Culturally Adapted Mobile Treatment of Chronic Pain in Adolescent Survivors of Pediatric Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Culturally Adapted Mobile Treatment of Chronic Pain in Adolescent Survivors of Pediatric Cancer (NCT05746429), a non-randomized na study. The primary outcome is Pain Intensity.

2. Clinical Question

The study combined a cultural-adaptation phase with a feasibility trial. The clinical question for the feasibility phase concerned change in pain intensity among adolescent survivors of childhood cancer with chronic pain who were assigned to mobile CBT paired with active tDCS or sham tDCS. The registry record describes a non-randomized comparison, so the arms should not be treated as a like-for-like control comparison.

3. Trial Design

This was a prospective, parallel, non-randomized study listed as completed. Its registered enrollment was 68. The registry lists the phase as NA and identifies St. Jude Children's Research Hospital as the sponsor. The recorded study start was 2023-04-06 and primary completion was 2024-10-29.

The study had two linked components. First, virtual meetings and focus groups gathered feedback from survivors during cultural adaptation of a mobile CBT program for chronic pain and tDCS procedures. The brief summary anticipated approximately 60 participants for focus groups and approximately 30 for the feasibility study, for a total of about 90. These are anticipated counts in the summary, not a report of the number who actually took part in each component.

After the adaptation phase, the feasibility study assigned eligible participants to mobile CBT plus active tDCS or mobile CBT plus sham tDCS. Both stimulation regimens were described as targeting the dorsolateral prefrontal cortex for 20 minutes twice a week for 6 weeks. The registry lists no masking. Because allocation was non-randomized, differences between arms may reflect factors other than the stimulation condition; the record explicitly cautions that the arms are not a like-for-like control comparison.

The registry record does not report how assignment was determined, whether allocation procedures changed during recruitment, or the reasons for any differences between the planned counts and registered enrollment. It also does not report a protocol-level statistical plan or a sample-size justification. The study's completed status indicates its registry status, but does not itself establish that numerical results for the primary endpoint were reported.

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: In the cultural adaptation phase, participants took part in focus groups and did not receive any intervention. In the feasibility study, all participants received the adapted mobile CBT. Participants were also assigned to active or sham transcranial direct current stimulation (tDCS) using an ABAB design within racial/ethnic groups (Hispanic, non-Hispanic Black, non-Hispanic White).

Cultural Adaptation

Feasibility Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Include participants in the feasibility study who were assigned to an experimental arm and completed both the baseline and 6-week assessment. All participants were included in the 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 Pain Intensity, measured over Baseline (enrollment) and up to 8 weeks from start of feasibility study.

The primary endpoint was pain intensity, assessed with the Brief Pain Inventory-Short Form. Its pain-severity score averages four items: worst pain and least pain in the last 24 hours, average pain, and current pain. Each item uses a 10-point rating scale from 0, no pain, to 10, pain as bad as you can imagine. The resulting score ranges from 0 to 10, with higher scores indicating greater pain intensity.

The endpoint concerns change from baseline rather than a score at a single visit. Repeated measurement allows investigators to describe whether participants' reported pain intensity shifted during the intervention period. For a treatment comparison, the central statistical question is not merely whether each arm changed from baseline, but how the changes compare between arms and how precisely that contrast is estimated. That is a general statistical distinction, not a claim about an analysis performed in this study.

The registry describes the timeframe as baseline and up to 8 weeks from the start of the feasibility study. Its analysis-population description specifies completion of baseline and the 6-week assessment. This difference in wording is not explained in the registry record. Numerical baseline scores, changes, and uncertainty estimates are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a continuous primary outcome summarized as a mean with standard deviation. It describes the score and intended comparison, but does not report the statistical model, test, confidence interval, p-value, or numerical arm-level results. The following concepts explain how such information is generally interpreted; they do not describe analyses confirmed in the registry record.

What does a mean change represent?

For a continuous outcome, a mean is the arithmetic average across the observations included in an analysis. A mean change represents the average difference between a participant's follow-up score and baseline score, aggregated across the analysis group. The direction depends on how change is defined. Because higher scores on this pain scale indicate greater intensity, a downward score change would indicate lower reported intensity on the scale, while an upward change would indicate higher reported intensity. The registry does not state the sign convention used to calculate change, or report the resulting values.

A mean can be useful because it compresses a set of scores into a single measure of central tendency. It can also obscure variation: the same average change can arise when participants have similar changes or when individual changes differ substantially. The standard deviation is a descriptive measure of that spread. It is not the standard error and does not, by itself, quantify the precision of the mean or of a comparison between arms.

Why is the between-arm contrast important?

In a two-arm study, change within each arm and difference between arms answer different questions. A group may change from baseline for reasons that affect both groups, including changes over time or the experience of participating in a study. A between-arm contrast asks whether the average change differs between the active and sham groups. General statistical practice evaluates that contrast with an estimate and a measure of uncertainty, rather than relying only on separate within-group changes. No numerical between-arm contrast is reported in the registry record.

Baseline and follow-up values from the same participant are related observations. Analyses of repeated measurements should account for that relationship if they use both measurements directly. Other approaches can analyze change scores or adjust follow-up scores for baseline. These methods can target related but not identical estimands and rely on different assumptions. The analysis method used for this outcome is not reported in the registry record, so no particular model or adjustment should be inferred.

What does a confidence interval add?

As a general statistical explanation, a confidence interval expresses the uncertainty around an estimated effect under the assumptions of the analysis. A narrower interval indicates greater statistical precision; a wider interval indicates less precision. The interval helps readers assess which effect sizes remain compatible with the data, rather than focusing only on a single point estimate. It does not account automatically for design limitations such as non-random allocation, measurement limitations, or missing data. No confidence interval for the primary outcome is reported in the registry record.

A p-value, when reported, describes how unusual the observed data or more extreme data would be under a specified null hypothesis and statistical model. It does not measure the probability that the null hypothesis is true, and it does not quantify clinical importance. A p-value also does not repair confounding or other design limitations. The registry record does not report a p-value for the primary outcome or identify a test used to obtain one.

Why can non-random allocation affect interpretation?

In general, randomization helps make treatment groups comparable in expectation by assigning participants through a chance process. In a non-randomized study, group membership may be associated with participant or study characteristics. If such characteristics also relate to pain change, an unadjusted difference may combine the effect of the assigned condition with those other differences. Statistical adjustment can sometimes address measured characteristics, but it cannot ensure control of unmeasured factors. The assignment procedure and any adjustment strategy are not reported in the registry record. The registry specifically cautions that the arms are not a like-for-like control comparison.

How should over-dispersion be understood?

Over-dispersion is a general concern when observed variability is greater than a statistical model assumes. For a continuous outcome, large variation in individual change can make an estimated mean or between-arm difference less precise than expected under a model with smaller variability. A model that understates variability may also produce uncertainty estimates that are too narrow. The registry identifies standard deviation as the dispersion measure for the primary outcome, but it does not report the observed standard deviations or a model-based assessment of dispersion. There is therefore no basis in the registry record for claiming that over-dispersion occurred or that a particular correction was needed.

What can planning calculations say?

Sample-size calculations are prospective planning tools: they estimate how many participants per arm might be needed under stated assumptions to detect a specified effect with a chosen significance level and power. The registry describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. The values are planning illustrations, not observed power, and they are not the trial's original design justification. The registry record does not report the original sample-size justification, and the numerical outcome estimates needed to interpret a planning illustration are not reported in the registry record.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Experimental: Arm I (Mobile CBT + Active tDCS)", "Sham Comparator: Arm II (Mobile CBT + Sham tDCS)")
n   <- c(14, 16)
m   <- c(-0.96, -0.56)
sp  <- c(1.7, 2.5)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Experimental: Arm I (Mobile CBT + Active tDCS)  14  -0.960  1.700  -1.942  0.022
CARM  Sham Comparator: Arm II (Mobile CBT + Sham tDCS)  16  -0.560  2.500  -1.892  0.772

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 15 outcome measures, but does not report analysis entries. It identifies pain intensity as the primary outcome. The hierarchy or status of the remaining outcomes, the number of hypotheses tested, and any adjustment for multiple comparisons are not reported in the registry record. In general, testing many outcomes can increase the chance that at least one result appears noteworthy by chance. Prespecifying a primary outcome and an analysis plan can help readers distinguish confirmatory questions from exploratory ones; the record does not provide enough detail to assess that distinction beyond naming the primary endpoint.

The stated analysis population includes participants assigned to an experimental arm who completed both baseline and the 6-week assessment, and the description says all participants were included in the analysis. The record does not explain how those statements apply to participants without both assessments. It does not report the amount or pattern of missing primary-outcome data, reasons for missingness, imputation procedures, or sensitivity analyses. Missing-data methods matter because results can depend on why measurements are absent and how the analysis handles them.

Other analysis details are also not reported in the registry record: the statistical model, covariate adjustments, handling of protocol deviations, and whether any interim analyses were conducted. No statistical plan or sample-size justification is reported. These omissions limit the ability to assess whether the analysis followed prespecified procedures and whether the reported population matches the intended one. They should not be filled in by assuming a conventional method.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists zero serious adverse events in each of the three groups: the interview group, Arm I with mobile CBT and active tDCS, and Arm II with mobile CBT and sham tDCS. It lists zero deaths in all three groups. For other adverse events, it records 0 affected among 38 at risk in the interview group, 14 among 14 at risk in the active arm, and 15 among 16 at risk in the sham arm. These are the registry's reported counts; they should be read within their separate groups, not combined.

The serious-event counts describe what was recorded in the registry and do not show that serious events are impossible or that a treatment is safe in other settings. The record's list of top serious-event terms is empty. It does not report event descriptions, severity grading for the other events, timing, duration, attribution to study procedures, or the criteria used to collect and classify them. The interview group represents the adaptation component, whereas the other groups represent the feasibility arms, so their event counts concern different study activities.

Counts of participants affected are not the same as counts of all event episodes: the registry does not state whether a participant could have had more than one event. No causal interpretation of the other-event counts is supported by the information reported.

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

The record describes a study intended to culturally adapt mobile CBT and tDCS procedures, followed by a feasibility comparison of mobile CBT paired with active or sham tDCS. Its primary outcome was change in a pain-intensity score, measured with a four-item scale. The registry also reports study status, enrollment, design features, and adverse-event counts.

What the record does not report is the numerical primary-outcome change in either arm or a numerical comparison between arms. It therefore does not allow readers to judge the size, direction, or precision of the pain-change contrast from the registry information presented. A completed status is not equivalent to a reported endpoint result, and adverse-event counts do not answer whether pain scores changed differently between the study arms.

The non-randomized design is central to interpretation. Even if a difference in pain change were reported, the registry warns that the arms are not a like-for-like control comparison. Assignment-related differences or other factors could contribute to an observed contrast. The assignment process and any statistical adjustment are not reported in the registry record, so the degree to which such influences were addressed cannot be assessed.

The intended contribution of a feasibility study is generally to examine whether study procedures and measures can be implemented and to inform later research; this is a general description, not a registry-reported conclusion about this particular study. The record does not report feasibility criteria or results, nor does it provide a basis for judging whether the adaptation process met a prespecified standard. It also does not establish a treatment benefit or lack of benefit. Those conclusions would require reported results interpreted alongside the study design, uncertainty, missing data, and analysis methods.

Thus, the registry information supports a description of the study question and design, but not a conclusion about efficacy. The available safety counts likewise require context about event definitions and attribution before they can be interpreted beyond the recorded counts.

14. Why This Trial Matters Statistically

This study raises statistical questions that are important when research combines cultural adaptation with a clinical feasibility comparison. The adaptation phase used survivor feedback to develop the mobile CBT program and tDCS procedures. The feasibility phase then evaluated the adapted intervention in survivor groups that included non-Hispanic Black, Hispanic, and non-Hispanic White participants. Keeping these components distinct helps readers understand that focus-group feedback and pain-score change are different kinds of evidence.

The primary endpoint is a continuous score measured at baseline and follow-up. Interpreting it requires more than reading a single average: the direction and magnitude of change, the variability of individual responses, the contrast between arms, and the precision of that contrast all matter. Yet the registry does not report the numerical pain-change results or inferential analyses. This makes it especially important not to infer an outcome from study completion, enrollment, or the intervention description.

The non-randomized allocation is also statistically consequential. Without random assignment, the active and sham arms cannot be assumed to be comparable at baseline or in other characteristics. The registry explicitly cautions against treating them as a like-for-like control comparison. A clear account of allocation, baseline comparability, and any adjustment would be important for interpreting a future estimate, but those details are not reported in the registry record.

Finally, the record illustrates why feasibility, efficacy, and safety are separate questions. An intervention can be studied for feasibility without establishing an effect on the primary endpoint; event counts do not measure pain-score change; and an empty list of serious-event terms does not settle all safety questions. Distinguishing these aims prevents the design and registry status from being mistaken for evidence of a clinical effect.

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 primary limitation for interpreting the main outcome is that the registry record does not report numerical pain-intensity changes, a between-arm contrast, confidence intervals, or p-values. Without those results, neither the magnitude nor precision of the outcome comparison can be evaluated. The record identifies the outcome as a mean with standard deviation, but does not report those values.

Allocation was non-randomized, and the registry cautions that the arms are not a like-for-like control comparison. The procedure used to assign participants and any adjustment for baseline or other characteristics are not reported in the registry record. This constrains causal interpretation even if an arm difference were available.

The endpoint timeframe is described as baseline and up to 8 weeks from the start of the feasibility study, while the analysis-population description refers to completing the baseline and 6-week assessment. The record does not explain the wording difference. It also does not report missing-data counts, reasons for missing assessments, or methods for handling incomplete records.

The record describes a cultural-adaptation component and a feasibility trial, but it does not report actual participation counts for each component, feasibility criteria, or their results. The registered enrollment is 68, while the brief summary describes anticipated counts of approximately 60 for focus groups and approximately 30 for the feasibility study. Those anticipated figures are not actual component-specific enrollment results.

Finally, the registry does not report a statistical analysis plan, multiplicity procedures, interim-analysis details, or a sample-size justification for the original study design. These limitations restrict assessment of prespecification and of how broadly the findings could apply. They do not establish that any particular analysis or procedure was omitted from the conduct of the study; those details are simply not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Culturally Adapted Mobile Treatment of Chronic Pain in Adolescent Survivors of Pediatric Cancer — NCT05746429.
• Registry record last updated 2026-02-04; status last verified 2026-02.
• Results first posted 2026-02-04.
• 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

NCT05746429 is a completed, prospective, non-randomized parallel study sponsored by St. Jude Children's Research Hospital. It examined cultural adaptation of mobile CBT and tDCS procedures, followed by a feasibility study comparing mobile CBT with active tDCS against mobile CBT with sham tDCS in childhood cancer survivors with chronic pain. The registry lists enrollment of 68, no masking, and phase NA.

The primary outcome was change in Brief Pain Inventory-Short Form pain intensity, with higher scores indicating greater pain intensity. The record reports zero serious adverse events and zero deaths in each listed group, alongside the other-event counts described in the safety information. Numerical primary-outcome changes, comparative effect estimates, and inferential analyses are not reported in the registry record. Because allocation was non-randomized, the registry cautions that the arms are not a like-for-like control comparison.