MSG Use With 18F-DCFPyL PET/CT Imaging: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for MSG Use With 18F-DCFPyL PET/CT Imaging (NCT03693742), a randomized na study. The primary outcome is Salivary Gland Maximal Standardized Uptake Values Corrected for Lean Body Mass (SULmax) for 18F-DCFPyL.

2. Clinical Question

The study addressed a measurement question about radiotracer accumulation, rather than a clinical treatment outcome. The registry background explains that 18F-DCFPyL binds to prostate-specific membrane antigen and that uptake can also occur in salivary glands and kidneys. The proposed comparison was whether the MSG-containing drink was associated with a change in uptake in these organs.

The crossover format means the trial compared two scan conditions within the study, with the order described as variable. The posted primary group summaries report mean salivary-gland uptake for the MSG and placebo conditions. They do not report participant-level measurements or a detailed description of how the two measurements were paired in the analysis. The registry record does not report a clinical outcome such as dry mouth, treatment discontinuation, or tissue damage as the primary endpoint.

3. Trial Design

The registry lists this study as randomized, triple-masked, and crossover, with phase recorded as not applicable. Its stated title concerns MSG use with 18F-DCFPyL PET/CT imaging; the official title describes evaluation of MSG to reduce salivary-gland and renal accumulation of PSMA-binding radiopharmaceuticals. The sponsor was the British Columbia Cancer Agency.

The registry reports enrollment of 10 and status as completed. The study start date was 2019-11-04, and primary completion was 2019-12-12. The record lists prostate cancer, metastatic prostate cancer, and prostatic neoplasm among the conditions. The reported arm summaries each include 10 observations, one for the MSG-drink scan and one for the placebo-drink scan. Because the design is crossover, these arm summaries should not be read as evidence that the two conditions involved separate groups of participants.

For the MSG condition, food-grade MSG was dissolved in low-sodium tomato juice and administered orally before 18F-DCFPyL. For the placebo condition, regular tomato juice was administered before 18F-DCFPyL. The primary timeframe is described as a scan with MSG and, 3-7 days later, a scan with placebo, or the reverse sequence. The registry does not report the randomization procedure, the masking roles, the exact sequence allocation, or additional details about the scan protocol.

The primary efficacy population was defined as participants who received at least one dose of each intervention and completed all study visits. Although the record gives that definition, it does not report how many participants met it or provide a participant-flow account. The original sample-size rationale, trial-specific power assumptions, and detailed statistical analysis plan are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: 10 of 10 participants were randomized.

Overall Study

Analysis population for the primary outcome, as defined in the registry: All participants who received at least one dose of each intervention and completed all study visits were included in the efficacy analysis.

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 Salivary Gland Maximal Standardized Uptake Values Corrected for Lean Body Mass (SULmax) for 18F-DCFPyL, measured over scan with MSG and 3-7 days later, scan with Placebo (or vice versa).

The primary endpoint was salivary-gland maximal standardized uptake value corrected for lean body mass, or SULmax, for 18F-DCFPyL. The registry describes drawing regions of interest around the salivary glands using a standardized contouring method, measuring SULmax, and using the average SULmax in the organs for analysis. The primary outcome is continuous, and the posted group results are means with standard deviations.

This measurement was chosen to quantify radiotracer accumulation in salivary tissue. The registry’s rationale is that 18F-DCFPyL targets PSMA, while uptake can also occur in salivary glands and kidneys. In this study, the endpoint therefore captures imaging uptake under the two drink conditions. It does not directly measure symptoms, tissue injury, cancer response, or whether a participant continued or stopped treatment.

For the MSG-drink condition, the posted mean was 9.9 SULmax, with a standard deviation of 4.8. For the placebo-drink condition, the mean was 15.1 SULmax, with a standard deviation of 6.2. Those group summaries describe the observed measurements; interpreting their difference requires attention to the crossover design and to the analysis reported by the sponsor. The registry does not report a detailed account of measurement reliability or a clinically meaningful threshold for SULmax.

7. Results Posted in the Registry

• 18F-DCFPyL PET/CT Scan With MSG Drink: mean 9.90 versus 15.10 on control; difference -5.20 (95% CI -10.06 to -0.34), standardized effect d = -0.94; z-test p = 0.036.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Renal Maximal Standardized Uptake Values Corrected for Lean Body Mass (SULmax) for 18F-DCFPyL

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • 18F-DCFPyL PET/CT Scan With MSG Drink: mean 27.40 versus 37.50 on control; difference -10.10 (95% CI -17.85 to -2.35), standardized effect d = -1.14; z-test p = 0.011.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for 18F-DCFPyL PET/CT Scan With MSG Drink than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The posted renal endpoint shows a pattern in the same direction as the primary endpoint: mean SULmax is lower for the MSG-drink scan than for the placebo-drink scan. Its unadjusted recalculation also estimates a negative MSG-minus-placebo mean difference. This directional consistency is relevant context for the primary imaging result, but it does not independently validate the primary finding or establish a clinical outcome.

The registry also lists tumour SULmax and the number of participants with tomato-juice-related adverse events assessed by abnormal vital-sign measurement as secondary outcomes. Outcome-level results for tumour uptake and that specific vital-sign outcome are not reported in the registry record. The general adverse-event group figures are described separately and should not be substituted for a complete result on the named secondary endpoint.

Unadjusted secondary analyses carry less weight when the analysis plan and multiplicity handling are not reported. General: when several outcomes are tested, the probability of finding at least one apparently strong result can increase. Whether and how that issue was addressed depends on the planned analysis strategy. The registry record does not report the multiplicity procedure, a full endpoint hierarchy, or the status of each secondary analysis as prespecified or exploratory.

The secondary results should therefore be interpreted as supporting context rather than as a collection of independent confirmatory claims. The renal uptake summaries are directionally consistent with the primary summaries. The other listed secondary outcomes cannot be evaluated from outcome-level results in the registry record. Taken together, the available secondary information does not establish effects on tumour uptake or on the specified vital-sign outcome.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Renal Maximal Standardized Uptake Values Corrected for Lean Body Mass (SULmax) for 18F-DCFPyL
• Tumour Maximal Standardized Uptake Values Corrected for Lean Body Mass (SULmax) for 18F-DCFPyL
• Number of Participants With Tomato Juice (Containing Either MSG or Placebo) Related Adverse Events as Assessed by Abnormal Vital Sign Measurement.

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is a continuous measurement: salivary-gland SULmax. The registry reports a mean and standard deviation for each scan condition, an unadjusted recalculation based on those summaries, and a sponsor-reported mixed-model analysis. These are related but distinct statistical descriptions of the same primary comparison. General statistical explanations below clarify what each type of result can and cannot convey.

What does a mean describe?

General: A mean is an average that summarizes the central level of a continuous measurement. Here, the posted means describe SULmax for the MSG-drink and placebo-drink scan conditions. The means do not show how every participant’s measurements changed. A group mean can be lower even when some individual measurements do not follow that pattern.

The standard deviations describe spread around each group mean. The posted standard deviations are 4.8 for MSG and 6.2 for placebo. General: a larger standard deviation indicates more variation in measurements around the mean, but it does not reveal the shape of the distribution, identify outliers, or show which participants had higher or lower measurements under both conditions.

What does the mean difference describe?

The unadjusted recalculation expresses the contrast as the MSG mean minus the placebo mean. Its estimate is -5.2 SULmax. A negative sign means the MSG-condition mean is lower than the placebo-condition mean in this contrast. General: a difference is expressed in the outcome’s units, which makes its scale interpretable alongside the measurement itself. It is not a percentage change, and it is not a direct measure of clinical importance.

The recalculation is based on posted summary statistics. It is not the sponsor’s model-based analysis. The trial is crossover, while the posted summaries do not provide paired measurements or the within-participant covariance. General: when measurements are paired, their correlation affects the uncertainty of the within-person contrast. Without the paired data or covariance, a summary-statistics recalculation cannot recover all the information used by a paired analysis or mixed model.

What does a p-value tell the reader?

General: A p-value describes how compatible the observed data are with a specified null hypothesis, under the assumptions of the statistical method. It is not the probability that the null hypothesis is true, and it does not measure the magnitude or clinical importance of an effect. A smaller p-value is not a substitute for an estimate and its uncertainty.

The unadjusted recalculation gives p = 0.036. The sponsor reports a mixed-model superiority analysis with p < 0.001. Because the reported analyses differ, the sponsor’s own analysis takes precedence. The registry record does not provide the sponsor’s model estimate or confidence interval, nor enough model details to reproduce its result. The unadjusted p-value should therefore be read as a separate calculation from the posted group summaries, not as a competing reconstruction of the sponsor’s analysis.

Why can over-dispersion matter?

General: In count outcomes, over-dispersion means that variability exceeds what a simple model assumes. It can make standard errors too small if the model does not account for the extra variation. The primary endpoint in this trial is continuous SULmax, not a count outcome, so over-dispersion is not the central issue for interpreting this comparison. The registry does not report a count-model analysis for the primary endpoint.

What does the mixed model add?

General: A mixed model can represent different sources of variation and can be useful for repeated measurements or clustered observations. In a crossover study, a model may account for the structure of repeated measurements, depending on how it is specified. The registry identifies the sponsor’s method as mixed models analysis, but does not report the model formula, included effects, covariance structure, or handling of order and period. Those details cannot be inferred from the method label alone.

The sponsor classifies its reported analysis as a superiority analysis. General: a superiority test evaluates whether the data support a difference in a specified direction or a difference between conditions, according to the prespecified test. The registry does not report the full hypotheses or the sponsor’s numerical estimate, so the result can be described only as the reported superiority analysis with p < 0.001.

How should multiple outcomes be considered?

General: When several endpoints or analyses are tested, the chance of at least one apparently notable result can increase. Multiplicity procedures can adjust interpretation or testing thresholds, but their appropriateness depends on the planned outcome hierarchy and analysis plan. The registry record does not report a multiplicity adjustment or a complete hierarchy for the secondary outcomes. The posted unadjusted recalculations should therefore not be treated as multiplicity-adjusted confirmatory findings.

The primary endpoint has a stated role, while the registry also lists renal uptake, tumour uptake, and tomato-juice-related adverse events among secondary measures. The renal summary includes an unadjusted recalculation, but the tumour and adverse-event secondary outcome estimates are not reported in the registry record. The information available does not establish how many analyses were planned, which were prespecified, or whether any adjustment was used.

11. Confidence Intervals and Precision

The unadjusted recalculation for the primary endpoint estimates a mean difference of -5.2 SULmax, MSG minus placebo. Its reported confidence interval has both bounds below zero, and the unadjusted p-value is 0.036. A confidence interval gives a range of estimates compatible with the data and the method’s assumptions. It conveys uncertainty around the estimated contrast; it is not a range that contains a known fixed percentage of individual participant measurements.

The posted group standard deviations, 4.8 for MSG and 6.2 for placebo, describe variability in the observed measurements. They are not confidence intervals and do not directly express the precision of the mean difference. General: precision depends on both variability and the amount of information available, as well as on the analysis and study design. In a crossover trial, the relationship between each participant’s two measurements can also affect the precision of a within-person contrast.

The summary-statistics recalculation cannot account for the unavailable paired measurements or their covariance. Its confidence interval is therefore not a reconstruction of the sponsor’s mixed-model uncertainty. The sponsor reports p < 0.001 but does not report a model estimate or confidence interval in the registry record. That leaves the sponsor’s effect size and model-based precision unavailable for independent reading.

The confidence interval for the recalculated contrast is compatible with a range of negative differences, not one exact value. Statistical uncertainty remains even though the interval does not include zero under this recalculation. The result should be read alongside the sponsor-reported analysis, the small reported study enrollment, the crossover design, and the absence of participant-level data and model details. A statistically detectable contrast does not by itself establish clinical importance.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm, not total event counts. They are illustrations based on the observed effect, not the trial’s own original sample-size design. The registry does not report the trial’s original sample-size justification or assumptions. The planning calculation assumes a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It considers detecting the stated fraction of the observed effect.

For each effect-size scenario, the 80% power column gives the illustrative number of participants per arm under which the calculation has an 80% chance of detecting that assumed effect if the assumptions hold. The 90% power column gives the corresponding per-arm planning figure for a 90% chance under those assumptions. These are planning concepts, not guarantees about what a future study would detect.

The rows describe planning for 100%, 75%, and 50% of the observed effect. For the primary endpoint, the reported figures are 18 and 24 participants per arm for planning at 100% of the observed effect; 32 and 43 for planning at 75%; and 72 and 96 for planning at 50%, for 80% and 90% power respectively. The renal endpoint has its own planning figures, based on its observed effect.

Smaller effects generally require more participants to detect under otherwise similar assumptions. This is not observed power: it is a planning illustration based on the observed effect, not a measure of the trial’s achieved power or a retrospective judgment of whether its result is valid. The registry record does not report that these calculations were used to design the trial.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -5.200; pooled standard deviation σ = 5.544.
2. n = 2 × (1.96 + 0.842)² × 5.544² / -5.200² = 17.8, rounded up to 18 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -5.2                      # observed difference in means
sigma <- 5.54436651025164                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(3693742)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 18 (80% power), 24 (90% power)
 75% of observed effect: n per arm = 32 (80% power), 43 (90% power)
 50% of observed effect: n per arm = 72 (80% power), 96 (90% power)
power.t.test: 18.9 
Simulated power at n = 18 per arm: 0.781 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The sponsor’s own primary analysis is reported as a mixed-model superiority analysis with p < 0.001. The registry does not report its numerical model estimate or confidence interval. The separate unadjusted recalculation from the posted group summaries estimates an MSG-minus-placebo mean difference of -5.2 SULmax, with p = 0.036.

These results are not interchangeable. The recalculation uses the posted means and standard deviations; it does not have the participant-level paired measurements or the within-participant covariance needed to reproduce a crossover mixed model. The sponsor’s result comes from the analysis identified in the registry as mixed models analysis. The exact model specification and its estimate are not reported in the registry record.

The reported discrepancy means the sponsor’s own analysis takes precedence. The recalculation can still provide a descriptive, unadjusted comparison of the posted group summaries, but it should not be presented as a correction to or replacement for the sponsor’s result. The difference between the reported p-values cannot be explained from the available record alone. Without the model details and underlying data, it is not possible to determine precisely which analytical choices account for the difference.

In reading the sponsor’s result, p < 0.001 conveys evidence against the null comparison under the sponsor’s model and its assumptions. It does not provide the size of the modeled effect or the precision of that estimate. Those would require the model estimate and an interval, neither of which is reported in the registry record.

15. Multiplicity, Missing Data and Analysis Populations

The registry defines the primary efficacy population as participants who received at least one dose of each intervention and completed all study visits. This definition indicates that the primary analysis was not described as including everyone enrolled regardless of intervention exposure or completion. The record does not report how many participants satisfied the definition, the number excluded from the efficacy analysis, or the reasons for exclusion.

Details about missing data are not reported in the registry record. The record does not describe whether any measurements or visits were missing, how missing outcomes were handled, whether imputation was used, or whether sensitivity analyses assessed the effect of missingness. These omissions limit assessment of how the analysis population and observed results relate to all enrolled participants.

The crossover design makes the accounting of both conditions and study visits relevant to interpretation. The record describes scans with MSG and placebo 3-7 days apart, in either order, but does not give a participant-flow account or explain how incomplete sequences or unavailable paired measurements were treated. It also does not report whether period or sequence effects were evaluated in the sponsor’s model.

Multiplicity is another uncertainty. The registry lists a primary endpoint and several secondary outcomes, and the record reports one sponsor analysis and unadjusted recalculations. The multiplicity adjustment, if any, is not reported in the registry record. Without that information, the unadjusted secondary comparisons should be considered exploratory or supportive rather than treated as adjusted confirmatory evidence. The record also does not report how many analyses were planned or whether there was a prespecified hierarchy governing interpretation.

The sponsor’s analysis method is identified as mixed models analysis, but the model specification and full statistical plan are not reported. The registry record does not state whether interim analyses were conducted, and no interim-analysis information is reported. These missing details do not negate the posted results, but they prevent a complete assessment of the analysis choices, missing-data assumptions, and control of false-positive findings.

16. 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 adverse-event record reports zero serious adverse events and zero deaths in each scan-condition group. It also reports zero other adverse events in each group. The record lists 10 participants at risk for serious adverse events and 10 at risk for other adverse events in each condition.

These figures describe the adverse-event entries recorded for the two conditions. They should not be interpreted as proof that no adverse effects are possible, or as a complete account of all potential harms. The trial reports a small enrolled population, and the registry record does not provide event narratives, severity details for non-serious events, or a fuller account of safety surveillance.

The listed secondary outcome concerning tomato-juice-related adverse events assessed by abnormal vital-sign measurement is not accompanied by a separate outcome-level result in the registry record. The general adverse-event counts do not establish what was measured or found for every component of that specific secondary endpoint. The reported zeros are therefore best read as the recorded event counts, within the stated groups and at-risk entries, rather than a broad conclusion about safety.

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

The results concern a specific imaging comparison: 18F-DCFPyL salivary-gland uptake measured as SULmax after an MSG-containing tomato juice drink versus regular tomato juice. The posted group means are lower for the MSG condition. The sponsor’s reported mixed-model analysis gives p < 0.001, while the unadjusted recalculation from posted summaries gives a mean difference of -5.2 SULmax and p = 0.036. Because the analyses differ, the sponsor’s own analysis takes precedence.

This finding is about an imaging measurement. The registry record does not report that the study measured whether MSG reduced dry mouth, prevented tissue damage, changed cancer outcomes, or enabled participants to continue treatment. Those effects cannot be inferred from a difference in SULmax alone. The registry background describes a rationale involving salivary-gland and kidney uptake, but a proposed rationale is not itself a demonstrated clinical outcome.

The available record also does not establish whether the observed difference is clinically meaningful. No clinically meaningful SULmax threshold is reported. The sponsor’s estimate and confidence interval are not reported, and the unadjusted recalculation does not account for the paired structure of the crossover data. The study’s size and the absence of detailed model and missing-data information further limit what can be concluded from the posted results.

The reasonable statistical reading is narrow: the registry reports lower average salivary-gland uptake in the MSG scan summaries and a sponsor-reported mixed-model superiority result. That supports a difference in the imaging measure under the study conditions, as analyzed by the sponsor. It does not establish the magnitude of a clinical benefit, predict an individual participant’s experience, or answer questions beyond the measured outcomes and reported analyses.

18. Why This Trial Matters Statistically

This trial is statistically interesting because its randomized crossover design compares two scan conditions within a study rather than describing only unrelated groups. In general, crossover studies can make within-participant comparisons informative because each participant can contribute measurements under more than one condition. At the same time, analysis needs to account appropriately for repeated measurements and the relationship between them.

The registry makes that distinction visible: it reports group means and standard deviations, an unadjusted recalculation, and a sponsor-reported mixed-model analysis. The recalculation gives a useful summary-scale contrast, but it cannot reconstruct the paired information or model details that are not reported. The sponsor’s p-value is therefore the primary reported inferential result, while the independent summary-statistics calculation serves as a separate descriptive check. The discrepancy highlights why an analysis method and its assumptions matter, particularly in a crossover trial.

The study also illustrates the difference between a biomarker-like imaging measure and a clinical outcome. SULmax quantifies radiotracer uptake, but the registry does not report a primary symptom or patient-outcome result. Statistical evidence about the imaging endpoint should not be expanded into claims about clinical consequences without such evidence.

Finally, the registry’s limited reporting of model details, missing-data handling, multiplicity, and the original sample-size rationale leaves important questions unanswered. These gaps matter because they shape how uncertainty and confirmatory strength should be assessed. The trial’s results can be read as evidence about an imaging contrast, while the available record does not support a broader claim about patient experience or treatment outcomes.

19. 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 posted enrollment is 10, and the efficacy population is defined by intervention exposure and completion of all study visits. The registry does not report how many participants met that definition or provide a flow of participants through the study. This makes it difficult to assess the relationship between enrollment and the primary analysis population.

The crossover design calls for attention to within-participant measurements, but participant-level paired values and the covariance between conditions are not reported. The sponsor’s analysis is identified as a mixed model, yet its specification, estimate, and confidence interval are absent. The unadjusted recalculation therefore cannot reproduce the sponsor’s result, and the reason for the discrepancy is not reported in the registry record.

The record does not describe missing-data procedures, sensitivity analyses, or how incomplete scan sequences were handled. It also does not report whether period or sequence effects were assessed. These omissions are relevant to a study in which conditions are scanned in either order and separated by 3-7 days.

The original sample-size justification, the trial-specific design assumptions, and any interim-analysis information are not reported. The available planning illustrations are based on observed effects and should not be mistaken for the trial’s original design basis. Multiplicity handling for the listed endpoints is also not reported, limiting the strength of unadjusted secondary comparisons.

Finally, the primary measure is an imaging uptake value, and the registry does not report a clinically meaningful threshold or primary symptom outcome. The results therefore have a narrow scope: they describe scan measurements and the reported statistical comparison, not clinical benefit, tissue effects, or longer-term outcomes.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: MSG Use With 18F-DCFPyL PET/CT Imaging — NCT03693742.
• Registry record last updated 2023-02-21; status last verified 2021-11.
• Results first posted 2021-02-12.
• 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.

23. Record Summary

NCT03693742, “MSG Use With 18F-DCFPyL PET/CT Imaging,” is listed as a completed randomized, triple-masked crossover study sponsored by the British Columbia Cancer Agency. The registry reports enrollment of 10, a start date of 2019-11-04, and primary completion on 2019-12-12.

The primary endpoint was salivary-gland SULmax for 18F-DCFPyL, comparing scans after MSG-containing tomato juice and placebo tomato juice. The posted means were 9.9 for MSG and 15.1 for placebo. The sponsor reported a mixed-model superiority analysis with p < 0.001; an unadjusted recalculation from the posted summaries estimated a mean difference of -5.2 and p = 0.036. Because the analyses differ, the sponsor’s own analysis takes precedence.

The registry also reports lower mean renal SULmax with MSG, but does not report outcome-level results for tumour uptake or the named vital-sign secondary endpoint. Serious adverse events, other adverse events, and deaths were recorded as zero in each condition group. Model details, the original sample-size rationale, and missing-data and multiplicity procedures are not reported in the registry record.