Lighting Intervention for Cancer-related Fatigue: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Lighting Intervention for Cancer-related Fatigue (NCT04827446), a randomized na study. The primary outcome is Change in Fatigue Assessed With Patient-Reported Outcomes Measurement Information System (PROMIS) Short Form (SF) Fatigue 4a.

2. Clinical Question

The trial addresses a question about a specific app-delivered lighting intervention and fatigue in cancer populations. Its primary endpoint is a between-arm comparison at the final assessment, rather than a change score calculated from the same four-item measure at baseline and follow-up. The registry record explains that a week-zero PROMIS Fatigue 4a measurement was unavailable, so the study used the final-week measure and planned to control for baseline fatigue using the one-item fatigue question from the pre-trial PROMIS Global Health survey.

Sleep disturbance, anxiety, depression, physical function, and overall health were also named as secondary outcomes. These outcomes broaden the scope beyond fatigue, but the registry record does not report their results. The central question can therefore be described from the registered assessment plan, while the size and precision of any observed difference between arms cannot be assessed from this record.

3. Trial Design

The registry record describes a completed, randomized, parallel-group trial of the SYNC app. Enrollment was 139. The brief summary says participants would be randomized 1:1 to the intervention app or a control app. The record identifies the study as single-masked, but does not identify which participants or study personnel were masked. It also does not describe the allocation sequence or how assignments were concealed.

The intervention arm received the full SYNC app with a light intervention and blue-light blocking glasses. The control arm received a placebo light intervention through the app and clear glasses. A wearable sensor is listed as an intervention item, but the record does not explain how it was used, whether it was used in both arms, or what information it collected. The trial is described as covering breast cancer, prostate cancer, and people who had undergone autologous HSCT.

The listed start date is 2021-07-15, and the primary completion date is 2023-03-09. The study status is completed. These dates describe the registry record’s study timeline; they do not establish when any particular participant was assessed. The phase is listed as NA.

The primary endpoint was PROMIS Fatigue 4a at week 11. The record says the primary analysis was intended to compare final-week fatigue between arms and assess the treatment effect while controlling for baseline fatigue with a one-item question from the pre-trial PROMIS Global Health survey. It does not report the final number analyzed in each arm, participant flow, deviations from the planned assessment, or the statistical results. The masking details, allocation procedures, and other protocol methods are also 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.

Overall Study

Reasons for not completing this period:

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 Change in Fatigue Assessed With Patient-Reported Outcomes Measurement Information System (PROMIS) Short Form (SF) Fatigue 4a, measured over 11 weeks.

The primary endpoint is fatigue measured with the Patient-Reported Outcomes Measurement Information System (PROMIS) Fatigue 4a Short Form. This is a four-item patient-reported measure, and the registry record identifies its unit as a score on a scale. The planned primary time point was the end of trial at week 11. The endpoint was intended to compare fatigue between the intervention and control arms.

The record explains why the primary assessment was not expressed as change from baseline on the same four-item measure: a PROMIS Fatigue 4a weekly measurement was not available at week zero. Instead, the planned analysis used the final-week Fatigue 4a assessment and adjusted for baseline fatigue using a separate one-item question from the pre-trial PROMIS Global Health survey. That item asked participants to rate their average fatigue over the past seven days. The one-item survey measure was scored from 0 (least fatigued) to 4 (most fatigued).

Using a patient-reported fatigue measure makes the endpoint directly relevant to the symptom the trial set out to assess. In general, a score can describe participants’ reported experience in a consistent format; interpretation depends on the measure’s scoring and on the size and precision of the estimated between-arm difference. The registry record does not report the observed scores, the estimated difference, or a confidence interval, so the endpoint’s results cannot be interpreted from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes random allocation to two parallel arms. In general, randomization is intended to make treatment assignment independent of participants’ characteristics, on average, so that a between-arm comparison can be interpreted as an estimate of the effect of assignment under the study conditions. Randomization does not guarantee that the arms are identical on every characteristic, and it does not resolve problems caused by missing outcome data, deviations from assigned treatment, or incomplete reporting. The record does not report the allocation sequence, concealment procedures, or participant flow.

What does the planned endpoint comparison estimate?

The primary endpoint was fatigue at week 11, measured with PROMIS Fatigue 4a. The registry description says the final-week assessment would be compared between arms. It also says the treatment effect would be assessed while controlling for baseline fatigue, measured with a one-item question from the pre-trial PROMIS Global Health survey. In general, baseline adjustment incorporates an initial measurement into the model used to compare groups at follow-up. It can account for baseline differences and may improve precision when the baseline measure is informative about the follow-up outcome. The record does not report the model’s full specification or the resulting estimate.

The record explicitly distinguishes the week-11 endpoint from a change-from-baseline score on PROMIS Fatigue 4a. Because the four-item weekly measure was not available at week zero, a change score based on that same instrument could not be calculated as described. The separate one-item baseline question was used for adjustment, not described as a week-zero Fatigue 4a score. These are different measures and should not be treated as interchangeable measurements of change.

Why might the analysis use generalized estimating equations?

The registry description names generalized estimating equations (GEE) as the method for controlling for baseline fatigue. In general, GEE is a regression approach used when observations may be correlated, such as repeated measurements from the same participant. It estimates average relationships across a population while accounting for within-participant dependence through a working correlation structure and an estimate of uncertainty. The exact role of GEE in this trial is not fully clear from the description, which refers to the treatment effect at week 11 while controlling for baseline fatigue. The record does not state the outcome distribution, link function, working correlation structure, variance estimator, covariates beyond baseline fatigue, or model diagnostics. Those details are not reported in the registry record.

Over-dispersion is a general concern when observed variability exceeds what a chosen model assumes. If it is present and not handled appropriately, standard errors and resulting uncertainty estimates may be misleading. Whether over-dispersion was relevant to this continuous fatigue score, how variability was assessed, and how uncertainty was estimated are not reported in the registry record. No specific claim about over-dispersion or model adequacy can be made for this analysis.

What information is needed to interpret an estimate?

A treatment-effect estimate would describe the size and direction of the modeled between-arm difference. Its confidence interval would show the precision of that estimate under the analysis assumptions. A p-value can address compatibility with a specified null hypothesis, but it cannot replace the effect estimate or its uncertainty. General interpretation should consider all three together and should also account for the score’s meaning and the study population. The registry record does not report an estimate, confidence interval, or p-value for the primary outcome.

The record lists a planning illustration approach using a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. Such calculations are planning illustrations, not observed power, and do not show what the trial actually achieved. The record does not provide the values needed to describe a particular illustration or a trial-specific sample-size justification. The assumptions for the original design are not reported in the registry record.

The record reports the outcome measure’s type as a mean of a continuous measure with standard deviation as its dispersion. In general, a mean summarizes the center of a numeric score distribution, while a standard deviation describes the spread of individual scores around the mean. Neither statistic is reported by arm for the primary endpoint in the registry record. Without the observed summaries and analysis output, no unadjusted recalculation or comparison can be interpreted.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary fatigue outcome and secondary outcomes for sleep disturbance, anxiety, depression, physical function, and overall health. It does not report a multiplicity plan, such as a testing hierarchy or adjustment to account for examining several outcomes. In general, conducting multiple tests can increase the chance of obtaining at least one apparently notable finding by chance. Whether that concern affected any conclusions cannot be assessed because no outcome results or statistical analysis are reported.

Missing-data methods are also not described. The record does not report how many participants contributed week-11 fatigue scores, whether missingness differed between arms, why assessments were missing, or whether imputation or another approach was used. It therefore does not establish whether the primary analysis included all randomized participants, only participants with observed measurements, or another analysis population. The analysis populations and handling of withdrawals are not reported in the registry record.

The record does not identify a prespecified estimand or specify how participants who stopped using the app, did not follow the assigned intervention, or had incomplete measurements were to be handled. These details affect what treatment effect an analysis represents. The planned baseline adjustment is described, but the full model and its implementation are not reported. No conclusion about missing-data bias, robustness, or multiplicity-adjusted inference can be drawn from the posted information.

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

The registry record shows that this was a randomized, parallel-group comparison of an app-delivered light intervention with a placebo light intervention, with fatigue assessed at week 11. It also describes the intended use of baseline fatigue in the primary analysis. These details clarify the question the study was designed to address; they do not provide the result of that comparison.

Without reported arm-level scores, an effect estimate, or an uncertainty interval, the magnitude and direction of any fatigue difference are unknown from this record. It is not possible to determine whether the data were compatible with a range of effects, whether an estimate was precise, or whether any observed difference would be meaningful to participants. The absence of reported statistical results should not be interpreted as evidence of no difference.

The same limitation applies to the listed secondary outcomes. Their inclusion identifies additional domains the trial intended to assess, but the registry record does not report findings for sleep disturbance, anxiety, depression, physical function, or overall health. The adverse-event counts also do not establish a causal relationship to the intervention or support a comparative safety conclusion.

In general, a trial result applies most directly to the participants, interventions, assessment methods, and follow-up actually studied. The record identifies three cancer-related populations and the app and glasses used in the two arms, but provides limited detail on participant characteristics and implementation. Without outcome results and fuller reporting, the record supports description of the trial question and design only. It does not support a conclusion that the intervention did or did not change fatigue, or that the findings apply beyond the studied setting.

12. Why This Trial Matters Statistically

This trial raises statistical questions that are important when evaluating symptom-focused interventions. Fatigue was assessed with a patient-reported scale at the final week, while baseline fatigue was measured using a different, one-item question. The registry description appropriately makes clear that the primary outcome was not a same-instrument change score. Keeping that distinction visible helps readers understand what the planned comparison can and cannot represent.

The stated use of baseline adjustment also matters. In general, a baseline measure can help account for initial symptom levels when estimating a follow-up difference. Interpretation still depends on the model specification, the quality of the baseline measure, the completeness of follow-up, and the uncertainty around the estimate. Those details and the estimate itself are not reported in the registry record.

The study also listed several secondary health outcomes. Multiple outcomes can describe a broader set of participant experiences, but the analysis plan needs to clarify how those outcomes relate to the primary question and how multiple comparisons will be interpreted. No such strategy or outcome results are reported in the registry record.

Finally, a completed randomized trial and a posted outcome result are not the same thing. The record documents enrollment, trial status, the planned comparison, and some adverse-event counts, but it does not report statistical results for the primary or secondary outcomes. This distinction is useful for readers: design information can identify what was intended, while estimation and uncertainty are necessary to evaluate what the observed data support.

13. 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 main limitation for statistical interpretation is that the registry record does not report results for the primary fatigue outcome. There are no final-week arm summaries, treatment-effect estimate, confidence interval, or p-value. The record lists no analyses, so it is not possible to evaluate the planned comparison or any departure from it.

The registry description states that the four-item PROMIS Fatigue measure was not available at week zero and that baseline adjustment used a separate one-item fatigue question. Consequently, the primary assessment described is a final-week comparison adjusted using a different baseline measure, not change from baseline on PROMIS Fatigue 4a. The record does not report the score distribution, the relationship between the measures, or the model specification in enough detail to assess how that adjustment was implemented.

Other design and analysis details are not reported in the registry record, including which party was masked, allocation concealment, participant flow, arm-specific analyzed sample sizes, missing-data methods, the analysis population, and a multiplicity strategy. The wearable sensor is listed, but its function and use are not described. These omissions limit assessment of bias, precision, and reproducibility.

The adverse-event listing includes deaths in both arms and no listed serious or other adverse events. The record does not report causes, timing, attribution, or further context, so these counts cannot be interpreted as intervention-related events or used for a comparative safety assessment. The record’s limited outcome and methods information prevents a full appraisal of either efficacy or safety.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Lighting Intervention for Cancer-related Fatigue — NCT04827446.
• Registry record last updated 2025-07-09; status last verified 2025-06.
• Results first posted 2025-07-09.
• 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.

17. Record Summary

The registry record describes a completed, randomized, single-masked, parallel-group trial of the SYNC app for cancer-related fatigue. Enrollment was 139. The intervention arm used a light intervention through the full SYNC app with blue-light blocking glasses; the control arm used a placebo light intervention through the app with clear glasses. The listed populations include breast cancer, prostate cancer, and people who have undergone autologous HSCT.

The primary endpoint was PROMIS Fatigue 4a at week 11. The planned comparison was between arms, controlling for baseline fatigue with a separate one-item question. Secondary outcomes included sleep disturbance, anxiety, depression, physical function, and overall health. The registry record does not report outcome estimates or statistical test results, and no analyses are listed. It also does not report detailed missing-data, multiplicity, or analysis-population methods. The record therefore describes the trial design and intended assessment, but does not permit interpretation of the intervention’s observed effect on fatigue.