PET Imaging With 89Zr-DFO-Trastuzumab in Esophagogastric Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for PET Imaging With 89Zr-DFO-Trastuzumab in Esophagogastric Cancer (NCT02023996), a na na study. The primary outcome is Safety as Measured by the Number of Participants Who Experienced Toxicity.

2. Clinical Question

The scientific aim described in the record is broader than the primary safety measure. In the first group, investigators sought to learn about scan timing, blood persistence, organ dosimetry, and tolerability. The record says that, based on what was learned from that group, people in Group 2 no longer needed serial scans or serial blood draws. It does not provide detailed group-specific results or explain the decision criteria for that change.

Because there is no control group, this study is not designed to estimate a comparative treatment effect. Its single-cohort structure instead supports description of imaging procedures and observed outcomes within the enrolled cohort. The record does not report a primary endpoint result, so the stated safety question cannot be answered from the listed primary outcome information alone.

3. Trial Design

This is a completed pilot study of PET imaging with 89Zr-DFO-trastuzumab in esophagogastric cancer. The registry lists the phase as NA, the allocation as NA, masking as none, and the model as single group. The sponsor is Memorial Sloan Kettering Cancer Center. Enrollment is listed as 42. The record gives a start date of 2013-12 and a primary completion date of 2023-06-27.

The intervention listing includes 89Zr-DFO-trastuzumab and PET imaging. The brief description says the study used a cohort expansion and that its data are appropriately reported as one study cohort. It also distinguishes an initial group, in which investigators sought to establish imaging timing and assess blood persistence and tolerability, from a later group for which serial scans and serial blood draws were no longer needed based on what had been learned. The available description does not specify a separate analytic comparison between those groups.

The absence of random allocation and a comparator means that outcomes are descriptive rather than a randomized comparison between study arms. No masking was used. These design features do not prevent reporting observed counts, but they limit what can be attributed to the imaging procedure and what can be compared with an alternative approach.

The registry lists biologic half-time as a secondary outcome. It also reports 3 outcome measures and 0 analyses, but does not give further analysis details in the information available for this record. The registry does not report a statistical analysis plan, a sample-size justification, or details of interim analyses. The sample-size illustrations associated with the posted results are planning exercises based on stated assumptions; they should not be read as the study’s original design or as observed power.

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: This study is based on a cohort expansion. All data is appropriately reported as there is only one study cohort

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: This study is based on a cohort expansion. All data is appropriately reported as there is only one study cohort

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: This study is based on a cohort expansion. All data is appropriately reported as there is only one study cohort

6. Primary Endpoint

The registry lists the primary outcome as Safety as Measured by the Number of Participants Who Experienced Toxicity, measured over 2 years.

The primary endpoint is the number of participants who experienced toxicity. The registry identifies the unit as participants and states that toxicity is evaluated using CTCAE v4.0 over a timeframe of 2 years. A participant count is a direct way to describe how many people in the cohort had at least one qualifying event under the endpoint definition. It is a count, not a rate or a comparison between treatments.

For a single-group imaging pilot, a safety count can help characterize the events observed during the defined evaluation period. It does not by itself show how frequently similar events would occur in another population, nor does it establish that an event was caused by the imaging procedure. Those interpretations require information about event definitions, attribution, follow-up, and the population assessed.

The record gives the endpoint definition and timeframe but does not report the primary endpoint count in the registry record. Therefore, the primary safety result cannot be described from this outcome entry. Serious adverse event counts are separately reported, and they should not be treated as the primary toxicity result: the registry does not state that the two measures have identical definitions or coverage.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Interpreting a single-group pilot requires separating descriptive summaries from comparative estimates. A descriptive count states how many participants were recorded as having an outcome under a particular definition. A comparative effect asks how outcomes differ between groups or strategies. This registry record describes one study cohort and does not list a control arm, so the reported adverse event counts are descriptive; they do not estimate a contrast against another treatment or imaging strategy.

What does a participant count represent?

The primary outcome is defined as the number of participants who experienced toxicity, with assessment using CTCAE v4.0 over 2 years. A count of participants is distinct from a count of individual events: one participant may experience more than one event, depending on the outcome definition and reporting rules. The registry entry names participants as the unit, but it does not report the primary count or specify additional rules for combining events. The result is therefore not available for interpretation beyond its stated definition.

A count also needs a clear population and follow-up context. The enrollment entry gives 42, while the serious adverse event entry gives 36 at risk. These entries refer to different reported quantities, and the registry does not explain their relationship. It would be inappropriate to assume the at-risk count is the endpoint denominator or to infer why it differs from enrollment. The analysis population and missing outcome handling are not reported in the registry record.

How should uncertainty be considered?

A confidence interval is a statistical range used to express uncertainty around an estimate under a specified method and assumptions. In general, an interval around a participant proportion can communicate how imprecisely the observed data estimate an underlying frequency. The registry record does not list a primary outcome estimate or confidence interval, so this type of precision assessment cannot be made for the primary endpoint. A count alone, even when reported, would not convey uncertainty without an appropriate denominator and analysis.

For event counts, the distinction between the number of affected participants and the number of events is important. The serious adverse event listing gives affected participants and terms, but the registry does not explain whether individuals could contribute to multiple terms or provide event-level detail. The percentages attached to terms are reported as 2.8%; they should be quoted as registry values rather than used to infer an unreported denominator or additional totals.

What does the study design permit?

Because the study is single-group, its outcomes can describe what was observed in the cohort. They cannot, on their own, separate effects of the imaging procedure from other causes or establish a difference relative to an alternative. In general, random allocation can help balance prognostic factors across comparison groups, while masking can reduce some forms of assessment or performance bias. Neither a randomized comparison nor masking is reported for this study. That does not invalidate descriptive safety reporting, but it narrows the conclusions that can be drawn.

The brief description identifies an initial group intended to inform scan timing, blood persistence, and tolerability, and says that serial scans and serial blood draws were no longer needed for Group 2 based on what was learned from Group 1. The record does not report a formal adaptive design, decision thresholds, or analytic methods for comparing groups. The description should therefore be understood as an account of the study conduct, not as evidence of a prespecified statistical decision rule.

What do planning illustrations mean?

In general, sample-size planning asks how much information a future study might need to detect a specified effect under stated assumptions. The planning assumptions associated with this record describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with target effects expressed as fractions of an observed effect. These are planning assumptions, not a description of this single-group pilot’s design. Sample-size illustrations are not observed power and do not show that the study was adequately powered for its primary endpoint. Since the primary endpoint result is not reported, the observed effect underlying any illustration cannot be evaluated from this record.

Over-dispersion is a general concern when outcome variability exceeds what a model assumes; if unaddressed, standard errors may be understated and intervals may be too narrow. The primary endpoint is a participant count, and the registry does not report a fitted model, dispersion estimate, or analysis method. No claim about over-dispersion or model adequacy can be made for this study. More generally, the statistical plan, handling of repeated events, missing data, and prespecified analysis populations are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

Multiplicity concerns arise when several outcomes, time points, subgroups, or statistical tests are examined. In general, conducting many tests can increase the chance of at least one apparently notable result, so a statistical plan may identify a primary analysis or describe how inference is adjusted. The registry lists a primary safety outcome, biologic half-time as a secondary outcome, and 3 outcome measures, but it does not report a multiplicity strategy or a statistical analysis plan. It also lists 0 analyses. The record does not establish which outcomes were analyzed, whether any adjustment was planned, or whether additional exploratory analyses were conducted.

Missing-data handling is also not reported in the registry record. The enrollment entry is 42, and the serious adverse event listing reports 36 at risk. The record does not explain the difference, identify the population used for each endpoint, or state whether participants without complete follow-up were excluded, censored, or handled in another way. No missingness pattern or sensitivity analysis is described. These gaps prevent an assessment of how incomplete follow-up might affect the reported counts.

The record states that the study is reported as one cohort despite describing an initial group and a later group. It does not provide a separate analysis population definition for those groups, nor does it report whether the primary endpoint was assessed in every enrolled participant. The reasons for any exclusions or unavailable outcome data are not reported in the registry record. As a result, the denominator for the primary safety outcome and the applicability of the serious adverse event at-risk count to that endpoint remain unclear.

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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: diarrhea (2.8%), non-cardiac chest pain (2.8%), dehydration (2.8%), back pain (2.8%), renal and urinary disorders - other, specify (2.8%).

The serious adverse event entry lists 2 affected participants among 36 at risk in the PET Imaging With 89Zr-DFO-Trastuzumab group. The separate other adverse event entry also lists 2 affected participants among 36 at risk. The listed serious event terms are Diarrhea, Non-cardiac chest pain, Dehydration, Back pain, and Renal and urinary disorders - Other, specify; each is accompanied by 2.8%.

These figures should be read as registry-reported counts and terms, not as a comparison with another group. The study has one group, and the record does not report a control comparison, event attribution, or details about whether participants could appear under more than one term. The percentages are reproduced as listed; they do not justify inferring unreported denominators or totals.

The record also lists 31 deaths. Timing, cause, relationship to the imaging procedure, and the analysis population for this count are not reported in the registry record. The death entry should not be treated as a primary toxicity result or interpreted as evidence of causation. The primary endpoint result itself is not reported in the registry record, and the serious adverse event figures do not substitute for it.

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

The record describes a completed pilot study of 89Zr-DFO-trastuzumab PET imaging in esophagogastric cancer. Its stated aims include identifying imaging timing, assessing how long the tracer stayed in the blood, and evaluating tolerability. The study is listed as single-group, without masking, and with allocation marked NA. This design allows descriptive reporting of outcomes observed in the cohort, but does not provide a like-for-like comparison with another imaging procedure or a control group.

The primary outcome is the number of participants who experienced toxicity during 2 years, assessed using CTCAE v4.0. The registry does not report the primary outcome count. It therefore does not establish from the listed primary result how many participants experienced toxicity, nor how precise such an estimate would be. Serious adverse event entries are available, including 2 affected participants among 36 at risk and five listed terms at 2.8% each, but those entries do not fill the gap in the primary endpoint result.

The record says that findings from Group 1 informed the decision that Group 2 no longer needed serial scans or serial blood draws. It does not provide the underlying measurements, the criteria used to make that decision, or separate results for the groups. The statement describes the study’s conduct but does not quantify the performance of the imaging approach.

These registry entries do not establish that the procedure caused or prevented any event, and they do not show how outcomes would compare under another strategy. The listed death count is 31, but its timing, cause, and relationship to the procedure are not reported. A completed status indicates the registry marks the study completed; it does not resolve missing endpoint results or analytic details. The results support a limited account of study design and recorded safety entries, not a comparative effectiveness conclusion.

13. Why This Trial Matters Statistically

This study illustrates why the design and outcome definition matter as much as the presence of a numerical result. A participant count for toxicity can be straightforward to describe, but it needs a reported value, a clear denominator, and context about follow-up before readers can assess the observed burden and its uncertainty. Here, the primary endpoint is defined, while its result is not reported in the registry record.

The single-group structure also shapes the statistical question. A pilot can characterize procedures and outcomes within its cohort, and the record describes an initial group that informed the use of serial scans and blood draws in a later group. Without a comparator or random allocation, however, observed events cannot be interpreted as a difference caused by the imaging procedure. This is a distinction between describing what occurred and estimating a comparative effect.

The record further demonstrates the importance of keeping outcome categories distinct. The primary toxicity endpoint, serious adverse event counts, other adverse event counts, and deaths are separate entries. Treating one as a substitute for another would require definitions and analysis details that the registry does not report. The difference between the enrollment entry and the serious adverse event at-risk count also shows why denominators and analysis populations need explicit explanation.

Finally, a completed registry status and the presence of adverse event entries do not guarantee that all results or statistical methods are available. Without a reported primary result, confidence interval, missing-data approach, or analysis plan, the precision and completeness of the safety evidence cannot be assessed. These limitations are important for biostatisticians and clinical researchers interpreting registry-based evidence.

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 registry record does not report the primary toxicity count, despite defining the endpoint and its 2-year timeframe. This prevents a direct interpretation of the primary safety outcome. It also does not report a confidence interval or other measure of precision for that endpoint.

The enrollment entry is 42, whereas the serious adverse event group lists 36 at risk. The reason for this difference is not reported in the registry record. The analysis populations, endpoint-specific denominators, completeness of follow-up, and handling of missing data are also not reported. Consequently, the serious adverse event count cannot be assumed to use the same population as the primary endpoint.

The study is single-group, with no masking and no randomized comparison. This limits causal interpretation and prevents a direct estimate of an outcome difference versus another imaging approach. The record describes a change in serial scans and blood draws between groups but does not give group-specific results or the decision criteria behind that change.

The registry lists 31 deaths, but their timing, causes, attribution, and analysis context are not reported. The serious event terms are listed with percentages, but event-level detail, overlap between terms, and attribution are not described. The statistical analysis plan, sample-size justification, interim analyses, multiplicity approach, and prespecified analysis populations are not reported in the registry record. These omissions limit interpretation of completeness, uncertainty, and the scope of conclusions that can be drawn.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: PET Imaging With 89Zr-DFO-Trastuzumab in Esophagogastric Cancer — NCT02023996.
• Registry record last updated 2024-12-10; status last verified 2023-06.
• Results first posted 2024-12-10.
• 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

NCT02023996 is a completed pilot study of PET imaging with 89Zr-DFO-trastuzumab in esophagogastric cancer, sponsored by Memorial Sloan Kettering Cancer Center. The registry lists a single-group design, no masking, allocation as NA, and enrollment of 42. The primary outcome is the number of participants experiencing toxicity over 2 years, assessed using CTCAE v4.0. The primary outcome result is not reported in the registry record.

The serious adverse event listing reports 2 affected participants among 36 at risk and names five terms, each listed at 2.8%. The record also lists 31 deaths, without reporting their timing or context. Biologic half-time is named as a secondary outcome. The record describes an initial group intended to inform scan timing, blood persistence, and tolerability, and says serial scans and blood draws were no longer needed for Group 2 based on what had been learned. Statistical analysis details, missing-data handling, and the relationship between the enrollment and at-risk counts are not reported in the registry record.