Sulfur Colloid SPECT/CT in Measuring Liver Function in Patients With Primary or Metastatic Liver Cancer Undergoing Radiation Therapy or Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Sulfur Colloid SPECT/CT in Measuring Liver Function in Patients With Primary or Metastatic Liver Cancer Undergoing Radiation Therapy or Surgery (NCT02881554), a na na study. The primary outcome is Longitudinal Changes in Liver Function as Measured by SC SPECT/CT Total Liver Function: Cohort A - Radiation.

2. Clinical Question

3. Trial Design

This is a pilot study of functional liver imaging in patients with primary or metastatic liver cancer receiving radiation therapy or surgery. The registry lists the study as single-group, with no allocation and no masking. The two treatment cohorts are described as receiving radiation therapy or surgery according to standard of care; they are not randomized treatment arms and should not be interpreted as a controlled comparison.

The imaging procedure uses technetium Tc-99m sulfur colloid with SPECT/CT. The record states that patients have a total of 3 scans and identifies the first scan in both cohorts as routine medical care. It describes longitudinal measurement of liver function. The primary outcome concerns Cohort A, the radiation cohort, and the registry specifies that only participants with evaluable treatment scans were assessed for it. The record also lists secondary outcomes for Cohort B, the surgery cohort, including functional liver volume, liver-to-spleen mean, and total liver function.

The study phase is listed as NA, and its status is terminated. The registry lists enrollment as 41. It does not report the reason for termination, whether enrollment reached a planned target, or the number of participants with complete imaging at each assessment. The record also does not report a detailed protocol for scan timing beyond the stated primary-outcome time points, or a detailed statistical analysis plan. The design therefore supports a description of the imaging measurements in the specified study populations, but not a causal comparison of radiation therapy with surgery.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Only participants in Cohort A with evaluable treatment scans were assessed for this outcome.

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 Longitudinal Changes in Liver Function as Measured by SC SPECT/CT Total Liver Function: Cohort A - Radiation, measured over Baseline, mid-treatment at 2 weeks, and post-treatment at 1 month.

The primary endpoint is total liver function (TLF), measured as a ratio. The registry defines TLF as the product of the functional liver volume (FLV) ratio and the liver-to-spleen (L/S) mean ratio. Because it is a product of ratios, the endpoint is unitless. The record states that a higher TLF ratio reflects higher liver function.

The endpoint is intended to combine information about the amount of liver volume classified as functional and the liver-to-spleen mean measurement. In general, combining these components can represent more than either component alone, although the registry record does not report validation evidence or explain how the measure relates to clinical outcomes. It describes sulfur colloid SPECT/CT as a way to measure normal liver tissue before, during, and after treatment.

The primary outcome tracks TLF in Cohort A, the radiation cohort, at baseline, mid-treatment at 2 weeks, and post-treatment at 1 month. Only participants with evaluable treatment scans were assessed. The registry specifies medians, full-range dispersion, and Wilcoxon (Mann-Whitney) tests for estimating median differences. Numerical TLF values, estimated changes, and uncertainty intervals are not reported in the registry record, so the amount and precision of any observed change cannot be determined from it.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a longitudinal measurement, meaning the same general construct is assessed at multiple scheduled times. The registry specifies baseline, mid-treatment at 2 weeks, and post-treatment at 1 month. In general, repeated measurements can describe the pattern of change over time, but observations from the same person are related. Analysis should account for that dependence when estimating uncertainty. The registry record does not describe a repeated-measures model or explain how dependence was handled.

What does the Wilcoxon (Mann-Whitney) label mean?

The registry states that median differences were estimated using Wilcoxon (Mann-Whitney) tests. In general, this is a rank-based method: observations are ordered, and the analysis compares their ranks rather than relying directly on a normal-distribution model for the raw measurements. It can be useful when data are skewed or when a distributional assumption for a parametric comparison is not appropriate.

As a general statistical point, the Mann-Whitney test is commonly used to compare independent groups. It does not automatically test a difference in medians under every possible distribution pattern; interpretation as a median comparison is most straightforward when the distributions have similar shapes. For paired or repeated measurements, methods that retain the within-person pairing may be appropriate. The registry record does not specify which assessment-time contrasts were tested or how the named test was applied to measurements collected longitudinally. It therefore does not provide enough detail to determine the exact estimand or verify that the test handled repeated observations as intended.

How should medians and full ranges be read?

A median describes the middle of an ordered set of observed values. It is less affected by extreme values than the arithmetic mean, which can be useful when measurements are asymmetric. The full range gives the lowest and highest observed values and conveys the total spread, but it does not show how densely observations fall between those endpoints. A range can also be sensitive to extreme observations. Neither statistic alone describes uncertainty in an estimated change. The registry record does not provide the primary outcome values or confidence intervals.

The endpoint itself is a product of two ratios: the functional liver volume ratio and the liver-to-spleen mean ratio. In general, a product can change because either component changes, or because both do. A reported change in the combined endpoint would not, by itself, identify which component drove it. Component-specific results could help explain that pattern, but the primary outcome description does not report those values.

What does an uncertainty interval add?

In general, a confidence interval gives a range of values compatible with the data and the assumptions of the analysis. It communicates precision as well as direction: a narrow interval indicates more precision than a wide interval, while an interval spanning values on different sides of a null value may leave the direction uncertain. A p-value addresses compatibility with a specified null model, not the size or clinical importance of an effect. The registry record does not report confidence intervals or p-values for the primary outcome, so neither significance nor precision can be assessed.

The study is not randomized and has no allocation to treatment groups. In general, nonrandomized cohorts can differ in health status, treatment selection, and other characteristics, so a contrast between them may reflect those differences as well as treatment. Here the registry frames radiation and surgery as separate standard-of-care cohorts, and the primary outcome is confined to the radiation cohort. The study design therefore does not provide a like-for-like controlled comparison of the treatments.

How should planning calculations be interpreted?

The record describes planning illustrations based on an observed effect, using 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 time-to-event calculations, the reported quantity is the total number of events, while other calculations refer to participants per arm. These are planning assumptions, not observations from participants and not evidence of achieved power. The record does not state that these assumptions were the trial's own design rationale. Because the study is listed as single-group and not randomized, a hypothetical equal-allocation comparison should not be mistaken for its actual design.

In general, a sample-size calculation depends on the assumed effect, variability, significance threshold, power target, allocation, and analysis. If assumptions differ from the eventual study or the actual data, the calculation may not describe the precision achieved. The registry record does not report a sample-size justification for this pilot or enough primary-outcome results to evaluate such a calculation against the observed data.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 7 outcome measures and 7 analyses. The primary outcome is TLF in Cohort A, the radiation cohort. Listed secondary outcomes include functional liver volume, liver-to-spleen mean, and total liver function in Cohort B, the surgery cohort. When multiple outcomes or time-point comparisons are examined, the chance of at least one apparently unusual result can increase. In general, a prespecified testing hierarchy or multiplicity adjustment can help control that issue, but the registry record does not report whether one was used.

The record does not specify all planned contrasts among baseline, mid-treatment at 2 weeks, and post-treatment at 1 month. It also does not report whether analyses were prespecified, whether additional analyses were conducted, or how any repeated testing was handled. The seven listed analyses alone do not establish how many statistical tests were performed or which results were treated as primary for inference.

The stated primary-outcome population includes only Cohort A participants with evaluable treatment scans. The registry record does not report how many participants had missing or unevaluable scans, why data were unavailable, or whether missing values were imputed, excluded, or handled by another method. It does not describe the analysis population beyond the evaluability statement, or give rules for inclusion at each time point. These omissions limit assessment of possible selection bias and of whether participants with incomplete data differed from those with evaluable scans.

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.

The registry reports serious adverse events for the radiation and surgery cohorts separately. For Cohort A, 36 participants were listed as at risk for serious adverse events, and 0 were reported as affected. For Cohort B, 3 participants were listed as at risk, and 0 were reported as affected. Other adverse events were also listed as 0 among 36 at risk in Cohort A and 0 among 3 at risk in Cohort B. The registry lists deaths of 22 in Cohort A and 1 in Cohort B.

These are descriptive safety counts, not a randomized comparison. The cohorts differ in treatment context, and the registry does not report exposure time, event-monitoring duration, event attribution, or the criteria used for the reported categories. The death counts should not be interpreted as treatment-related deaths; the record does not state their causes or relationship to treatment. Zero reported affected participants for an event category does not establish that the treatment has no risk, particularly when the observation period and completeness of follow-up are not reported. The registry record also does not list serious adverse-event terms.

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

The central statistical contribution of this study is its focus on measuring liver function longitudinally with sulfur colloid SPECT/CT in patients undergoing liver-directed treatment. The primary endpoint combines the functional liver volume ratio and liver-to-spleen mean ratio into a unitless TLF ratio. The record states that higher values reflect higher liver function, and identifies assessment at baseline, mid-treatment at 2 weeks, and post-treatment at 1 month.

That measurement framework does not establish what the observed change was. The registry record does not report numerical primary-outcome results, variability, confidence intervals, or test results. Readers therefore cannot determine from the registry record whether TLF changed, how large a change was, or how precisely it was estimated. The stated analysis method alone is not a result.

Nor does a longitudinal change in the radiation cohort establish that radiation caused the change. A single-group design cannot separate treatment-associated change from other changes over time. The surgery cohort is not a randomized control group; its treatment context and listed outcomes differ. The study also does not report whether TLF is associated with later clinical outcomes or whether scan findings altered treatment decisions.

The study's pilot status is relevant to interpretation: the stated aim is to examine functional imaging in these treatment settings, not to establish a definitive treatment comparison. The registry record does not report the reason for termination, the number of participants with complete follow-up, or a detailed analysis plan. Thus, the most defensible reading is that the record describes a measurement question and a planned analysis approach, while leaving the quantitative findings and several interpretive details unreported.

The findings, as recorded, cannot establish diagnostic accuracy, clinical utility, or comparative treatment effectiveness. Those are separate questions that require suitable outcome data and analysis. No treatment recommendation follows from the information in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically notable for treating liver function as a longitudinal imaging measure rather than relying only on a single assessment. Serial measurements can, in principle, describe whether a functional imaging marker changes during and after treatment. That is relevant to research on liver-directed treatment because anatomy alone may not capture functional tissue; the registry's stated rationale is that sulfur colloid SPECT/CT may measure normal liver tissue around treatment.

The endpoint also illustrates a measurement choice with interpretive consequences. TLF combines a functional-volume component and a liver-to-spleen mean component. A single composite value may provide a concise summary, but a change in the composite can arise through changes in either component. Component results and clear analysis of repeated measurements would help readers understand what underlies a pattern.

The design highlights why a pilot cohort should not be read as a treatment comparison. Radiation and surgery are delivered in separate standard-of-care cohorts, without random allocation. Statistical differences between such groups, if reported, would not by themselves identify a treatment effect. The primary focus is Cohort A, while the listed secondary measurements concern Cohort B.

Finally, the record makes the distinction between an analysis plan and evidence especially important. It names medians, full-range dispersion, and a Wilcoxon (Mann-Whitney) approach, but does not report primary numerical results or enough detail to evaluate the handling of longitudinal dependence and missing scans. The statistical question is meaningful, but the registry record does not contain the result needed to judge the size or precision of the observed changes.

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 outcome values, estimated median differences, ranges, p-values, or confidence intervals. This prevents assessment of the direction, magnitude, and precision of change in TLF. The record identifies Wilcoxon (Mann-Whitney) tests but does not specify the exact time-point contrasts or how the analysis accounts for repeated measurements from the same participants.

The primary outcome population is limited to Cohort A participants with evaluable treatment scans. The number of participants with evaluable data at each time point, reasons for missing or unevaluable scans, and missing-data methods are not reported in the registry record. This leaves uncertainty about the completeness and representativeness of the analyzed measurements.

The single-group, nonrandomized design does not provide a like-for-like comparison between radiation and surgery. The registry does not report a concurrent untreated control or an analysis that can isolate treatment effects from changes over time and other factors. The record also does not report whether the imaging measure was validated against clinical outcomes, how scan results influenced care, or whether changes in TLF corresponded to patient outcomes.

The status is terminated, but the reason for termination is not reported in the registry record. A detailed protocol, statistical analysis plan, multiplicity approach, and sample-size justification are also not reported. These limitations mean that the record can describe the study's measurement focus and stated analysis method, but cannot support a firm interpretation of its quantitative findings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Sulfur Colloid SPECT/CT in Measuring Liver Function in Patients With Primary or Metastatic Liver Cancer Undergoing Radiation Therapy or Surgery — NCT02881554.
• Registry record last updated 2025-10-29; status last verified 2025-10.
• Results first posted 2025-10-29.
• 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

NCT02881554 is a terminated pilot study sponsored by the University of Washington. It evaluates technetium Tc-99m sulfur colloid SPECT/CT imaging in patients with primary or metastatic liver cancer receiving radiation therapy or surgery. The study is listed as single-group, with no allocation and no masking. The registry lists enrollment as 41 and phase as NA.

The primary outcome is longitudinal TLF in the radiation cohort, defined as the product of the functional liver volume ratio and liver-to-spleen mean ratio. Assessments are specified at baseline, mid-treatment at 2 weeks, and post-treatment at 1 month. The registry record describes median differences and Wilcoxon (Mann-Whitney) tests but does not report numerical primary-outcome results. It also does not report the reason for termination, detailed missing-data methods, or a complete statistical analysis plan.