The PRISM Intervention: a Multi-site Randomized Controlled Trial for Adolescents and Young Adults With Advanced Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The PRISM Intervention: a Multi-site Randomized Controlled Trial for Adolescents and Young Adults With Advanced Cancer (NCT03668223), a randomized na study. The primary outcome is Pediatric Quality of Life Cancer Module.

2. Clinical Question

3. Trial Design

The registry record describes a completed, multi-site randomized controlled trial with randomized allocation, a parallel-group model, and single masking. It lists 269 participants enrolled. The intervention was PRISM, a behavioral resilience skills training program; the comparator was usual care, described as standard psychosocial care. The record does not say who was masked, how allocation was generated or concealed, or how the intervention was delivered across sites.

The primary outcome was the Pediatric Quality of Life Cancer Module score at three months. Three secondary outcomes are listed at the same timeframe: the Hospital Anxiety and Depression Scale (HADS) Total Score, the Snyder Hope Scale, and the Connor Davidson Resilience Scale. The registry lists four outcome measures in total and posts group summaries for all four. The primary outcome summaries contain 69 participants in the PRISM group and 76 in usual care; the registry does not explain how those summary populations relate to the overall enrollment.

The recorded start date is 2019-04-15, and the primary completion date is 2024-01-23. The status is completed, and the phase is listed as NA. The registry record does not report the original sample-size justification, the original design assumptions, an analysis plan, or reported analyses. It also does not describe the timing or conduct of any interim analyses. Those details should not be inferred from the posted outcome summaries or the separate planning illustrations.

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: Of the 269 consented, 30 of those participated in the Run-in portion of the study not included in this randomization. Of the 239 consented to the RCT, 195 completed the required baseline survey and were randomized to the intervention or control arm. Forty-four participants did not complete the baseline survey and were not randomized; these participants are included in pre-assignment only.

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 Pediatric Quality of Life Cancer Module, measured over 3-months.

The primary endpoint is the Pediatric Quality of Life Cancer Module score at three months. The registry describes this 27-item scale as designed to assess pediatric cancer-specific health-related quality of life. Each item is rated on a five-point Likert scale, with responses ranging from 0, “never,” to 4, “almost always.” The total scale range is 0–100, and higher scores represent better health-related quality of life.

A quality-of-life measure is relevant to a trial of a psychosocial skills intervention because it captures a patient-reported aspect of health-related experience, rather than a clinical event or laboratory measurement. That is a general explanation of why such an endpoint can be used; the registry record does not state its specific rationale for selecting this measure as primary. The endpoint is expressed as a continuous score, and the posted results summarize each group with a mean and standard deviation. The comparison therefore describes the average scores in the two groups at the stated follow-up, not the experience of every participant. The registry does not report additional details about scoring, missing items, or how scores were handled when a full questionnaire was unavailable.

7. Results Posted in the Registry

• Promoting Resilience in Stress Management (PRISM): mean 66.89 versus 68.41 on control; difference -1.52 (95% CI -7.41 to 4.37), standardized effect d = -0.08; z-test p = 0.613.

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.

Hospital Anxiety and Depression Scale (HADS) Total Score

• 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:
  • Promoting Resilience in Stress Management (PRISM): mean 8.27 versus 9.94 on control; difference -1.67 (95% CI -4.04 to 0.70), standardized effect d = -0.23; z-test p = 0.167.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Promoting Resilience in Stress Management (PRISM) and the control. The interval gives the range of effects that remain compatible with the data.

Snyder Hope Scale

• 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:
  • Promoting Resilience in Stress Management (PRISM): mean 48.06 versus 46.89 on control; difference 1.17 (95% CI -3.16 to 5.50), standardized effect d = 0.09; z-test p = 0.597.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Promoting Resilience in Stress Management (PRISM) and the control. The interval gives the range of effects that remain compatible with the data.

Connor Davidson Resilience Scale

• 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:
  • Promoting Resilience in Stress Management (PRISM): mean 28.05 versus 27.45 on control; difference 0.60 (95% CI -2.35 to 3.55), standardized effect d = 0.07; z-test p = 0.691.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Promoting Resilience in Stress Management (PRISM) and the control. The interval gives the range of effects that remain compatible with the data.

The three secondary outcomes cover anxiety and depression, hope, and resilience at three months. Their posted mean differences point in different directions: the PRISM group has a lower mean HADS Total Score and higher mean scores on the hope and resilience measures than usual care. The intervals reported for these comparisons include zero. This pattern is broadly consistent with uncertainty rather than a uniform separation across all posted measures; it does not provide a clear, consistent secondary-outcome signal that changes the reading of the primary result.

These outcomes are related to the intervention’s resilience-skills focus, but each measures a different construct from cancer-specific quality of life. Agreement or disagreement across them does not by itself validate a result, and a difference on one scale would not automatically imply a difference on another. The primary endpoint remains the trial’s designated main outcome in the registry record. Secondary results can add context, but they do not replace the primary comparison.

The posted secondary comparisons are unadjusted. When several outcomes are examined, the chance of at least one apparently unusual finding can increase; as a general statistical principle, multiplicity procedures can address that issue, depending on the prespecified analysis strategy. The registry record does not report a multiplicity plan or adjusted secondary analyses. Accordingly, the secondary p-values should carry less weight than they would under a clearly specified, prespecified multiplicity framework. Their interpretation is also limited by the absence of reported analysis methods, analysis populations, and missing-data handling. The overall pattern is best treated as descriptive evidence across several related measures rather than as a set of definitive separate conclusions.

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

• Hospital Anxiety and Depression Scale (HADS) Total Score
• Snyder Hope Scale
• Connor Davidson Resilience Scale

9. Statistical Interpretation

10. Statistical Methods Explained

The posted primary outcome is continuous, and the registry reports a mean and standard deviation for each group. The comparison is a mean difference, with the PRISM group first and usual care as the reference: a negative value means the PRISM group’s posted mean is lower, while a positive value means it is higher. The estimate is -1.52. This direction is a description of the group summaries, not evidence by itself about why the scores differ.

What does a mean and standard deviation describe?

As a general statistical explanation, a mean is the arithmetic average of the observed scores in a group. A standard deviation describes how spread out individual scores are around that group mean. The primary outcome standard deviation is 18.07 in each group. A standard deviation is not the same as a confidence interval: it describes variation among scores, while a confidence interval describes uncertainty around an estimated quantity. The registry lists the outcome as a mean with standard deviation, but does not describe the distribution of scores or any checks of analysis assumptions.

How should the mean difference be read?

The mean difference compares group averages at the reported three-month timeframe. It does not describe every participant’s change from baseline; baseline results and within-person changes are not reported in the registry record. Nor does a difference in group means show that each participant in one group had a score higher or lower than each participant in the other group. The comparison is based on the group-level summaries.

What does the confidence interval add?

In general, a confidence interval presents a range of estimates compatible with the observed data and the method used to calculate it. The primary outcome interval extends from -7.409 to 4.369. Because it includes zero, the posted result is compatible with a lower PRISM mean, no mean difference, or a higher PRISM mean under the interval’s assumptions. The interval does not establish that each value inside it is equally plausible, and it does not account for unreported sources of bias or analysis choices. The registry record does not state the confidence level or the method used to form the interval.

What is the role of the p-value?

The posted unadjusted p-value for the primary comparison is 0.613. As a general explanation, a p-value measures how unusual data at least as discrepant as those observed would be under a specified null model and its assumptions. It is not a measure of the size or importance of an effect, and it is not the probability that the null model is correct. “Unadjusted” indicates that the result is presented without a reported multiplicity adjustment. The registry record lists no reported analyses, so it does not specify the analysis procedure associated with this p-value or whether other planned analyses were conducted.

What do the planning illustrations represent?

The planning figures are illustrations based on the observed effect, not the trial’s original sample-size design. Their stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; each scenario uses the stated fraction of the observed effect to detect. In general, power is the chance that a specified analysis will detect a specified effect under its assumptions. The 80% and 90% columns describe the number of participants per arm used in those planning scenarios to target the corresponding power level. The trial’s own design assumptions and sample-size justification are not reported in the registry record, and the planning values do not establish the trial’s achieved power.

All reported outcome comparisons are based on continuous scores summarized with means and standard deviations. The record does not identify the exact statistical tests, covariate adjustments, missing-data methods, analysis populations, or model diagnostics. Randomized allocation and a parallel-group design describe the trial structure, but they do not reveal which statistical model was used for the posted comparisons. Those unreported methods should not be inferred from the format of the result summaries.

11. Confidence Intervals and Precision

The primary mean difference is -1.52, with a confidence interval from -7.409 to 4.369. The interval includes zero and extends in both directions. This means that the posted estimate is not sufficiently precise to determine from the interval alone whether the PRISM-group mean was lower or higher in the population represented by the analysis. It also indicates uncertainty about the magnitude of any difference compatible with the reported result.

Precision concerns the width of an interval and the range of values it leaves plausible under its assumptions. It is distinct from whether an estimate is important to patients or whether a result is statistically persuasive. The registry record does not report a threshold for a meaningful difference on this scale, so the interval cannot be judged against a stated clinical-importance criterion. The record also does not identify the confidence level or interval calculation method, limiting how fully the interval’s construction can be assessed.

The posted primary result uses 69 participants in the PRISM group and 76 in usual care, while overall enrollment is recorded as 269. The registry does not explain the relationship between these numbers or report missing-data handling. Therefore, the interval’s precision should be understood as precision for the reported comparison, not as assurance that all enrolled or randomized participants are represented. A narrower interval would generally provide more precision under a given method, but interpretation also depends on study design, analysis choices, and the completeness of outcome data.

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 events. They illustrate sample sizes under the listed assumptions: a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is set at the stated fraction of the observed effect. These are planning illustrations and are not observed power.

The 80% power column gives the number of participants per arm in the illustration for a design intended to have an 80% chance of detecting the specified effect under those assumptions. The 90% power column gives the corresponding number per arm for a 90% target. These figures are not a statement about how likely the trial’s result was to be correct, and they do not describe the probability that the trial actually found an effect.

The planning rows consider the full observed effect and smaller fractions of that effect. As a general statistical principle, smaller effects are harder to distinguish from random variation, so more participants are needed to achieve the same target power under otherwise unchanged assumptions. The figures are tied to the observed effect in this study and to the stated simplified assumptions; they do not constitute the original sample-size justification. The registry record does not report the trial’s own design effect, target power, or original sample-size assumptions. The displayed planning values should therefore be read as hypothetical planning aids, not as evidence about the trial’s adequacy or the result’s certainty.

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 = -1.520; pooled standard deviation σ = 18.070.
2. n = 2 × (1.96 + 0.842)² × 18.070² / -1.520² = 2,218.5, rounded up to 2,219 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 <- -1.52                      # observed difference in means
sigma <- 18.07                     # 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(3668223)
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 = 2,219 (80% power), 2,970 (90% power)
 75% of observed effect: n per arm = 3,945 (80% power), 5,280 (90% power)
 50% of observed effect: n per arm = 8,875 (80% power), 11,880 (90% power)
power.t.test: 2219.5 
Simulated power at n = 2,219 per arm: 0.805 (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. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome and three secondary outcomes, each with posted group summaries and comparisons. The record does not report a multiplicity strategy, such as a hierarchy among outcomes or an adjustment to account for testing several outcomes. The posted comparisons are unadjusted. In general, examining multiple outcomes can increase the chance that at least one result appears notable by chance, so the results should be interpreted with attention to which outcome was primary and whether secondary analyses were prespecified. The registry record does not provide enough information to determine how those decisions were made.

The registry reports no analyses under its reported-analyses listing. It also does not provide a statistical analysis plan, identify the precise methods used for the posted comparisons, or say whether covariates were included. The original sample-size justification and trial design assumptions are not reported. These omissions make it difficult to compare the posted summaries with a prespecified analysis strategy or to assess whether the reported comparisons were planned before outcome data were examined.

The record does not explain how missing outcome data were handled, how many participants were eligible for each outcome, or which analysis population was used. It does not specify whether results follow an intention-to-treat, per-protocol, or other population definition. The primary outcome summaries include 69 participants in PRISM and 76 in usual care, compared with overall enrollment of 269, but the reason for that difference is not reported in the registry record. No conclusion about dropout, exclusions, or missingness mechanisms should be drawn from those counts alone. These gaps affect interpretation of both the estimated differences and their precision.

15. 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 lists 0 participants with serious adverse events among 99 at risk in the PRISM group and 0 among 96 at risk in usual care. The run-in group lists 0 among 30 at risk. For other adverse events, the registry also lists 0 participants affected in each of those groups. Deaths are recorded as 10 in PRISM, 5 in usual care, and 0 in run-in. These are the registry’s group-level counts; the record does not provide causes of death or further details about timing.

These figures should be read as counts recorded for the stated groups, not as proof that an intervention caused or prevented an event. The registry does not provide event descriptions, attribution, severity details beyond the serious-event category, or comparative safety analyses. It also does not explain the run-in group’s relationship to the randomized comparison. The figures therefore do not support a complete assessment of safety or an interpretation of the differences in deaths between groups.

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

The posted primary outcome comparison describes the mean cancer-specific quality-of-life scores in the PRISM and usual-care groups at three months. The PRISM mean was 66.89, compared with 68.41 for usual care, and the mean difference was -1.52. The confidence interval extends from -7.409 to 4.369 and includes zero. Taken together, these statistics show a small difference between the posted means in the direction of a lower PRISM-group score, with substantial uncertainty about the direction and size of the underlying difference.

This result does not demonstrate that the groups are equivalent. Establishing equivalence would require an appropriate design and a prespecified equivalence margin, neither of which is reported in the registry record. Nor does the result establish that PRISM caused a lower score, that it caused a higher score, or that it had no effect. The posted summaries do not establish a cause-and-effect explanation on their own.

The result also does not describe longer-term outcomes, individual participant experiences, or outcomes beyond the measures posted at three months. It cannot establish how participants’ scores changed from baseline because baseline scores and change analyses are not reported in the registry record. The three secondary outcome summaries provide information about other measured constructs, but their unadjusted status and the lack of a reported multiplicity strategy limit the strength of conclusions drawn from them.

Finally, the outcome counts and analysis methods are incompletely described. The registry records enrollment of 269, while the primary summaries include 69 and 76 participants in the two comparison groups. The record does not explain this relationship, specify the analysis population, or describe missing-data handling. These limitations mean that the findings should be interpreted as the posted three-month summaries, not as a complete account of all enrolled participants or all possible trial outcomes.

17. Why This Trial Matters Statistically

Statistically, this trial illustrates the distinction between an estimated group difference and the uncertainty around that estimate. The primary mean difference is -1.52, but its interval spans values below and above zero. Focusing only on the direction of the point estimate would omit important information about its precision. The interval and the group summaries together provide a more complete description of what the posted data indicate.

The trial also reports several related outcomes. Their different directions show why an overall interpretation should distinguish the primary endpoint from secondary measures and should account for multiplicity. Without a reported adjustment or analysis hierarchy, secondary comparisons are useful as descriptive context but should not be treated as independent confirmatory findings. This is a general statistical concern when several outcomes are assessed.

Another important statistical issue is the gap between total enrollment and the numbers included in the posted primary summaries. The registry record does not explain that difference or report the analysis population and missing-data methods. Those details matter because the population summarized and the way unavailable outcomes are handled can affect both estimates and their precision.

Finally, the separate planning illustrations show how sample-size requirements depend on the effect size a study is intended to detect, under stated assumptions. They are not the original design rationale for this trial. Because the registry record does not report that rationale or a statistical analysis plan, the illustrations cannot answer whether the trial was designed around a particular target effect. Together, these points make transparent reporting of analysis populations, missingness, multiplicity, and design assumptions important to interpreting randomized trial results.

18. 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.

Several trial-specific details needed for a fuller interpretation are not reported in the registry record. Although the design is described as single-masked, the masked parties are not identified. The record does not explain allocation generation or concealment, nor does it describe the intervention’s delivery or variation across sites. These omissions prevent a detailed assessment of implementation and potential sources of bias from the registry entry alone.

The record lists enrollment of 269, whereas the posted primary endpoint summaries include 69 participants in PRISM and 76 in usual care. The reason for this difference is not reported. There is no stated analysis population, participant flow explanation, missing-data method, or account of how many participants contributed to each secondary endpoint. Baseline outcome scores and change-from-baseline analyses are also not reported, limiting interpretation to the posted three-month group summaries.

The registry does not report the original sample-size justification, a statistical analysis plan, the specific analysis method, or whether covariates were adjusted for. It lists no reported analyses and provides no multiplicity plan for the primary and secondary outcomes. The confidence-interval construction and confidence level are not described. As a result, the summaries can be described, but the full analytic context and prespecification cannot be independently assessed from the registry record.

For safety, the group counts are not accompanied by event descriptions, attribution, or causes of death. The run-in group is listed separately, but its role in relation to the randomized comparison is not explained. These reporting limitations do not establish that problems occurred; they mark what cannot be resolved from the registry record.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: The PRISM Intervention: a Multi-site Randomized Controlled Trial for Adolescents and Young Adults With Advanced Cancer — NCT03668223.
• Registry record last updated 2026-10-14; status last verified 2026-09.
• Results first posted 2024-10-24.
• 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.

22. Record Summary

The registry record describes NCT03668223 as a completed, multi-site randomized controlled trial of PRISM among adolescents and young adults with advanced cancer. It lists 269 participants enrolled, randomized allocation, a parallel-group model, and single masking. PRISM is described as behavioral resilience skills training; the comparator is usual care, described as standard psychosocial care.

The primary endpoint is the Pediatric Quality of Life Cancer Module mean score at three months. The posted mean difference is -1.52, with a confidence interval from -7.409 to 4.369 and an unadjusted p-value of 0.613. Three secondary outcomes are also posted. The record does not report the original sample-size justification, analysis plan, analysis populations, missing-data methods, or multiplicity strategy. Planning figures are separate illustrations based on the observed effect and stated assumptions, not the original trial design.