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 Early Increase in Blood Flow (EIBS) in the Duodenum in Patients With Pancreatic Cancer (NCT01015820), a non-randomized na study. The primary outcome is Deoxyhemoglobin Concentration (DHb).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01015820 |
| Phase | NA |
| Condition | Pancreatic Cancer |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 37 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Mayo Clinic |
| Results posted | Yes |
2. Clinical Question
Population
The study included participants with pathologically confirmed pancreatic adenocarcinoma and participants without pancreatic adenocarcinoma. The control group underwent EGD with EUS for abdominal pain. For the primary analysis, 14 participants in the cancer group and 15 participants in the control group were included.
Intervention
During EUS, investigators used the 4D-ELF device to measure blood flow in the duodenum. This investigational device measured spectroscopic signals at peri-ampullary locations.
Comparator
The comparison was between the cancer group and the control group. This was a non-randomized study, and the groups were not a like-for-like control comparison. The registry record describes different group characteristics and reasons for undergoing EGD with EUS.
Primary question
The investigators hypothesized that pancreatic cancer could be detected through changes in early increase in blood supply in surrounding normal-appearing duodenal tissue. The primary endpoint was mean deoxyhemoglobin concentration, used as a marker for EIBS. The registry record does not report the group means or their confidence intervals, so the direction and precision of the observed comparison cannot be assessed from this record.
3. Trial Design
This was a completed, non-randomized, parallel-group study sponsored by Mayo Clinic. The registry lists the phase as NA and masking as none. The study enrolled 37 participants. Its recorded start was 2010-06, and primary completion was 2012-10.
The cancer group consisted of participants with pathologically confirmed pancreatic adenocarcinoma. They received EGD with EUS, during which the 4D-ELF device measured duodenal blood flow. The control group consisted of participants without pancreatic adenocarcinoma who received EGD with EUS for abdominal pain; the device was used during the procedure as well.
Because assignment was not randomized, the group comparison is observational rather than a randomized treatment comparison. Group membership was defined by cancer status, and the groups also differed in the stated indication for EGD with EUS. Differences in the measured endpoint could therefore reflect group characteristics or other factors, as well as any relationship between cancer status and duodenal DHb. The registry record does not report an adjustment strategy that would address such differences.
The device was described as investigational for the study use. The registry summary states that the FDA allowed its use in this research study, while noting that it was not approved for routine clinical use or for the use described. The study procedure and endpoint concern measurement, not assignment to a therapeutic intervention.
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.
Before assignment: 37 patients were enrolled in the study. Of these, 5 patients with neuroendocrine tumors and 2 patients with duodenal anatomy limiting the use of the probe were excluded because of screen failure.
Overall Study
| Stage | Cancer Group | Control Group |
|---|---|---|
| STARTED | 15 | 15 |
| COMPLETED | 14 | 15 |
| NOT COMPLETED | 1 | 0 |
Reasons for not completing this period:
| Reason | Cancer Group | Control Group |
|---|---|---|
| Suboptimal measurements | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: Among the 15 participants in the cancer group, 1 participant was excluded from the final analysis due to suboptimal measurements. Therefore 14 participants in the cancer group and 15 participants in the control group were included in the analysis population.
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: Among the 15 participants in the cancer group, 1 participant was excluded from the final analysis due to suboptimal measurements. Therefore 14 participants in the cancer group and 15 participants in the control group were included in the baseline analysis population.
| Characteristic | Unit | Cancer Group | Control Group | Total |
|---|---|---|---|---|
| Participants analysed | 14 | 15 | 29 | |
| Age, Continuous | years | 72 (SD 10) | 63 (SD 11) | 67 (SD 12) |
| Sex: Female, Male: Female | Participants | 3 | 6 | 9 |
| Sex: Female, Male: Male | Participants | 11 | 9 | 20 |
| Region of Enrollment: United States | participants | 14 | 15 | 29 |
6. Primary Endpoint
The registry lists the primary outcome as Deoxyhemoglobin Concentration (DHb), measured over Completion of study procedure (endoscopic ultrasound), approximately 30 minutes from procedure initiation.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | alpha units |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was mean deoxyhemoglobin concentration, abbreviated DHb, measured in alpha units. Deoxygenated hemoglobin is hemoglobin without bound oxygen. In this study it served as a marker for early increase in blood supply, or EIBS, in the duodenum.
The investigators determined DHb spectroscopically from five peri-ampullary locations. Measurements were taken at completion of the endoscopic ultrasound procedure, approximately 30 minutes from procedure initiation. The endpoint was intended to assess whether a signal in surrounding normal-appearing duodenal tissue differed between participants with pancreatic adenocarcinoma and controls.
As general statistical context, a continuous endpoint such as concentration can be summarized by a group mean, while a confidence interval communicates uncertainty around that estimate. The registry record identifies the planned summary as a mean with a 95% confidence interval, but does not report the numerical means or intervals. The size, direction, and precision of the group comparison therefore cannot be described from the available record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies DHb concentration as the primary outcome and gives the analysis population: 14 participants in the cancer group and 15 participants in the control group. It also reports that 1 participant from the cancer group was excluded from the final analysis because of suboptimal measurements. However, the record does not report the observed group means or their 95% confidence intervals. Without those estimates, it is not possible to state which group had a higher mean, how large any difference was, or how uncertain the estimates were.
This absence of numerical outcome estimates also prevents assessment of whether the observed data were compatible with a small or large difference. A confidence interval, when reported, helps show the range of values consistent with the data under the analysis assumptions; its width conveys precision. No interval is available in the registry record, so the precision of the primary result cannot be judged. A significance test result is also not reported in the registry record.
The study's non-randomized structure matters when interpreting any group contrast. The cancer and control groups were defined by disease status, and controls underwent EGD with EUS for abdominal pain. Such groups may differ in ways beyond cancer status. An observed difference, if reported, would be an association in this study population and would not by itself establish that cancer caused a change in DHb or that DHb can accurately identify cancer in other settings.
The registry lists 37 enrolled participants, but the primary analysis population is described separately. Those figures refer to different aspects of the study record and should not be treated as interchangeable. The stated exclusion due to suboptimal measurements also means the primary analysis did not include every cancer-group participant described as enrolled in that group. The registry record does not report further details about the excluded measurement or sensitivity analyses.
Accordingly, the record supports a description of the research question, design, endpoint, and analysis population, but not a numerical interpretation of the primary result. It does not establish diagnostic accuracy, clinical usefulness, or performance outside the study groups. Those conclusions would require outcome estimates and additional evidence about how the measurement distinguishes relevant patients in the intended setting.
9. Statistical Methods Explained
What does a mean describe?
DHb is a continuous measurement, and the registry identifies the primary summary as a mean. In general, a mean describes the arithmetic center of a set of measurements. It can be useful for comparing the average measurement between groups, but it does not describe the full distribution. A mean alone does not show whether measurements cluster closely around it or vary substantially, and it can be influenced by unusually high or low observations.
The registry specifies a 95% confidence interval alongside the mean. In general, a confidence interval expresses statistical uncertainty in an estimate under the assumptions of the method used to calculate it. A narrower interval indicates greater precision than a wider interval, though precision is not the same as freedom from bias. The interval method is not reported in the registry record, and numerical intervals are not reported there either.
What does a group comparison mean in this design?
The study compared participants with pancreatic adenocarcinoma to controls without pancreatic adenocarcinoma. General statistical interpretation of a group contrast depends not only on the measurement but also on how groups were formed. Random allocation can balance measured and unmeasured characteristics on average; this study was non-randomized, so that protection does not apply. The groups were defined by cancer status, and the control group underwent the procedure for abdominal pain. Any observed difference could be associated with other differences between the groups.
The posted record does not describe an adjusted analysis, a model for covariates, or a method for handling clustering among measurements from the peri-ampullary locations. It therefore does not support attributing a group contrast to cancer status alone. A statistical adjustment, if performed, would need to be described to assess what factors were considered and how the estimate should be interpreted.
Why can measurement quality affect analysis?
The primary analysis excluded 1 cancer-group participant because of suboptimal measurements. In general, excluding measurements that do not meet quality criteria can be reasonable, but the consequences depend on why measurements were suboptimal and whether exclusion relates to the underlying measurement or group. The registry record does not explain the specific quality issue, state whether exclusion criteria were set in advance, or report a sensitivity analysis that includes or otherwise evaluates the excluded participant.
Measurement at five peri-ampullary locations creates a further analytic consideration. General statistical methods must account for whether multiple location readings are combined within a participant or treated as separate observations. The registry describes the endpoint as a DHb concentration determined from those locations, but does not report the aggregation method or the handling of within-participant correlation. The analysis population is described in participants, so the unit of analysis appears to be participant-level in the outcome description; the exact calculation is not reported in the registry record.
What do the planning assumptions describe?
The registry's planning illustration is based on the observed effect, uses a two-sided significance level of 0.05, assumes equal allocation between the arms, and uses a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. General sample-size planning asks how much information may be needed to detect a specified effect under assumptions about variability, significance level, allocation, and statistical method. Such a calculation is a planning illustration, not evidence that the study was designed with those assumptions and not a measure of observed power.
The registry record does not report the study's own sample-size justification or design assumptions. Nor does it provide the numerical primary effect estimate in this record, so the planning illustration cannot be independently interpreted from the outcome details stated. Planned sample size and achieved precision are distinct: actual precision depends on the observed data and analysis, which requires the estimates and intervals.
What cannot be inferred from missing test details?
The record reports two outcome measures and two analyses, but does not specify the full statistical analysis plan, the test used for the primary comparison, or any adjustment for multiple testing. General methods for continuous outcomes can include several approaches, and their suitability depends on data distribution, design, and analysis assumptions. No particular test or model should be inferred when it is not reported.
The registry record also does not report interim analyses or stopping rules. Their presence or absence cannot be inferred from the completed status. In general, interim examination of accumulating data can affect how statistical evidence is interpreted, but no such procedure is described in this record. Numerical results and the analysis details would be needed for a fuller assessment of the statistical evidence.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists two outcome measures and two analyses, but the available record does not identify all outcomes, provide their results, or describe a multiplicity strategy. When several outcomes or analyses are considered, general statistical practice distinguishes a prespecified primary question from additional questions and considers how repeated testing affects the chance of false-positive findings. The primary endpoint is identified as DHb concentration; whether and how multiplicity was addressed is not reported in the registry record.
The primary analysis population excludes 1 cancer-group participant because of suboptimal measurements. The record reports 14 cancer-group participants and 15 control-group participants in the analysis. It does not describe the measurement-quality criteria, whether the criteria were prespecified, or any analysis assessing the effect of the exclusion. Missing-data methods beyond this stated exclusion are not reported in the registry record.
The record does not describe an intention-to-treat analysis or another named analysis population. Because the study was non-randomized, an intention-to-treat framework cannot be assumed from the design description. The endpoint is a measurement collected during a procedure, but the registry does not report whether any other measurements were unavailable or how such cases were handled.
The record also does not state whether interim analyses were conducted, or whether a statistical analysis plan was finalized before examining outcomes. These details are not reported in the registry record, so the analysis decisions and their timing cannot be evaluated.
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 |
|---|---|---|---|
| Cancer Group | 0 | 14 | 0.0% |
| Control Group | 0 | 15 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Cancer Group | 0 of 14 |
| Control Group | 0 of 15 |
The registry reports no serious adverse events affecting participants in either group: 0 of 14 in the cancer group and 0 of 15 in the control group. It also reports no other adverse events affecting participants in either group: 0 of 14 in the cancer group and 0 of 15 in the control group. These are the event figures recorded for the stated groups; they do not establish that the risk of an event is absent.
General statistical context is important when reading zero observed events. A zero count means no affected participants were recorded in the stated analysis of adverse events, but it does not prove that an event cannot occur. The amount of uncertainty depends on the number observed, the population monitored, and the duration and completeness of follow-up. The registry record does not report a safety follow-up duration.
Death counts are not reported in the registry record. No serious adverse event terms are listed. These safety entries should be read as registry reporting, not as a comprehensive estimate of safety in other populations or uses of the investigational device.
12. What the Result Does, and Does Not, Mean
The study addresses whether DHb measured in the duodenum might differ between participants with pancreatic adenocarcinoma and controls without the disease. It describes use of 4D-ELF during EUS and defines DHb as a marker for EIBS. This establishes the measurement question examined, but the registry record does not report the primary means or confidence intervals needed to describe the observed result.
Even if a group difference were available, a difference in mean DHb would not by itself show that the measurement can reliably identify cancer in an individual. Group averages do not provide diagnostic sensitivity, specificity, predictive values, or a validated decision threshold. Those performance measures are not reported in the registry record. Nor would an association in this non-randomized comparison establish that pancreatic cancer caused the measured signal.
The study's context also limits what can be concluded. The control group consisted of people without pancreatic adenocarcinoma who underwent EGD with EUS for abdominal pain, while the cancer group had pathologically confirmed adenocarcinoma. The registry does not establish that these groups represent the full range of people in whom a diagnostic test might be considered. A result in this setting would not, by itself, establish performance in a different clinical population.
The device was investigational for the described use. The record presents a research hypothesis and a procedure-based measurement, not evidence of routine clinical utility. The available information therefore supports describing the design and intended biomarker question, but not a conclusion about the measurement's diagnostic performance or clinical role.
13. Why This Trial Matters Statistically
Statistically, the study illustrates the distinction between a plausible biomarker hypothesis and evidence that can be evaluated quantitatively. The investigators proposed measuring EIBS in surrounding normal-appearing duodenal tissue and used DHb concentration as the primary marker. The endpoint, measurement timing, and analysis population are described, but numerical results are necessary to evaluate the size and precision of the group comparison.
The non-randomized design is also central to interpretation. The cancer and control groups were selected according to disease status, and controls underwent EGD with EUS for abdominal pain. This makes the comparison potentially informative about an association in the studied groups, but limits causal interpretation and generalization. Statistical methods cannot remove design limitations unless relevant sources of difference are measured and addressed; the registry record does not report an adjustment strategy.
The stated exclusion for suboptimal measurements highlights how data quality and analysis populations affect a result. Transparent criteria and sensitivity analyses can help readers understand whether exclusions might change an estimate. Those details are not reported in the registry record.
Finally, the absence of group means and confidence intervals prevents assessment of the primary endpoint's observed direction, magnitude, or precision. A clear description of the hypothesis and methods is not a substitute for numerical outcome reporting. The record therefore shows why estimates, uncertainty, and analysis details are all needed to judge a clinical measurement study.
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 most immediate limitation of the registry information is that it does not report the primary group means or 95% confidence intervals. The outcome's direction, magnitude, and precision cannot be assessed from the record. A numerical comparison is also needed to interpret the planning illustration that is based on the observed effect.
The non-randomized design limits causal interpretation. Cancer status defined the groups, and the control participants underwent EGD with EUS for abdominal pain. The registry record does not report whether group differences were addressed through adjustment or other methods. The comparison therefore cannot be assumed to isolate cancer status from other characteristics.
The primary analysis excluded 1 cancer-group participant for suboptimal measurements. The record does not describe the quality criteria, explain the measurement issue, or report sensitivity analyses. It also does not describe how measurements from five peri-ampullary locations were combined or how within-participant measurement variation was handled.
Details needed to assess statistical reporting are also unavailable: the specific test or model, treatment of missing data beyond the stated exclusion, multiplicity methods, and interim analyses are not reported in the registry record. Safety follow-up duration and death counts are not reported either.
Finally, the registry describes selected groups and an investigational device used during EUS. It does not report diagnostic accuracy measures or establish whether the study population represents other settings. These limitations restrict conclusions about diagnostic performance and broader applicability.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Early Increase in Blood Flow (EIBS) in the Duodenum in Patients With Pancreatic Cancer — NCT01015820.
- Registry record last updated 2014-07-16; status last verified 2014-07.
- Results first posted 2014-07-02.
- 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
This completed, non-randomized, parallel-group study examined DHb concentration measured with 4D-ELF during EUS. The registry lists 37 participants enrolled, a start of 2010-06, primary completion in 2012-10, and Mayo Clinic as sponsor.
The primary endpoint was mean DHb in alpha units, measured spectroscopically from five peri-ampullary locations at completion of the procedure, approximately 30 minutes from its initiation. The primary analysis included 14 participants in the cancer group and 15 in the control group; 1 cancer-group participant was excluded for suboptimal measurements.
The registry record does not report the primary group means or confidence intervals. It reports 0 serious adverse events and 0 other adverse events in each group; death counts are not reported in the registry record.