The Effects of Exercise on Distress, Quality of Life, and Biomarkers in Ovarian Cancer Survivors: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Effects of Exercise on Distress, Quality of Life, and Biomarkers in Ovarian Cancer Survivors (NCT03641287), a randomized na study. The primary outcome is Change in Quality of Life Measured Using the RAND 36-item Short Form Health Survey Physical Component Score.

2. Clinical Question

3. Trial Design

The registry identifies this as a randomized, single-masked, parallel-group trial. Its phase is listed as NA. The enrollment is 64. The record status is terminated; it lists a start date of 2018-12-05 and a primary completion date of 2022-09-30. The reason for termination is not reported in the registry record.

In the intervention arm, participants met with an exercise physiologist for 1, 60 minute session and received an individualized home exercise prescription aiming for moderate aerobic exercise over 150 minutes per week for up to 24 weeks. The description also mentions telephone-based motivational support, but the text recorded for that element is incomplete. The comparator arm maintained habitual activity and received general education material about ovarian cancer and survivorship for 24 weeks; exercise intervention was offered after 24 weeks.

The primary outcome was mean change from baseline to 24 weeks in the RAND 36-item Short Form Health Survey Physical Component Score. The posted arm summaries include 28 participants in the exercise group and 27 in the habitual-activity group. These are the counts attached to the posted outcome summaries; the record does not explain the difference between those counts and the enrollment figure. Safety summaries use separate at-risk counts, which should not be treated as interchangeable with the outcome counts.

Although the trial title and brief description mention distress, quality of life, and biomarkers of angiogenesis and chronic stress, the record analyzed contains no posted secondary outcome results. It lists seven outcome measures but reports no secondary outcome results for this analysis. The detailed original sample-size justification, the reason for termination, and the identities of people masked are not reported in the registry record.

4. Participant Flow and Accounting

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

Overall Study

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 Quality of Life Measured Using the RAND 36-item Short Form Health Survey Physical Component Score, measured over Baseline up to 24 weeks.

The primary endpoint is change in the RAND 36-item Short Form Health Survey Physical Component Score from baseline to 24 weeks. The score is intended to capture physical aspects of health-related quality of life. The measure assesses eight subscales: physical functioning, bodily pain, role limitations due to physical health problems, role limitations due to personal or emotional problems, emotional well-being, social functioning, energy/fatigue, general health perceptions, and perceived change in health.

Each subscale can range from 0 to 100. The Physical Component Score combines the subscales using a standardized algorithm; its possible range is 20 to 60. The registry states that the general US population has a mean of 50 and standard deviation of 10 for this score, and that higher scores indicate better quality of life. These properties describe the measure, not the average score or change observed in this trial.

Using change from baseline focuses the comparison on how the score shifts during the study period, rather than only on the score at a single time. Comparing mean changes between randomized groups addresses whether their average observed changes differed. The posted result is a group contrast; it does not describe every participant’s experience, and it does not establish how the score relates to other outcomes such as distress or biomarkers. Those other outcomes are not reported in the registry record in the results analyzed.

7. Results Posted in the Registry

• Arm II (Habitual Level of Physical Activity): mean 4.61 versus 4.37 on control; difference 0.24 (95% CI -4.17 to 4.65), standardized effect d = 0.03; z-test p = 0.915.

8. Statistical Interpretation

9. Statistical Methods Explained

The result is a comparison of means for a continuous outcome. The registry defines the primary measure as mean change in the RAND 36-item Short Form Physical Component Score from baseline to 24 weeks. Each arm’s posted summary is a mean with a standard error. The between-group estimate is reported as a mean difference, with the habitual-activity arm compared against the aerobic-exercise arm.

What does a mean difference describe?

General statistical explanation: A mean difference subtracts one group’s average from the other group’s average, using a stated direction. That direction matters: a positive value in this result means the habitual-activity group’s average change is higher than the exercise group’s average change. The estimate is about group averages. It does not say that every participant changed by that amount, and it does not show the distribution of individual changes.

The posted arm means are 4.37 for aerobic exercise and 4.61 for habitual physical activity. The registry reports the contrast as 0.24. Those values describe the average changes under the posted analysis. The record does not describe adjustment for baseline score or other covariates in the result analyzed. Whether any additional adjustment was part of the original analysis is not reported in the registry record.

What does the standard error tell the reader?

General statistical explanation: A standard error quantifies the uncertainty in an estimated statistic, such as a group mean. It is different from a standard deviation, which describes variability among observations. Smaller standard errors generally correspond to more precise estimates, while larger standard errors indicate more uncertainty. In the posted summaries, the standard errors are 0.99 for the exercise arm and 2.02 for the habitual-activity arm. The record does not provide individual participant scores, so these standard errors should not be used to infer the full spread or shape of participant-level changes.

The comparison’s confidence interval is constructed to show a range of values compatible with the data under the analysis assumptions. It incorporates uncertainty in the estimated contrast. The interval reported for this result is -4.169 to 4.649. Because zero lies within that range, the data do not distinguish the estimate from zero at the conventional level associated with that interval. The interval’s breadth is also important: it leaves considerable uncertainty about the magnitude and direction of the underlying mean contrast.

How should the p-value be read?

General statistical explanation: A p-value is calculated under a null model, commonly one in which the true group difference is zero. It indicates how unusual data at least as discrepant as those observed would be under that model, subject to the analysis assumptions. It is not the probability that the null model is true, nor does it measure clinical importance. The posted unadjusted p-value is 0.915. The registry does not state an adjustment for multiple testing for this comparison.

The result is reported as a mean of a continuous measure, with the primary endpoint defined as change over time. The registry identifies randomized allocation and a parallel design, but does not report the detailed statistical model, the treatment of missing outcome measurements, or whether the displayed comparison used all randomized participants. The exact analysis population and handling of deviations from assigned activity are not reported in the registry record.

For planning, the posted illustrations use the observed effect and state assumptions of a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. They consider the stated fractions of the observed effect. These assumptions describe the planning illustration, not necessarily the trial’s original design. The original design assumptions and sample-size justification are not reported in the registry record. The planning figures are not observed power; they are hypothetical sample-size illustrations based on the stated assumptions.

10. Confidence Intervals and Precision

The estimated mean difference is 0.24 points, comparing habitual physical activity with aerobic exercise. Its confidence interval extends from -4.169 to 4.649. The interval includes zero and values on either side of it, so the direction of the underlying group difference remains uncertain. The estimate should not be interpreted as a precise measurement of a small difference simply because the point estimate itself is close to zero.

General statistical explanation: A confidence interval gives a range of estimates compatible with the observed data and the method’s assumptions. A narrower interval indicates greater precision; a wider interval indicates more uncertainty. The interval does not assign a probability to each possible value after observing the data. Its practical meaning depends on the outcome scale and on what differences would matter, and the registry does not report a threshold for a clinically important difference on this score.

The arm standard errors, 0.99 for aerobic exercise and 2.02 for habitual physical activity, also indicate that uncertainty differs between the reported arm means. They are not measures of individual variability. The registry does not provide the participant-level data or detailed analysis procedures needed to independently assess how the confidence interval was constructed.

The confidence interval and p-value are consistent in indicating that this result does not clearly separate the group contrast from zero. That is not the same as showing that the groups are equivalent. An equivalence conclusion would require an explicitly defined margin and an analysis designed to evaluate it; such a margin and analysis are not reported in the registry record. The breadth of the interval means the data leave uncertainty about both direction and magnitude.

11. 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 display gives hypothetical participants per arm for 80% power and participants per arm for 90% power. These are not total event counts: the outcome is continuous, and the figures are participants per arm. The registry’s planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set to the stated fraction of the observed effect. The planning figures are not observed power.

The 80% power column means the planned sample size would give an 80% chance of detecting the chosen effect under the stated assumptions if that effect were the true one. The 90% power column describes the corresponding sample size for a higher chance of detection under those assumptions. These are design probabilities for hypothetical studies, not probabilities that the result in this trial is correct or that an effect exists.

The planning illustration is based on the observed mean difference of 0.24. It lists 18,540 participants per arm for planning for 100% of the observed effect, 32,959 for planning for 75% of the observed effect, and 74,158 for planning for 50% of the observed effect at 80% power. For 90% power, it lists 24,819, 44,123, and 99,276 participants per arm for those respective effect assumptions. Smaller effects need more participants to detect under the same assumptions, which is why the figures rise as the planning effect becomes a smaller fraction of the observed one.

These large planning figures reflect the small observed contrast used in this illustration; they are not a recommendation for a future trial. They also do not describe the original trial’s design. The original sample-size justification and assumptions are not reported in the registry record. The illustration should be read as a sensitivity exercise based on the observed estimate, not as evidence about the trial’s power after completion.

12. 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 = 0.240; pooled standard deviation σ = 8.248.
2. n = 2 × (1.96 + 0.842)² × 8.248² / 0.240² = 18,539.3, rounded up to 18,540 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 <- 0.24                      # observed difference in means
sigma <- 8.24780862834555                     # 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(3641287)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 18,540 (80% power), 24,819 (90% power)
 75% of observed effect: n per arm = 32,959 (80% power), 44,123 (90% power)
 50% of observed effect: n per arm = 74,158 (80% power), 99,276 (90% power)
power.t.test: 18540.2 
Simulated power at n = 18,540 per arm: 0.800 (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.

13. Multiplicity, Missing Data and Analysis Populations

The registry lists seven outcome measures, but no secondary outcome results are posted in the results analyzed. It also reports zero analyses. The primary result described in this analysis is the mean change in the Physical Component Score. The trial’s title and brief description mention distress and biomarkers of angiogenesis and chronic stress, but results for those outcomes are not reported in the registry record. Their absence from the posted results does not establish whether they were collected, analyzed, or omitted for another reason.

Multiplicity concerns arise when several outcomes or comparisons are tested, because interpreting each test separately can increase the chance of at least one apparently unusual result. General statistical explanation: Researchers may plan a primary outcome, specify a testing hierarchy, or adjust for multiple comparisons. The registry record analyzed does not report a multiplicity strategy, so it is not possible to determine whether or how any such approach was used. The posted p-value is identified as unadjusted.

The record does not report how missing outcome measurements were handled, whether imputation was used, or whether analyses followed an intention-to-treat approach. It does not specify the analysis population for the primary comparison or describe exclusions after randomization. The outcome arm counts are 28 and 27, while the safety summaries use at-risk counts of 31 and 33. These are different reported counts for different summaries; the record does not explain their relationship or the reasons for any difference.

Details about adherence to assigned activity, protocol deviations, and the statistical model are also not reported in the registry record. These omissions limit assessment of the analysis process and of how representative the posted estimates are of all randomized participants. They do not, by themselves, indicate that any particular method was or was not used.

14. 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 safety summaries report zero serious adverse events in the aerobic-exercise group among 31 participants at risk and zero in the habitual-activity group among 33 participants at risk. They also report zero other adverse events in each group, using the same respective at-risk counts, and zero deaths in both groups. No serious adverse event terms are listed.

These figures describe the events recorded in the registry’s safety results. They do not show that no events of any kind occurred outside the categories or observation process represented by the registry report. The record does not provide event definitions, collection procedures, severity details beyond the serious/other categories, or the safety observation period in the information analyzed. It also does not explain how the safety at-risk counts relate to the primary outcome counts.

General statistical explanation: A zero count in a reported category is not proof that the underlying risk is zero. Rare events can be difficult to characterize, especially when the amount of safety information is limited. These safety summaries should therefore be read as the registry’s reported counts, not as a definitive comparison of safety between the assigned groups.

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

The registry reports a small positive mean difference of 0.24 points in change in the Physical Component Score, with the habitual-activity group as the first group in the contrast. The confidence interval, from -4.169 to 4.649, includes zero and extends in both directions. The unadjusted p-value is 0.915. Together, these results show that the posted estimate is uncertain and that the data do not clearly establish a difference between group mean changes.

This does not demonstrate equivalence. The record does not provide an equivalence margin or an analysis designed to establish that possible differences are small enough to be unimportant. Nor does the result prove that there is no effect: the interval allows a range of values, and the registry does not specify what change would be clinically important on this scale.

The primary result addresses one quality-of-life measure over baseline to 24 weeks. It cannot answer whether distress, fatigue, anxiety, or the named biomarkers changed, because those results are not reported in the registry record analyzed. It also cannot establish outcomes beyond the stated period. The trial was terminated, but the reason and any consequences for outcome collection are not reported in the registry record.

The assignment was randomized, but the available summary does not provide the full analysis plan, missing-data procedures, or participant-level outcomes. The finding should therefore be described narrowly: the posted group means were 4.37 and 4.61, and the estimated difference between them was 0.24 with substantial uncertainty. This statistical interpretation is not medical advice and does not determine what treatment or activity is appropriate for any individual.

16. Why This Trial Matters Statistically

This trial illustrates why a point estimate, its uncertainty, and the study context need to be considered together. The posted mean difference is 0.24, while its confidence interval ranges from -4.169 to 4.649. Focusing only on the point estimate could make the result appear more definitive than it is; focusing only on the p-value would also lose information about the range of compatible differences.

The endpoint is a standardized composite score rather than a direct count of symptoms or events. Understanding its scale matters for interpretation: the Physical Component Score ranges from 20 to 60, with higher scores indicating better quality of life, while the registry does not state what size of change would matter clinically. Without that threshold, statistical summaries cannot by themselves classify the observed contrast as meaningful or negligible.

The record also demonstrates the importance of distinguishing enrollment, outcome counts, and safety counts. Enrollment is 64, the primary outcome summaries list 28 and 27 participants, and the safety summaries list 31 and 33 at risk. These figures serve different purposes, and the registry does not explain their relationship. Treating them as interchangeable would obscure uncertainty about which participants contributed to each result.

Finally, the title identifies interests in distress and biomarkers, but the analyzed registry results contain no posted secondary outcome results. Statistical interpretation must remain tied to the result actually reported. The terminated status, missing analysis details, and lack of reported multiplicity and missing-data procedures all matter when judging how much can be learned from this single comparison.

17. 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 outcome summaries cover 28 participants in the aerobic-exercise arm and 27 in the habitual-activity arm, whereas the registry lists enrollment of 64. The record does not explain the difference or state the exact analysis population. The safety summaries use different at-risk counts, and their relationship to outcome participation is not reported. This makes it difficult to assess completeness of the primary outcome data from the registry entry alone.

The record identifies the study as terminated but does not report why it was terminated or whether termination affected follow-up, outcome collection, or analysis. It does not report the original sample-size justification, detailed statistical analysis plan, model specification, missing-data approach, or analysis population. The displayed planning illustration is based on the observed effect and should not be treated as evidence of the study’s original design adequacy.

The posted results focus on the primary quality-of-life measure. Although the trial record refers to distress and biomarkers, results for those outcomes are not reported in the registry record analyzed. The record also does not provide a clinically important difference threshold for the Physical Component Score, making it harder to judge practical importance from the numerical contrast alone.

The intervention description is incomplete at the end of its account of telephone-based motivational support. Details of actual exercise adherence and the extent to which participants followed assigned activity are not reported in the registry record. The identity of those masked, if any beyond the single-masked designation, is not stated. These limitations restrict interpretation of the reported group contrast without establishing that any particular design or analysis choice was inappropriate.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: The Effects of Exercise on Distress, Quality of Life, and Biomarkers in Ovarian Cancer Survivors — NCT03641287.
• Registry record last updated 2023-11-29; status last verified 2023-11.
• Results first posted 2023-11-29.
• 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.

21. Record Summary

The registry describes a randomized, single-masked, parallel-group trial of aerobic exercise versus habitual physical activity among people with ovarian, fallopian tube, or primary peritoneal cancer. Enrollment is 64, the listed phase is NA, and the record status is terminated. The registry lists a start date of 2018-12-05 and a primary completion date of 2022-09-30.

The primary endpoint is mean change from baseline to 24 weeks in the RAND 36-item Short Form Physical Component Score. The posted mean changes are 4.37 for aerobic exercise and 4.61 for habitual physical activity. The reported mean difference, comparing habitual activity with exercise, is 0.24, with a confidence interval from -4.169 to 4.649 and an unadjusted p-value of 0.915.

The record lists seven outcome measures but no posted secondary outcome results in the results analyzed. Safety summaries report zero serious adverse events, zero other adverse events, and zero deaths in both groups. The reason for termination, detailed analysis procedures, missing-data handling, and original sample-size assumptions are not reported in the registry record.