Impact of Ga-68 DOTATOC PET-CT Imaging in Management of Neuroendocrine Tumors: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Impact of Ga-68 DOTATOC PET-CT Imaging in Management of Neuroendocrine Tumors (NCT02441062), a na phase 2 study. The primary outcome is Number of Participants With a Change in Treatment Management Based on Findings of the Gallium Ga 68-edotreotide PET/CT Scan.

2. Clinical Question

The study's stated purpose was to assess whether the tumor could be identified by PET imaging and whether the imaging information would change tumor management. Referring physicians were asked to document management and treatment strategy before the scan and after its findings became available. The primary endpoint therefore concerns a documented change in management, rather than a direct comparison of clinical outcomes between treatment groups.

The registry lists an enrollment of 122 and says that the study stopped early, with 114 of the 122 patients enrolled analyzed for the outcome measure. It does not report the number of analyzed participants who had a management change. Consequently, the central descriptive result needed to answer the primary question is not reported in the registry record. The single-group, pre-scan/post-scan approach can describe reported changes following access to imaging information, but it does not by itself establish what would have happened without the scan.

3. Trial Design

This was a phase 2, single-group study with an enrollment of 122. The registry lists the study as completed. Allocation is recorded as NA, masking as none, and the model as single group. These entries indicate that the registered design was not a randomized, masked comparison between separate intervention and control groups.

Participants received 68Ga-DOTATOC and underwent PET/CT imaging. The intervention description also allows for a second scan for restaging after therapy 12-36 months after the first scan. The registry does not say how many participants received a second scan, so the possibility of repeat imaging should not be read as evidence that all participants underwent it.

The primary outcome description says that referring physicians were asked to complete forms about management and treatment strategy before PET and after the PET-CT information was available. It describes the approach as using the same methodology as the National Oncologic PET Registry, with change-in-management criteria modified for treatment strategies used in neuroendocrine tumors. The record does not give further detail on the criteria, how responses were classified, or how disagreements or incomplete forms were handled.

The outcome population description states that the study stopped early and that 114 of the 122 enrolled participants were analyzed for the outcome measure. The reason for stopping early, the reason some enrolled participants were not analyzed, and the timing of that decision are not reported in the registry record. The enrollment figure should therefore not be mistaken for the number included in the primary endpoint analysis.

The registry lists one outcome measure and no analysis entries. The protocol's statistical analysis plan, any sample-size justification, and any interim analyses are not reported in the registry record. Those omissions limit what can be concluded about the planned analysis and the interpretation intended by the investigators.

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: Study stopped early, 114 of the 122 patients enrolled were analyzed for outcome measure

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 a Change in Treatment Management Based on Findings of the Gallium Ga 68-edotreotide PET/CT Scan, measured over 36 months.

The primary endpoint is the number of participants with a change in treatment management based on findings from the gallium Ga 68-edotreotide PET/CT scan. Physicians were to report management and treatment strategy before PET and again after the imaging information was available. The endpoint thus focuses on a change in the recorded management decision associated with access to scan findings.

Management change is useful as a process measure because it describes whether new diagnostic information is followed by a different recorded plan. It is not the same as measuring tumor identification accuracy, a change in tumor size, survival, symptoms, or the benefit of a particular treatment. The registry's stated research purpose includes both tumor identification and management impact, but the listed primary endpoint is the count of participants with a management change.

The outcome timeframe is 36 months. The endpoint description does not provide the observed count, the criteria used to define a qualifying change, or a breakdown of the types of management changes. The population note says 114 of the 122 enrolled participants were analyzed for this outcome measure. Without the endpoint count and further classification details, the magnitude and nature of any management impact cannot be assessed from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the endpoint count?

The endpoint is a count of participants with a change in treatment management based on the scan findings. It is a binary participant-level outcome in the sense that each analyzed participant is classified as having or not having the specified event. The registry does not report the number classified in either way, nor does it describe in detail how the classification was applied.

General statistical context: a count is often easier to interpret when accompanied by its denominator, because readers can see both how many people experienced an event and how many were assessed. The registry states that 114 participants were analyzed for the outcome measure, but the event count is not reported. Without both pieces, a proportion or rate cannot be calculated from the record. No such calculation should be inferred from the enrollment number.

What can a before-and-after design establish?

Physicians were to record management plans before the PET scan and after the imaging information was available. This structure can capture whether the recorded plan changed across those assessments. It does not include a separate group whose management was assessed without access to the scan findings. As a result, the design does not provide a direct comparison that separates changes associated with the imaging information from changes that might have occurred for other reasons.

General statistical context: random assignment can help balance other influences between groups, while a concurrent control group can provide a reference for what might occur without the intervention. Neither feature is recorded for this study: allocation is NA and the model is single group. That does not invalidate a descriptive count of documented changes, but it narrows causal interpretation. A change in management is an observed process outcome, not proof that the scan alone caused the change or that the change improved health outcomes.

How should the analysis population be read?

The registry says the study stopped early and that 114 of the 122 enrolled participants were analyzed for the outcome measure. It does not state why the study stopped early or why not all enrolled participants were analyzed. It also does not report whether the analysis used all available records, a prespecified subset, or a particular rule for incomplete physician forms.

General statistical context: an analysis population is the set of participants whose data contribute to a particular result. Different rules for including participants can affect the interpretation of an estimate, especially when outcome information is unavailable. A reader would need the reasons for exclusions and the handling of missing assessments to judge whether the analyzed group may differ in relevant ways from those not analyzed. Those details are not reported in the registry record.

What does the registry say about statistical analysis?

The registry lists one outcome measure and zero analysis entries. It does not report a statistical test, an effect estimate, an interval estimate, or a model for the primary endpoint. The statistical analysis plan, including any prespecified comparison or adjustment, is not reported in the registry record. No particular method should be attributed to the investigators on the basis of the endpoint description alone.

General statistical context: estimates are more informative when accompanied by a measure of uncertainty, such as a confidence interval. Such an interval reflects uncertainty under the method's assumptions; it does not account automatically for every source of bias, missing information, or lack of a comparator. Since no result estimate or uncertainty interval is reported for the primary endpoint, its statistical precision cannot be assessed.

How do planning calculations differ from observed results?

Any sample-size illustrations associated with this analysis are planning examples based on stated assumptions, not observed outcomes and not the study's own design justification. The registry record does not report a sample-size justification. An illustration based on an assumed effect cannot establish what effect was observed, whether the study had adequate precision, or whether a hypothesis test would have been significant.

General statistical context: planning calculations depend on assumptions about the effect to detect, the allocation, the significance level, and the statistical model. If those assumptions do not match a study's actual design or outcome data, the illustration is not a substitute for an analysis. The record describes a single-group design, while the stated general planning assumptions refer to equal allocation between two arms. Such planning assumptions should not be mistaken for the design that was conducted or for evidence of observed power.

For this study, the main methodological conclusion is limited by the absent outcome result and absent analysis details. The registry gives enough information to identify the endpoint, the single-group structure, and the analyzed population size, but not enough to reconstruct the primary analysis or quantify its result.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, the management-change count, and zero analysis entries. It does not report the complete statistical analysis plan, a hierarchy of outcomes, or a multiplicity adjustment. The number of outcomes listed does not establish that no other analyses were planned or conducted; it only describes what is recorded in the registry entry.

General statistical context: multiplicity arises when several hypotheses or outcomes are tested, because repeated testing can increase the chance of obtaining at least one apparently unusual result by chance. Methods for handling multiplicity depend on the planned questions and analysis. Since the registry does not report a testing plan or analysis results, it is not possible to assess whether multiplicity was relevant or how it was handled.

The outcome population description says that 114 of 122 enrolled participants were analyzed and that the study stopped early. Reasons for stopping and for the difference between enrollment and analysis are not reported. The record does not state how missing outcome information was handled, whether any participants were excluded, or whether the analysis population was defined in advance. It also does not report sensitivity analyses to examine the effects of missing data.

General statistical context: missing outcome information can affect interpretation if participants with unavailable data differ from those with recorded outcomes. The direction or size of any such effect cannot be determined without additional information. No assumption about the reasons for missing assessments, or their influence on the result, is warranted from the registry entry.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The registry's safety figures list 122 participants at risk in the 68Ga-DOTATOC PET/CT group. It reports 0 participants with serious adverse events, 42 with other adverse events, and 2 deaths. These are separate registry categories and should be read as counts, not as evidence about the cause of an event.

The record does not list serious adverse event terms. It also does not describe the specific other adverse events, their severity, their timing, or whether they were considered related to the imaging intervention. The listed death count is not accompanied by cause or attribution information. Therefore, these figures alone do not establish that an event was caused by the scan, nor do they establish that an event was unrelated.

General statistical context: safety counts depend on the population assessed, the event definitions, the observation period, and the completeness of reporting. The registry figures use 122 as the number at risk, while the outcome measure population description says 114 participants were analyzed for the primary outcome. These different denominators refer to the registry's safety and primary-outcome reporting, respectively; the record does not explain further how follow-up or reporting differed.

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

The study addresses whether 68Ga-DOTATOC PET/CT findings were associated with a documented change in treatment management for participants with tumors described as carrying somatostatin receptors. The design collected physician assessments before the scan and after its information was available. This makes management change the central reported question, rather than a comparison of clinical outcomes between randomized groups.

The registry record does not report the observed count of participants with a management change. It therefore cannot show how often a change occurred or how precise an estimate of that frequency would be. The record reports that 114 of the 122 enrolled participants were analyzed for the outcome measure, but this does not substitute for the missing event count.

A change in management, if documented, would describe a change in a plan. It would not on its own establish that the imaging information caused the change, that the new plan was better, or that participants had improved clinical outcomes. Answering those questions would require outcome information and a design capable of supporting the relevant comparison. Neither a comparative result nor a clinical outcome effect is reported for this endpoint.

The study is recorded as completed, but its outcome result is absent from the registry entry. The appropriate conclusion is not that management did or did not change; the record does not report the count needed to make that statement. Likewise, the safety counts should be interpreted as registry-reported events without assuming causation or clinical meaning not stated in the record.

In short, the entry describes the intended question, the single-group design, and the size of the analyzed outcome population. It does not provide the primary result needed to quantify the management impact. Conclusions should remain limited to those design and reporting details.

13. Why This Trial Matters Statistically

This study is statistically notable because its primary question is a measure of decision impact: whether physicians recorded a different management strategy after PET/CT information became available. Such endpoints can describe how diagnostic information is used in practice, rather than only whether an imaging procedure identifies a tumor. The registry also specifies a pre-scan and post-scan documentation process, making the intended measurement approach apparent.

At the same time, the single-group structure determines what the result could establish. Without a parallel control group, a pre/post difference in recorded plans would be descriptive and could not isolate the scan's contribution from other changes in clinical information or circumstances. This is an important distinction when interpreting a management endpoint as evidence about causation or downstream outcomes.

The record also illustrates why the outcome estimate itself matters. It identifies a primary outcome and says that 114 of 122 enrollees were analyzed, but it does not report the number with a management change. Without the observed count, readers cannot assess the magnitude of the endpoint or its precision. An endpoint definition and analysis-population statement are not substitutes for the result.

General statistical context: clear reporting of event counts, denominators, uncertainty, missing-data handling, and analysis methods allows readers to distinguish the observed data from assumptions and limitations. Here, several of those details are not reported in the registry record. The study remains useful for understanding the intended design and question, while the absent result and analysis details limit statistical interpretation.

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 interpreting the study is that the registry does not report the primary endpoint count. Although the endpoint is defined as the number of participants with a change in management and the outcome population is described, the number who experienced the event is not reported in the registry record. No frequency, effect estimate, or uncertainty interval can therefore be described.

The study is recorded as a single-group design with allocation listed as NA and masking listed as none. There is no randomized control group in the registry description. A documented change in management after the scan would not, by itself, distinguish the effect of the scan from other influences on decisions, and it would not demonstrate a benefit in clinical outcomes.

The outcome population description says the study stopped early and that 114 of the 122 enrolled participants were analyzed. The reason for early stopping, reasons some enrollees were not analyzed, and the handling of missing forms or other unavailable outcome information are not reported. The record does not describe whether this analysis population was prespecified or whether sensitivity analyses were conducted.

The registry gives limited detail about the definition and classification of a management change. It refers to modified criteria for treatment strategies used in neuroendocrine tumors but does not state the criteria themselves or how changes were categorized. It also does not report the statistical analysis plan, sample-size justification, or interim analyses.

The intervention description says that a second scan for restaging after therapy was possible 12-36 months after the first scan. The number of participants who received a second scan is not reported. The safety record gives event counts but not detailed event descriptions, timing, or attribution. These omissions limit interpretation of both the management endpoint and the safety counts.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Impact of Ga-68 DOTATOC PET-CT Imaging in Management of Neuroendocrine Tumors — NCT02441062.
• Registry record last updated 2020-12-21; status last verified 2020-12.
• Results first posted 2020-12-21.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry describes a completed phase 2 study of 68Ga-DOTATOC PET/CT in a single group, with 122 participants enrolled. Its stated purpose was to assess tumor identification by PET and changes in tumor management after imaging information became available.

The primary outcome was the number of participants with a management change based on the scan findings, assessed over 36 months. Physicians were to record management before and after PET. The registry says the study stopped early and that 114 of the 122 enrollees were analyzed for this outcome, but it does not report the outcome count or a statistical analysis result.

The design has no parallel control group. The registry lists 0 participants with serious adverse events, 42 with other adverse events, and 2 deaths among 122 at risk; event details and attribution are not reported. The protocol's statistical analysis plan, sample-size justification, and reasons for early stopping are not reported in the registry record.