Comparison Study of PET/CT or PET/MRI Imaging to Magnetic Resonance Imaging (MRI) Alone in Men With Prostate Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparison Study of PET/CT or PET/MRI Imaging to Magnetic Resonance Imaging (MRI) Alone in Men With Prostate Cancer (NCT03439033), a non-randomized phase 2 study. The primary outcome is Number of Subjects With Pathologic Lesions Detected by PSMA PET and PET/CT Compared to MP MRI.

2. Clinical Question

This question is about detection by imaging, not about a treatment effect or a participant health outcome. The registry record describes scans after administration of the study drug, with the primary measure assessed at each visit. It does not report enough outcome data to determine how often the imaging approaches identified lesions or how their detection compared.

3. Trial Design

This was a phase 2, non-randomized, parallel-group study with no masking. The registry record lists enrollment as 273. It names Weill Medical College of Cornell University as the sponsor. The study start date is 2018-04-03, and the primary completion date is 2021-05-05. Its status is listed as terminated; the reason for termination is not reported in the registry record.

The comparison concerned MRI alone and imaging using Gallium-68 labeled PSMA-HBED-CC with PET/MRI or PET/CT. The listed intervention groups include PET/MRI, multiple PET/MRI, and PET/CT. The arm descriptions say the PET/MRI group had one visit, while the multiple PET/MRI group was invited for two visits within two years, with the second visit optional. The PET/CT description specifies a scan at one visit. The brief summary says PET/CT could be used for potential subjects unable to undergo MRI. Further details of the PET/CT arm description are incomplete in the registry record.

The primary outcome timeframe is described as immediately after study-drug administration at each visit, approximately 2-3 hours, with up to two visits within 2 years or less. This gives the planned timing of assessment, but the record does not report how many participants completed each scan, the number of visits actually conducted, or the comparative primary-outcome findings.

Non-randomized allocation is important to interpretation. When participants are not assigned at random, differences between imaging groups may reflect who entered each group as well as the imaging approach. The registry record does not report an adjustment strategy that would address such differences. The groups therefore cannot be read as a like-for-like randomized control comparison.

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

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 Subjects With Pathologic Lesions Detected by PSMA PET and PET/CT Compared to MP MRI, measured over At each visit, immediately after administration of the study drug, approximately 2-3 hours; with up to two visits within 2 years or less.

The primary endpoint is the number of participants with pathologic lesions detected by PSMA PET and PET/CT compared with multiparametric MRI. Its unit is participants, and the measure is a count of participants with an event. The registry record defines a scan as positive when the reader's clinical interpretation was suspicious. It does not provide a separate objective positivity threshold or a reference standard in the available description.

A participant-level detection count can describe how many people had a scan interpreted as positive under the study's reading approach. It is not the same quantity as the number of lesions: one participant may have more than one lesion, while this primary measure counts participants. The registry also lists a secondary outcome concerning the number of pathological lesions detected by PSMA PET/MRI and PET/CT compared with multiparametric MRI by anatomical region. These are distinct kinds of measurement and should not be conflated.

Imaging detection is useful for comparing what scans identify, but interpretation depends on how positivity is defined and on the population examined. The record's description relies on the reader's clinical judgment. The registry record does not report comparative counts, sensitivity estimates, uncertainty intervals, or enough information about lesion verification to assess diagnostic accuracy. The stated endpoint therefore identifies the intended question, while the absence of posted outcome results prevents a conclusion about the observed comparison.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods help connect a study question to an estimate and clarify how much uncertainty surrounds that estimate. In this study, the primary endpoint is a count of participants with a positive scan, with positivity based on the reader's clinical judgment. The registry record does not report the comparative count values or the statistical method used to analyze them. The explanations below are general; they do not assert that any particular method was used for this study.

What does a participant count measure?

A count records how many participants meet a defined event condition. Here, the event condition is having a scan interpreted as positive for pathologic lesions. A count is tied to the number of people assessed and to the definition of a positive result. Comparing raw counts without knowing how many participants in each group were actually assessed can be misleading. The registry record lists enrollment as 273, but it does not report the analyzed group sizes or primary-outcome denominators. The enrollment figure should not be mistaken for the number included in each outcome analysis.

Counts can also answer different questions depending on their unit. The primary endpoint uses participants, whereas the listed secondary outcome concerns the number of lesions detected by anatomical region. Those measures are not interchangeable. A participant-level outcome asks whether people had a positive scan; a lesion-level outcome concerns detected lesions. General statistical analyses of lesion counts may need to account for multiple lesions belonging to the same participant, because observations from one person may be related. The registry record does not report the analysis details needed to determine how the secondary outcome was handled.

What does uncertainty mean?

A confidence interval is a general way to express the uncertainty around an estimated effect. It gives a range of values compatible with the data and the method used, under the assumptions of that method. A narrow interval indicates greater precision than a wide interval, but an interval does not eliminate bias from study design or measurement. No confidence interval for the primary comparison is reported in the registry record. Without an estimate and its uncertainty, readers cannot assess the precision of the comparison.

A p-value, when used, addresses how compatible the observed data are with a specified null model and its assumptions. It is not the probability that the null hypothesis is true, nor does it describe the size or clinical importance of an effect. The registry record does not report a primary-outcome p-value or test. It is therefore not possible to characterize the result as statistically significant or not statistically significant.

Why does allocation matter to analysis?

In a randomized study, assignment by chance is intended to make comparison groups similar on average with respect to participant characteristics. In a non-randomized study, group membership may be related to clinical or practical factors. Those factors can also be associated with the chance that an image is positive. Statistical adjustment can sometimes address measured differences, but it cannot guarantee control of unmeasured differences. The registry record labels this comparison non-randomized and explicitly notes that the arms are not a like-for-like control comparison. It does not report adjusted estimates or the covariates, if any, used in an analysis.

In general, an unadjusted comparison describes the observed groups as they are, while an adjusted comparison attempts to compare groups after accounting for specified factors. Each depends on assumptions and on the quality and completeness of the data. Neither approach can be identified as the method for this study from the registry record, because its statistical analysis details are not reported.

How should planning illustrations be understood?

The record describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. For non-time-to-event outcomes, those illustrations are described as participants per arm; for time-to-event outcomes, they are described as total events. These are planning assumptions, not findings about participants in this study. Any resulting sample-size illustration is not observed power and does not substitute for the actual effect estimate, analysis, or uncertainty interval.

In general, a sample-size calculation asks how much information would be needed under chosen assumptions to detect a specified effect with a chosen probability. It depends on the assumed effect, variability, allocation, statistical test, and other design choices. A calculation based on an observed effect is especially dependent on that effect estimate. The registry record does not report the calculation outputs or the trial's own design justification. The stated planning description should therefore be read only as an illustration, not as evidence that the study had a particular achieved power or that its design was based on those assumptions.

What is not available for a full statistical appraisal?

The registry record does not report the primary comparative result, an analysis population, the number assessed in each group, missing-data methods, a prespecified statistical analysis plan, or details of adjustments. It also does not report whether analyses were interim or how the reader-based interpretation was standardized. These details matter because they determine which observations contribute to an estimate and how the estimate should be interpreted. Without them, a statistical reconstruction of the primary comparison is not possible from the registry record.

General principles can explain what an analysis might need to address, but they cannot fill gaps in a study report. The available record supports describing the endpoint and design, not asserting that a particular model, correction, or testing procedure was used.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("PSMA PET/MRI and PET/CT Scan", "MRI Scan")
n      <- c(109, 109)
events <- c(63, 37)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  PSMA PET/MRI and PET/CT Scan  109  63  57.8  48.0  67.2  48.4  66.6  48.4  66.7
ARM  MRI Scan  109  37  33.9  25.1  43.6  25.7  43.2  25.7  43.3

11. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when a study examines more than one outcome, comparison, subgroup, time point, or analysis. In general, conducting multiple statistical tests can increase the chance of finding at least one apparently notable result by chance. A study may address this through a prespecified hierarchy, adjustment procedure, or a clear distinction between primary and exploratory analyses. The registry record lists three outcome measures and one analysis, but it does not report a multiplicity procedure or explain how the outcomes were prioritized in analysis. The count of analyses alone does not identify what was tested or how multiplicity was handled.

The primary endpoint is described as a participant count, and the record also lists a lesion count by anatomical region as a secondary outcome. It does not provide outcome results or clarify whether the secondary measures were analyzed separately, combined, or treated as exploratory. A reader therefore cannot determine from the registry record whether any reported statistical evidence, if it existed elsewhere, accounted for multiple comparisons.

Missing-data handling is also not reported in the registry record. The available information does not state how participants with absent scans, incomplete visits, or unevaluable images were handled. It does not report the number of participants included in each primary analysis or the denominator for each comparison. These omissions matter because the interpretation of a count depends on who was assessed and how unavailable observations were treated.

The analysis population is not reported in the registry record. It is not possible to tell whether the primary analysis included all enrolled participants, only those who underwent imaging, or another defined group. The statistical analysis plan, including any planned interim analyses, is not reported in the registry record. No assumptions about those procedures can be made from the listed study status or the number of analyses.

12. 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.

The registry record lists safety counts by scan group. For PSMA PET/MRI Scan, the serious-adverse-event group lists 273 at risk and 0 affected; the other-adverse-event group also lists 273 at risk and 0 affected, with 0 deaths. For MRI Scan, the corresponding listed figures are 273 at risk and 0 affected for serious events, 273 at risk and 0 affected for other events, and 0 deaths. For PSMA PET/CT, the record lists 1 at risk and 0 affected in each event group, with 0 deaths. For PSMA Multiple PET/MRI, it lists 0 at risk and 0 affected in each event group, with 0 deaths.

These are the registry's recorded counts for the named groups and event categories. A zero affected count means no affected participants are listed in that entry; it does not establish that every possible adverse event was absent or that all enrolled participants contributed safety information. The listed at-risk counts differ by group, and the record does not explain the analysis populations or exposure accounting behind them. The group entries should not be added together to infer a unique participant total. The registry record lists no top serious-event terms.

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

The record establishes that a phase 2, non-randomized imaging comparison was registered, identifies its imaging approaches, and defines a reader-based primary measure of participant-level lesion detection. It also gives the study status, enrollment, timing, and safety counts by scan group. These details describe the question and the recorded study framework.

They do not establish whether PSMA PET/MRI or PET/CT detected more lesions or more participants with suspicious findings than MRI alone. The registry record does not report primary-outcome counts, an estimated comparison, a confidence interval, or a statistical test result. The stated hypothesis about greater sensitivity is not an observed finding. Without results, neither the direction nor the magnitude nor the precision of the comparison can be determined.

The design further limits causal interpretation. Allocation was non-randomized, so any difference between groups could reflect differences in who received each imaging approach as well as differences between the scans. The registry record itself cautions that the arms are not a like-for-like control comparison. No statistical adjustment details are reported that would allow the reader to evaluate whether group differences were addressed.

The endpoint is based on whether a reader judged a scan suspicious. This measure describes interpretation under the stated rule, but the record does not report a reference standard, reader agreement, or the specific methods used to establish diagnostic accuracy. A positive scan count should not be taken as a complete measure of sensitivity or as evidence about clinical outcomes.

The safety entries record zero affected participants for the listed serious and other adverse-event categories and zero deaths in the groups shown. They should be read as registry entries rather than as proof that no safety events of any kind occurred. Taken together, the available information supports a description of the study's design and recorded counts, but not a conclusion about comparative diagnostic performance or clinical benefit.

14. Why This Trial Matters Statistically

This study raises a statistically important comparison: whether imaging with a PSMA tracer and PET can identify pathologic lesions differently from MRI alone. Diagnostic comparisons can be difficult to interpret because an observed positive scan is not automatically equivalent to a confirmed lesion, and because the chosen unit of analysis matters. This record distinguishes a participant-level detection count from a secondary lesion count by anatomical region, making clear that those outcomes answer different questions.

The study also illustrates why design labels are central to interpretation. A non-randomized comparison can be affected by differences in the people who undergo each imaging approach. Such differences can complicate interpretation even when a statistical analysis is performed. The registry record explicitly notes that the arms are not a like-for-like control comparison, a caution that should travel with any reading of the intended comparison.

Outcome definition is another key issue. Here, scan positivity depends on the reader's clinical judgment. This makes the assessment rule important, while details about standardization, reader agreement, or independent confirmation are not reported in the registry record. These are not minor technicalities: they affect what a positive count can represent and how far it can be generalized.

Finally, the registry record demonstrates the distinction between a registered research question and a reported result. It documents a hypothesis and a planned endpoint, but does not include the comparative outcome values needed to evaluate that hypothesis. Statistical interpretation requires estimates and their uncertainty, not just a design and a stated expectation. The available information therefore makes the limits of inference as important as the original question.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The principal limitation for interpreting the comparison is that the registry record does not report the primary-outcome results. There are no comparative participant counts, effect estimate, confidence interval, or primary statistical test result in the available information. The study hypothesis cannot be assessed from the record alone.

The allocation was non-randomized, and the record warns that the arms are not a like-for-like control comparison. It does not report whether measured group differences were adjusted for or what variables might have been considered. Unmeasured differences could remain even if adjustment had been used; the record does not provide details to assess that possibility.

The primary outcome relies on a reader's clinical judgment that a scan was suspicious. The registry record does not report a reference standard for confirming pathologic lesions, reader masking, agreement between readers, or a standardized threshold beyond the description of clinical suspicion. It also does not report the primary analysis population, group-specific outcome denominators, or the handling of missing or unevaluable scans.

The registry lists three outcome measures and one analysis, but does not explain the statistical analysis plan or how multiplicity was addressed. The number of analyses does not reveal which comparisons were conducted or how their results were interpreted. The reason the study was terminated is not reported in the registry record, and the record does not state how termination affected enrollment, follow-up, or analysis.

The safety group entries have different at-risk counts, including a group with 0 at risk, and the record does not explain these denominators. The counts should therefore be interpreted only as listed, not as a complete account of exposure or all possible adverse events. These limitations leave the study's comparative findings and their precision unassessable from the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Comparison Study of PET/CT or PET/MRI Imaging to Magnetic Resonance Imaging (MRI) Alone in Men With Prostate Cancer — NCT03439033.
• Registry record last updated 2023-03-13; status last verified 2023-02.
• Results first posted 2023-03-13.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry record describes a phase 2, non-randomized, parallel-group imaging study with no masking, sponsored by Weill Medical College of Cornell University. Enrollment is listed as 273. The study began on 2018-04-03, reached primary completion on 2021-05-05, and is listed as terminated. The reason for termination is not reported in the registry record.

The intended comparison was MRI alone with PSMA PET/MRI or PET/CT using Gallium-68 labeled PSMA-HBED-CC. The primary endpoint counts participants with pathologic lesions detected, with scan positivity based on reader clinical judgment. Comparative primary-outcome results and their statistical uncertainty are not reported in the registry record. Safety entries list zero affected participants and zero deaths in the named groups, with the group-specific at-risk counts described in the record.