or controlled estimate of how the procedure compares with another approach. The registry record does not report an analysis that could address comparative performance.
Precision is also unknown. In general, a confidence interval expresses a range of values compatible with the observed data under a statistical method, and helps readers distinguish a stable estimate from one that is uncertain. No confidence interval or other precision measure for sentinel node identification is reported in the registry record. Without the outcome count and denominator, even an unadjusted rate cannot be reconstructed.
The record labels the analysis population as per protocol, but also says no analysis was conducted due to low detection rate. It does not describe which participants met any per-protocol criteria or how the endpoint was handled for participants without an evaluable result. Thus, the analysis-population label does not supply an analyzed denominator or resolve the absence of a primary result.
These observations should not be read as evidence for or against the procedure’s performance beyond what is explicitly recorded. The registry record documents a feasibility objective, enrollment of 5, and a qualitative statement about low detection, but not a numerical outcome estimate. No statistical test result, uncertainty interval, or comparative analysis is reported. The defensible interpretation is therefore limited to the design, enrollment, and stated reason no analysis was conducted; stronger quantitative conclusions cannot be drawn from the posted results.
9. Statistical Methods Explained
Statistical interpretation begins with the question the study was designed to address. This study asked whether intraoperative hysteroscopic tracer injection could identify sentinel nodes in women with endometrial cancer. Its primary endpoint was the sentinel node identification rate. The registry record describes the procedure and the intended endpoint, but reports no numerical endpoint result and says that no analysis was conducted due to low detection rate.
What does a single-group design estimate?
In general, a single-group study describes outcomes observed among participants receiving the intervention under study. For a binary endpoint such as successful identification, the basic descriptive estimate is the proportion with the outcome among those assessed. The denominator must be defined: it could depend on enrollment, receipt of the procedure, adherence to a protocol, or availability of an evaluable outcome. A well-interpreted estimate therefore needs both a clearly defined outcome count and a stated denominator.
Here, the registry record lists a single-group design and no comparator. It does not provide an identification count, an analyzed denominator, or an estimated rate. The rate cannot be recalculated from the enrollment figure alone because enrollment does not reveal how many participants had an evaluable outcome or how many met the endpoint. The record’s qualitative statement about low detection does not fill in those missing quantities.
Why does precision matter?
As a general concept, a point estimate is an estimate derived from the observed data, while a confidence interval conveys uncertainty around that estimate under a specified statistical model. In small studies, estimates of proportions can be imprecise, especially when outcomes are uncommon or absent. The width and interpretation of an interval depend on the observed count, denominator, and interval method. Since the registry record reports neither a numerical rate nor its underlying counts, no interval for identification can be interpreted or reconstructed.
Precision and statistical significance are not interchangeable. A confidence interval describes uncertainty in an estimate; a hypothesis test evaluates data against a specified null hypothesis using a chosen procedure. The registry record does not report a test, a p-value, or an analysis plan for the primary endpoint. No claim about statistical significance can be made from the information recorded.
What can the design say about comparison?
A control group can help distinguish outcomes associated with an intervention from outcomes that might also occur under another approach or usual care. This study has no listed comparator and is not randomized. Its design can provide descriptive information about the mapping procedure, but it cannot estimate a comparative effect against an unobserved control condition. General explanations of comparison do not imply that such an analysis was planned or performed in this study.
Even if a single-group identification rate were available, it would not alone establish diagnostic accuracy. Accuracy questions require a specified reference standard and information about the relationship between the test result and that reference. The registry record does not report such an analysis. It also does not provide comparative results for another mapping method.
How should the per-protocol label be read?
The registry record labels the primary outcome population as per protocol, a term generally used for participants who satisfy specified study requirements. That label does not identify the actual analysis set unless the requirements and participant-level disposition are described. The record states that no analysis was conducted due to low detection rate, and it does not state how many participants met the per-protocol criteria or had an evaluable outcome. As a result, the label cannot be used to infer an endpoint denominator.
In general, analysis populations can affect interpretation when participants are excluded or outcomes are unavailable. Reasons for exclusion, protocol adherence, and missing outcome handling can influence which observations contribute to an estimate. The registry record does not provide participant-level information or a missing-data method for the primary endpoint. These details are not reported in the registry record, so no additional analysis population can be reconstructed.
What is not established by a feasibility endpoint?
A feasibility endpoint is designed to describe whether a procedure can be carried out or whether a targeted process outcome occurs. It should not be treated as a substitute for later clinical outcomes or a comparative evaluation. The identification rate, if reported, would answer a procedural question under the study conditions. It would not automatically establish that the procedure improves clinical decisions or outcomes. Those are distinct questions, and the registry record does not report results addressing them.
The record also does not provide a statistical plan, a sample-size justification, interim analyses, or a detailed endpoint analysis method. The description of a feasibility assessment with enrollment of 20 participants, approximately 1 year, is not a substitute for a statistical justification. Without a stated method and numerical outcome, the analysis cannot be independently checked or interpreted beyond the qualitative statement recorded.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 1 outcome measure and no analyses. It identifies sentinel node identification rate as the primary outcome and states that no analysis was conducted due to low detection rate. It does not report a statistical analysis plan, a prespecified testing hierarchy, or any completed inferential analysis. Multiplicity procedures and adjustments are therefore not reported in the registry record.
As a general statistical concept, multiplicity arises when several outcomes, time points, subgroups, or hypotheses are assessed. Repeated testing can increase the chance of a misleading positive result if methods do not account for the number and structure of analyses. The record lists one outcome measure, but it does not provide enough detail to determine whether additional planned analyses existed. No adjustment should be presumed either to have been used or to have been unnecessary.
The analysis population is described as per protocol, but the record says no analysis was conducted. It does not define per-protocol eligibility, identify an analyzed population, or report participant disposition for the primary endpoint. Handling of missing or unevaluable endpoint observations is not reported in the registry record. The endpoint count, denominator, and missing-data method are also not reported, so no sensitivity analysis can be assessed.
These gaps matter because an outcome rate depends on which observations are included and how absent or unevaluable results are treated. The registry record does not permit a judgment about whether those choices could affect the result. No multiplicity or missing-data method can be inferred from the study design or the endpoint label alone.
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 |
|---|---|---|---|
| Intraoperative Lymphatic Mapping | 0 | 5 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Intraoperative Lymphatic Mapping | 0 of 5 |
The registry record lists the intraoperative lymphatic mapping group with 5 at risk for serious adverse events and 0 affected. It also lists 5 at risk for other adverse events and 0 affected. These are the recorded event figures for the group; they should not be confused with the primary sentinel node identification outcome.
Zero affected in the recorded group is a count, not proof that an event could not occur. As a general statistical point, safety estimates based on a small group can be uncertain, and a count of zero does not establish absence of risk. The registry record does not provide an uncertainty interval for these event figures or additional details about event collection and follow-up.
Deaths are recorded as not reported in the registry record. No serious adverse event terms are listed. The adverse event entries do not provide further event descriptions or a comparison with another group. Because the study has a single group and no comparator, these counts cannot support a controlled comparison of safety.
12. What the Result Does, and Does Not, Mean
The registry record documents a study of intraoperative lymphatic mapping for sentinel node identification in women with endometrial cancer. It identifies a specific procedural feasibility question and a primary endpoint intended to measure sentinel node identification. It also records enrollment of 5, a terminated status, and the statement that no analysis was conducted due to low detection rate.
What the result does not provide is a numerical identification rate. There is no reported count of identified nodes, no endpoint denominator, and no uncertainty measure. The qualitative wording about low detection cannot be converted into a rate or used to assess its precision. The result therefore does not permit a quantitative estimate of feasibility from the registry record.
The single-group design also limits what could be learned from any descriptive rate. Without a comparator, the study cannot provide a controlled estimate of performance relative to another mapping method or approach. The record does not report diagnostic accuracy against a reference standard or outcomes beyond the stated endpoint. It should not be interpreted as evidence for a comparative benefit or lack of benefit.
Enrollment of 5 is lower than the feasibility assessment enrollment of 20 described in the primary outcome text. The registry record does not explain this difference or the reason for termination. Those details make the recorded study experience limited, but they do not establish why enrollment stopped or what would have happened with additional participants.
The appropriate conclusion is narrow: the registry describes the intended procedure and endpoint, reports a qualitative low-detection statement, and records that no analysis was conducted. It does not supply the numerical information required to estimate the endpoint or its precision. No conclusion about comparative performance or broader clinical outcomes follows from the posted results.
13. Why This Trial Matters Statistically
This trial is statistically instructive because it shows the difference between an endpoint being named and an endpoint being numerically reported. The registry identifies sentinel node identification rate as the primary outcome and describes how mapping was to be performed. Yet it also states that no analysis was conducted due to low detection rate, and no endpoint count or rate is reported. A defined question does not by itself yield an interpretable estimate.
The contrast between the stated feasibility assessment and actual enrollment is also important. The primary outcome description refers to enrollment of 20 participants, approximately 1 year, while the registry lists enrollment of 5 and a terminated status. Without an explanation or analysis, readers should not treat the planned feasibility assessment as completed or assume the stated target was met.
The design clarifies the scope of possible inference. A single-group study can describe what happened among participants who received a procedure, but without a comparator it cannot separate that experience from what might occur under another approach. This distinction is central when interpreting a procedural feasibility study and prevents a descriptive question from being mistaken for a comparative one.
Finally, the record illustrates why counts, denominators, analysis populations, and uncertainty measures are necessary for interpreting rates. The registry supplies none of these for the primary endpoint. The safety entries report counts, but they do not replace an analysis of feasibility or establish comparative safety. Statistical interpretation depends not only on a study’s stated objective, but also on the results and analysis details recorded for that objective.
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 primary limitation for interpretation is that the registry record reports no numerical sentinel node identification result. It gives no outcome count, denominator, rate, or confidence interval. Its qualitative statement that no analysis was conducted due to low detection rate does not indicate the size or precision of the endpoint result.
The recorded enrollment is 5, while the primary outcome description refers to a feasibility assessment with enrollment of 20 participants, approximately 1 year. The record does not explain the difference or the reason the study was terminated. It does not report whether all enrolled participants underwent the procedure or had an evaluable endpoint.
The single-group design, with allocation recorded as NA and masking recorded as none, has no control comparison. The record does not report a comparator, a diagnostic reference-standard analysis, or a statistical analysis plan. It also does not explain the operational criteria for a successful identification or how the per-protocol population was defined.
Missing endpoint handling, participant disposition, and any sensitivity analysis are not reported in the registry record. The safety entries contain event counts but do not include further event descriptions or uncertainty measures. These limitations prevent a quantitative evaluation of the primary endpoint and restrict interpretation to the study design, recorded enrollment, and qualitative statement about detection.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Hysteroscopic Lymphatic Mapping for Endometrial Cancer — NCT00671606.
- Registry record last updated 2016-05-27; status last verified 2012-04.
- Results first posted 2011-07-27.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT00671606, “Hysteroscopic Lymphatic Mapping for Endometrial Cancer,” is listed as a phase 2, single-group study sponsored by M.D. Anderson Cancer Center. The registry record lists a start of 2008-04, primary completion of 2010-06, terminated status, and enrollment of 5.
The study evaluated intraoperative lymphatic mapping using hysteroscopic tracer injection for sentinel node identification in women with endometrial cancer. The primary endpoint was sentinel node identification rate. The record describes feasibility assessment with enrollment of 20 participants, approximately 1 year, but states that no analysis was conducted due to low detection rate. A numerical primary result is not reported in the registry record.
The safety entries list 0 serious adverse events and 0 other adverse events among 5 at risk in the intervention group. Deaths are not reported in the registry record.