Management of Cognitive Difficulties After Cancer Treatments in Women Treated for Breast Cancer: Feasibility Study (Step 1 of the Cog-Stim Protocol): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Management of Cognitive Difficulties After Cancer Treatments in Women Treated for Breast Cancer: Feasibility Study (Step 1 of the Cog-Stim Protocol) (NCT04213365), a na na study. The primary outcome is Patient Adherence.

2. Clinical Question

3. Trial Design

This was a completed, longitudinal, single-group feasibility study sponsored by Centre Francois Baclesse. The registry lists 20 participants, a single intervention group, allocation as NA, and masking as none. The intervention was cognitive stimulation coupled with adapted physical activity. The arm description specifies a 12-week program. The registry gives a study start date of 2020-01-24 and a primary completion date of 2021-11-02.

The study’s stated purpose was to assess adherence to, and the feasibility and acceptability of, the combined program. The description places the work within a broader interest in managing cognitive difficulties after breast cancer treatment, including approaches that use cognitive stimulation, adapted physical activity, or both. However, the registered study itself is not a randomized comparison of those approaches. It describes one group receiving the combined intervention, so the stated broader research aims should not be mistaken for comparisons conducted in this feasibility study.

Feasibility is a different question from comparative effectiveness. A feasibility study can examine whether participants undertake the planned sessions and how acceptable they find a program. It does not, by itself, establish whether the program changes cognitive difficulties or whether it performs better than another approach. The registry record does not report a control group, random assignment, or masking. It also does not report a detailed statistical analysis plan or a rationale for the enrollment target. Those design details are not reported in the registry record.

The study is marked completed, but that status does not provide the numerical outcome results. The record lists the primary endpoint and secondary outcomes, yet does not report their findings. In particular, completion status alone cannot establish the proportion reaching the adherence threshold, participant acceptance, or satisfaction. The posted design should therefore be read as a one-group feasibility assessment, with outcome interpretation limited by the results available 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.

Before assignment: Eligible patients were women with localized breast cancer who were starting or currently undergoing adjuvant radiotherapy, with or without prior adjuvant chemotherapy, who had not yet initiated hormone therapy, were older than 18 years, and reported cognitive complaints with a significant impact on their quality of life.

Overall Study

Analysis population for the primary outcome, as defined in the registry: All included patients were analysed for the primary endpoint.

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 Patient Adherence, measured over Between inclusion and 3 months.

The primary endpoint is titled Patient Adherence and is described as the proportion of patients who completed cognitive stimulation sessions coupled with adapted physical activity sessions. The timeframe is between inclusion and 3 months, and the registry states that all included patients were analysed for this endpoint. Although the outcome unit is listed as participants, its description defines an adherence proportion based on participants’ completion of the program.

The completion rules are specific. A cognitive or physical training session counted as performed if at least 70% of that session was completed: at least 14/20 min for a cognitive session and 20/30 min for an adapted physical activity session. For a given week, adherence required completion of all four planned sessions. High adherence to the 12-week multimodal program was defined as completing at least 9 weeks.

These operational rules turn a broad concept—adherence—into a threshold that can be assessed consistently. They also distinguish completing an individual session from meeting the weekly and overall program criteria. The endpoint is appropriate to the stated feasibility focus because it concerns whether participants completed the planned activities. It is not a direct measure of cognitive improvement, nor does it compare the combined program with another treatment. The number meeting the high-adherence definition and the resulting proportion are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registered primary outcome is an adherence measure with a threshold-based definition. Understanding that definition is essential because “adherence” can mean different things unless the activities, completion rules, and assessment period are specified. In this study, an individual training session counted as performed only if at least 70% of the session was completed. The specified cutoffs were at least 14/20 min for cognitive stimulation and 20/30 min for adapted physical activity. A week counted as adherent only when all four planned sessions were completed. High adherence to the 12-week program meant completing at least 9 weeks.

What does a threshold-based endpoint capture?

A threshold-based endpoint classifies participants according to whether they meet a prespecified criterion. This can make a feasibility question easier to interpret: the outcome concerns the proportion who achieved the defined level of program completion. It also compresses detailed session-by-session behavior into a yes-or-no classification for the high-adherence outcome. That summary can be useful, but it does not show how close participants who did not meet the threshold came to it, or how completion varied across weeks. Those details are not reported in the registry record.

The distinction between session, week, and program criteria matters. Completing part of a session is not necessarily enough to count that session as performed; the stated minimum is at least 70%. A week requires all four planned sessions, rather than an unspecified share of them. The overall high-adherence definition then uses a minimum number of completed weeks. These nested rules define how individual activities contribute to the overall endpoint. The registry record supplies the rules but not the participant-level completion pattern or the final endpoint result.

How would a proportion be interpreted?

In general, a proportion expresses the number meeting a specified condition relative to the relevant group. For this endpoint, the condition is meeting the high-adherence definition, and the population is the included patients. A proportion is informative only alongside a clear denominator and an observed count. The record states that all included patients were analysed for the primary endpoint and lists enrollment of 20, but it does not report how many met the adherence criterion. The endpoint proportion itself is not reported in the registry record, and no estimate should be inferred from the definition or enrollment alone.

In general, uncertainty around an estimated proportion can be described with a confidence interval. A confidence interval communicates how precisely the data estimate an underlying quantity, subject to the assumptions of the method used. It is not a guarantee that the true value lies within the interval, and it does not remedy a missing outcome result. No confidence interval or primary adherence estimate is reported in the registry record. Without the endpoint result, readers cannot assess either its magnitude or its statistical precision.

What does the single-group design imply?

A single-group study can describe what happened among participants who received the program, provided the relevant outcomes are reported. It does not provide a concurrent comparison group for estimating how outcomes would have differed under another approach. This distinction is especially important when the broader rationale mentions multiple possible management strategies. The registered study’s combined intervention is not a randomized head-to-head evaluation of cognitive stimulation alone, adapted physical activity alone, and their combination. The allocation field is recorded as NA, and the study model is single group.

Masking is listed as none. Masking generally refers to keeping participants, investigators, or outcome assessors unaware of assigned treatment, where applicable. A single-group study without masking does not have treatment assignments to conceal in the manner of a masked comparative trial. The record does not describe additional procedures to limit measurement or reporting bias. That absence of detail should not be filled in by assumption.

How should planning illustrations be distinguished from trial design?

The registry’s sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustration is explicitly distinct from the trial’s own design. Equal allocation between two arms does not describe this study’s registered single-group enrollment. The registry record does not report the effect value used in such an illustration or the resulting sample-size figures, and it does not report a sample-size justification for the feasibility study. A planning illustration is not an observed outcome and is not evidence that the study had a particular level of power. Sample-size calculations are planning tools, not substitutes for reported results.

More generally, a significance level specifies a threshold used in a hypothesis-testing procedure, while a power calculation concerns the chance that a planned test detects a specified effect under stated assumptions. Those concepts require a defined comparison and effect. For this study, no randomized comparison is registered, and no primary adherence estimate or analysis is reported. The stated planning assumptions therefore should not be interpreted as a description of an analysis actually conducted.

Finally, statistical methods cannot recover information that is absent from the posted results. The registry record lists no analyses and does not give an analysis method for the primary or secondary outcomes. It does not report inferential tests, confidence intervals, adjusted estimates, or a statistical analysis plan. The methods that can be interpreted are therefore the endpoint definitions and the single-group design, rather than a reported statistical comparison.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Cognitive Stimulation and Adapted Physical Activit")
n      <- c(20)
events <- c(11)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Cognitive Stimulation and Adapted Physical Activit  20  11  55.0  31.5  76.9  34.2  74.2  34.0  74.3

11. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when a study evaluates more than one outcome or performs multiple statistical tests. In general, interpreting several tests as though each were the only test can increase the chance of a false-positive finding across the set. A statistical plan may specify which outcome is primary, which outcomes are secondary, and whether or how testing is adjusted. The registry lists Patient Adherence as the primary endpoint and lists Proportion of Acceptance and Patient Satisfaction as secondary outcomes. A plan for handling multiplicity is not reported in the registry record.

The record lists no analyses, and it does not report results for the primary or secondary outcomes. Therefore, there are no reported tests or estimates from which to assess the practical consequences of multiplicity. The existence of multiple listed outcomes does not establish that formal hypothesis tests were conducted. Nor does the absence of listed analyses establish what investigators may have planned outside the registry record.

Missing-data methods are also not reported in the registry record. The record states that all included patients were analysed for the primary endpoint, but it does not describe whether all outcome observations were available, how unavailable session information was treated, or whether any imputation or sensitivity analysis was used. “All included patients were analysed” describes the stated analysis population; it does not by itself establish complete outcome ascertainment or explain the handling of missing observations.

The analysis population for the primary endpoint is identified as all included patients. Further analysis-population definitions, such as a separate per-protocol group, are not reported in the registry record. Because adherence itself concerns completion of program activities, the distinction between inclusion in the analysis and completion of the intervention is important: participants can belong to the analysis population without necessarily meeting the high-adherence threshold.

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 1% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists one intervention group with 20 participants at risk for serious adverse events and 20 at risk for other adverse events. It reports 0 participants affected by serious adverse events, 2 affected by other adverse events, and 0 deaths. These are the posted counts for the group; they do not provide a detailed account of event type, timing, severity beyond the serious-versus-other classification, or causal relationship to the intervention.

No serious adverse-event terms are listed. The record does not report further descriptions of the 2 other adverse events. The counts should therefore be read narrowly as registry safety figures, not as a complete narrative of individual events. In general, an event recorded during a study is not necessarily caused by the intervention; attribution requires information that is not reported in the registry record.

The group counts also do not permit comparison with an untreated or alternative-treatment group, because the registered design is single group. The record’s safety figures describe the listed participants at risk in the intervention group and should not be interpreted as comparative evidence. They also do not replace the feasibility outcomes: the primary endpoint concerns adherence, while safety counts address reported adverse events.

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

The study addresses an important practical question: can women treated for breast cancer undertake a program that combines cognitive stimulation and adapted physical activity? Its design focuses on feasibility, with adherence as the primary endpoint and acceptance and satisfaction listed as secondary outcomes. The session and weekly completion rules make the intended adherence construct explicit. That provides a clear framework for assessing whether participants completed the planned program, if the corresponding outcome results are available.

The registry record does not report those results. It gives no count or proportion for participants meeting the high-adherence definition, and it does not report acceptance or satisfaction results. Therefore, the posted results do not establish the level of adherence, acceptance, or satisfaction. The study’s completed status does not fill that gap.

Even with outcome values, adherence would answer a feasibility question, not necessarily a clinical-benefit question. Completing sessions is not the same as demonstrating improvement in cognitive difficulties. The record does not report a cognitive outcome result that can be used to assess such improvement. And because the registered study has one group, it cannot provide a like-for-like comparison of the combined program against cognitive stimulation alone, adapted physical activity alone, or another control condition.

The study should therefore be understood as a feasibility evaluation with explicitly defined completion criteria, rather than as a comparative trial of treatment effects. Its registry record identifies what the primary endpoint was intended to measure and the group in which it was assessed. But the outcome values needed to judge feasibility are not reported in the registry record. No conclusion about program effectiveness, superiority, or lack of benefit follows from the information posted.

14. Why This Trial Matters Statistically

Feasibility questions are important when an intervention requires participants to complete repeated activities. The combined program described in this record includes cognitive stimulation and adapted physical activity, with planned sessions across a 12-week period. Before a larger evaluation can be interpreted, it can be useful to know whether participants can complete the planned activities and whether the program is acceptable. This study’s stated focus on adherence, acceptance, and satisfaction reflects that practical concern.

The endpoint definition also illustrates why operational details matter in clinical research. A label such as adherence is not self-explanatory. Here, the record specifies when an individual session counted as performed, what was required for a week to count, and how many weeks were needed for high adherence. Those rules clarify the target measure and make it possible to distinguish partial session completion from meeting the overall program criterion.

At the same time, statistical interpretation depends on reported results as well as definitions. A well-defined endpoint cannot show how participants performed if its count or proportion is absent. The registry record does not report the primary adherence result or the secondary outcome results. This limits the record’s value for judging feasibility, despite the detail in the endpoint rules.

The single-group design is also statistically important. It fits a feasibility question focused on experience within the intervention group, but it does not support a direct comparison among the different approaches discussed in the broader rationale. Separating feasibility from comparative effectiveness helps prevent overinterpretation: the purpose and design determine which questions the study can answer. In this case, the record identifies the feasibility question but does not post the outcome values needed to answer it.

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.

Several limitations are specific to the information registered for this study. The most consequential is that the primary adherence result is not reported in the registry record. The record defines high adherence and states that all included patients were analysed, but does not give the number meeting the criterion or the resulting proportion. The secondary outcomes, Proportion of Acceptance and Patient Satisfaction, are listed without reported results.

The registered design is single group, with allocation recorded as NA and masking as none. There is no like-for-like control comparison in the record. The intervention is the combined cognitive stimulation and adapted physical activity program; the broader description of other approaches does not make this study a direct comparison of those approaches. The record therefore cannot support comparative conclusions.

The endpoint is based on session and week completion thresholds. Although those definitions are specified, the record does not report the distribution of session completion, variation in adherence across weeks, or the number of participants near but below the high-adherence threshold. Such detail would help characterize feasibility beyond a binary classification, but it is not reported in the registry record.

Further limitations concern reporting and analysis. A statistical analysis plan, methods for handling missing outcome information, and multiplicity procedures are not reported in the registry record. The record lists no analyses. It also does not report a sample-size justification for the study. The planning assumptions described for an illustration do not describe the registered single-group design or establish its precision. Finally, detailed participant characteristics and further eligibility information are not reported, limiting assessment of how broadly the findings might apply even if outcome results were available.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Management of Cognitive Difficulties After Cancer Treatments in Women Treated for Breast Cancer: Feasibility Study (Step 1 of the Cog-Stim Protocol) — NCT04213365.
• Registry record last updated 2026-07-02; status last verified 2026-06.
• Results first posted 2026-07-02.
• 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

NCT04213365 is a completed, single-group feasibility study sponsored by Centre Francois Baclesse. It lists an enrollment of 20 and evaluates cognitive stimulation sessions coupled with adapted physical activity sessions in women treated for breast cancer. The arm description specifies a 12-week program. Allocation is recorded as NA, and masking as none.

The primary endpoint is Patient Adherence, assessed between inclusion and 3 months. High adherence was defined as completing at least 9 weeks, with session and weekly completion rules specified in the registry record. Proportion of Acceptance and Patient Satisfaction are listed as secondary outcomes.

The registry record does not report numerical results for the primary or secondary outcomes, statistical analyses, or methods for missing data. Safety counts list 0 serious adverse events, 2 other adverse events, and 0 deaths in the intervention group. The single-group design does not provide a like-for-like control comparison.