Acceptability of Active Monitoring (AM) as a Treatment Option for Ductal Carcinoma in Situ (DCIS): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Acceptability of Active Monitoring (AM) as a Treatment Option for Ductal Carcinoma in Situ (DCIS) (NCT03775213), a randomized na study. The primary outcome is Number of Participants Who Chose Active Monitoring (AM)..

2. Clinical Question

The question concerns the effect of adding AM to the options presented in a decision support tool on participants’ stated treatment choices. It is not a comparison of treatment outcomes or a test of the clinical effectiveness of active monitoring. The primary endpoint records a choice made during the study, not whether a participant subsequently received that option or experienced a health outcome.

The registry describes the study’s purpose as evaluating a decision support tool for patients diagnosed with DCIS. The primary outcome was recorded within a timeframe of up to 1 hour. The registry record does not report further details about how participants used the tool, the setting in which choices were made, or whether the recorded choice was later confirmed or changed.

3. Trial Design

The registry identifies this as a randomized, double-masked, parallel-group study. Participants explored one of two behavioral decision support tools. One tool presented standard treatment options for DCIS alongside active monitoring; the other presented standard treatment options without active monitoring. The intended contrast is therefore between two versions of decision support, rather than between clinical treatments administered to participants.

The study is listed as completed. The registry gives an enrollment of 322, a start date of 2021-10-12, and a primary completion date of 2022-01-31. For the primary outcome, the posted arm results give a denominator of 102 in each group. The registry record does not explain how the enrollment figure relates to the denominators reported for this outcome, or identify the analysis population used for the primary comparison.

The masking field is recorded as double, but the registry record does not describe who was masked or how masking was implemented in a study involving different versions of a decision tool. It also does not report the randomization procedure, allocation concealment, or details of the analysis plan. These details should not be inferred from the design labels alone.

The primary choice was recorded as a categorical response: AM, lumpectomy, lumpectomy with radiation, or mastectomy. For the stated analysis, those options were collapsed into AM versus non-AM. The listed timeframe was up to 1 hour. The registry lists Duke University as the sponsor and identifies the condition as DCIS.

4. Participant Flow and Accounting

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

Overall Study

Reasons for not completing this period:

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Who Chose Active Monitoring (AM)., measured over Up to 1 hour.

The primary endpoint is the number of participants who chose active monitoring (AM). Participants were presented with four response categories: AM, lumpectomy, lumpectomy with radiation, and mastectomy. For analysis, the response was treated as binary: choosing AM versus choosing any of the non-AM options. The registry gives the assessment timeframe as up to 1 hour.

This endpoint addresses the study’s decision-support question directly: whether AM was selected when it appeared among the options in the tool. A binary outcome makes the comparison about the proportion choosing AM, rather than about which specific alternative was chosen by those who did not select AM. It therefore does not distinguish among the three non-AM choices.

The posted results record 28 participants choosing AM in the group whose tool included AM, and 18 in the group whose tool did not include AM; each arm has a reported denominator of 102 for this endpoint. These are choices recorded in the study, not evidence about later treatment received, adherence, disease progression, or other clinical outcomes. The registry record does not report whether participants’ choices were followed over time or whether they changed after the study interaction.

Using a choice endpoint is appropriate to a study evaluating a decision support tool’s effect on stated preferences. Its interpretation must remain tied to that purpose: the endpoint measures the recorded choice in the study context, not the quality or clinical consequences of the choice.

7. Results Posted in the Registry

• Standard Treatment Options: 17.6% (18/102) versus 27.5% (28/102) on control; risk difference -9.8 percentage points (95% CI -21.2 to 1.6), risk ratio 0.64 (0.38–1.09); unadjusted two-proportion z-test p = 0.094.

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.

Number of Participants Who Perceived Active Monitoring as Risky.

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Standard Treatment Options: 16.7% (17/102) versus 17.6% (18/102) on control; risk difference -1.0 percentage points (95% CI -11.3 to 9.4), risk ratio 0.94 (0.52–1.73); unadjusted two-proportion z-test p = 0.853.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Standard Treatment Options and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants Who Chose Mastectomy.

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Standard Treatment Options: 14.7% (15/102) versus 13.7% (14/102) on control; risk difference 1.0 percentage points (95% CI -8.6 to 10.6), risk ratio 1.07 (0.55–2.10); unadjusted two-proportion z-test p = 0.841.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Standard Treatment Options and the control. The interval gives the range of effects that remain compatible with the data.

The secondary results that are posted concern whether participants perceived AM as risky and whether they chose mastectomy. Across these measures, the arm counts are close, and the reported comparison intervals include the null values for their respective effect scales. Taken together, the available secondary results do not add a clearly separated pattern of group differences to the primary finding.

This broad pattern is compatible with the primary result in the limited sense that the secondary comparisons do not provide a strong contrary signal. They do not independently confirm the primary result, either. The measures address different responses to the tools, and uncertainty in one outcome does not resolve uncertainty in another. The registered outcomes also include acceptability and change in self-perceived knowledge, but results for those measures are not reported in the registry record.

Secondary outcomes usually carry less evidential weight when many outcomes or comparisons are examined without a reported plan to account for multiplicity. As the number of statistical tests grows, the chance of at least one apparently notable result arising by chance can increase. The registry record does not report a multiplicity adjustment, a hierarchy of outcomes, or a prespecified strategy for interpreting the secondary comparisons. Their results should therefore be treated as exploratory rather than as definitive evidence.

The record lists 21 outcome measures and 8 analyses, but does not give enough detail to determine how all outcomes were analyzed or selected for reporting. The two posted secondary comparisons can describe the reported outcomes, but they cannot establish that unreported outcomes were null or that all planned analyses are represented. A complete interpretation would require the prespecified analysis plan and results for the other registered outcomes.

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

• Number of Participants Who Found the Treatment Option Acceptable.
• Number of Participants Who Perceived Active Monitoring as Risky.
• Number of Participants Who Chose Mastectomy.
• Change in Self-perceived Knowledge About DCIS.

9. Statistical Interpretation

10. Statistical Methods Explained

What does the risk difference describe?

A risk difference subtracts the event probability in one group from the event probability in another. Here the event is choosing AM, and the recalculated comparison is standard treatment options alone relative to standard treatment options plus AM. The estimate is -0.098. Its negative direction means that the recorded probability of choosing AM was lower in the standard-options-only group in this comparison. This is an absolute contrast; it is not a ratio and does not describe the relative size of the probabilities.

The confidence interval for the recalculated risk difference includes zero. Zero is the value corresponding to no difference between groups on this scale. An interval that spans zero indicates that the posted summary data are compatible with no difference as well as with differences in either direction. The interval should therefore be considered alongside the point estimate rather than replaced by it.

What does the risk ratio describe?

A risk ratio divides one group’s event probability by the other group’s probability. A value of 1 corresponds to equal probabilities. The registry’s reported primary risk ratio is 1.53, with a 95% confidence interval from .91 to 2.58. Because the interval includes 1, it includes the value corresponding to no relative difference. The analysis does not report a p-value. The ratio’s direction depends on the order of the groups, so it is important to read it alongside the reported group order rather than treating it as a direction-free statistic.

Risk differences and risk ratios answer related but distinct questions. The risk difference conveys an absolute contrast; the risk ratio conveys a relative contrast. Their numerical values cannot be directly compared because they are on different scales. Both can be useful descriptions, but neither eliminates uncertainty in the observed comparison.

What does the unadjusted p-value mean?

The recalculated primary comparison has an unadjusted p-value of 0.094. A p-value describes how unusual data at least as discrepant as those observed would be under a specified null model and its assumptions. It is not the probability that the null hypothesis is true, and it does not measure the chance that the finding will replicate. The term unadjusted indicates that this result is not adjusted for multiple comparisons; the registry record does not report a multiplicity procedure.

Statistical significance is not a substitute for effect size or precision. The point estimate, confidence interval, analysis definition, and study context all matter. In this case, the point estimate indicates a directional difference, while the interval includes the null value. The p-value should not be interpreted as proof that the groups are identical or proof that they differ.

Why does the binary coding matter?

The original choice categories included AM, lumpectomy, lumpectomy with radiation, and mastectomy. The primary analysis combines the last three into a single non-AM category. That coding focuses the analysis on whether AM was selected, but it discards distinctions among the alternative choices. A change in the AM count cannot reveal which non-AM option participants might otherwise have selected.

The outcome is a count of participants with the event, not a continuous measurement. There is no reported measure of dispersion such as a standard deviation for this binary endpoint. The relevant uncertainty is instead expressed through the comparison’s confidence interval and test result.

What can be said about the analysis choices?

The registry records a randomized, double-masked, parallel design, but does not report the statistical method used for the sponsor’s analysis, the trial’s prespecified statistical plan, or the analysis population. The recalculated comparison is an unadjusted calculation from the posted summary counts. It should not be mistaken for an adjusted model or for the sponsor’s full analysis. Since the discrepancy indicator is false, there is no stated discrepancy requiring the sponsor analysis to take precedence; the two analyses should still be distinguished by their effect measures and reported details.

Randomization is intended to support comparisons between groups, but the registry entry alone does not establish how allocation was generated or concealed, whether the analysis followed the random assignment, or how incomplete outcomes were handled. Those procedural and analytic details are not reported in the registry record. They limit the ability to assess the assumptions underlying the comparison.

11. Confidence Intervals and Precision

Precision describes how narrowly the data estimate the underlying group contrast. A confidence interval gives a range of values compatible with the data under the method used to construct it. It is not a guarantee that the true value lies in the interval, and it does not describe the range of individual participants’ choices.

For the primary risk difference, the recalculated confidence interval includes zero, the value corresponding to no difference on this scale. This means the interval allows both a difference in one direction and a difference in the other direction, as well as no difference. The point estimate of -0.098 is therefore not precise enough by itself to settle the direction or magnitude of the underlying contrast.

The registry’s primary risk ratio has a 95% confidence interval from .91 to 2.58. Since this interval includes 1, it also spans the null value, this time on the ratio scale. The interval is broad enough to be consistent with relative effects on either side of no difference. This is another way of expressing uncertainty, not a separate experiment or independent confirmation.

The denominators reported for the primary endpoint are 102 in each arm, and the observed event counts are 28 and 18. With binary outcomes, the precision of a group comparison depends on the number of observations and the event frequencies, among other assumptions. A modest number of observed events can leave substantial uncertainty around a difference even when the point estimates are not identical.

Confidence intervals do not establish that a meaningful difference is absent when they include the null. They show that the data do not pin down the effect narrowly enough to exclude the null under the reported calculation. The registry does not report a prespecified threshold for a practically important change in AM choice, so the clinical or decision relevance of particular values within the interval cannot be assessed from this record alone.

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 sample-size figures are planning illustrations based on the observed primary effect, not the original trial design calculation. They are participants per arm, not total participants or total events. The listed assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is the stated fraction of the observed effect. The trial’s own original design assumptions are not reported in the registry record.

For planning at 100% of the observed effect, the illustration gives 285 participants per arm for 80% power and 380 participants per arm for 90% power. At 75% of the observed effect, the corresponding figures are 525 participants per arm for 80% power and 703 participants per arm for 90% power. At 50% of the observed effect, they are 1,224 participants per arm for 80% power and 1,638 participants per arm for 90% power.

In plain terms, a design with 80% power under the stated assumptions would have an 80% chance of detecting the specified effect if that effect were the true one and the assumptions held. A 90% power target raises that chance to 90%, generally requiring more participants. The columns are alternative planning targets, not descriptions of what happened in the completed study.

The effect fractions represent progressively smaller effects. Smaller effects are harder to distinguish from random variation and therefore require more participants for the same power target. The figures are not observed power and do not measure the probability that the study’s result is correct. They are illustrations tied to the observed effect and the listed assumptions, not a substitute for a prospective design justification.

The record does not report the original sample-size justification or whether the study was designed around the primary endpoint, a different outcome, or another objective. The planning figures should therefore be read as a separate, retrospective illustration rather than evidence about the study’s original planning process.

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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.275; treatment proportion p₁ = 0.176; average p̄ = 0.225.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.5910 = 1.1584.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.5869 = 0.4940.
4. n = (1.1584 + 0.4940)² / (-0.0980)² = 284.0, rounded up to 285 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
p0 <- 0.274509803921569                          # control proportion
p1 <- 0.176470588235294                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^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 (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(3775213)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 285 (80% power), 380 (90% power)
 75% of observed effect: n per arm = 525 (80% power), 703 (90% power)
 50% of observed effect: n per arm = 1,224 (80% power), 1,638 (90% power)
power.prop.test: 284 
Simulated power at n = 285 per arm: 0.805 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-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. Analyses Reported by the Sponsor

The registry reports the sponsor’s primary analysis as a risk ratio of 1.53 with a 95% confidence interval from .91 to 2.58. The reported group order is the tool with standard treatment options plus AM followed by standard treatment options alone. The direction of this estimate is consistent with the posted counts, which show more AM choices in the group whose tool included AM. The confidence interval includes 1, the null value for a risk ratio.

The recalculated analysis uses the posted summary counts and expresses the comparison as a risk difference for standard treatment options alone relative to standard treatment options plus AM. Its estimate is -0.098, with an unadjusted p-value of 0.094; its confidence interval includes zero. The risk ratio and risk difference are different measures, so their numerical estimates are not expected to match.

The discrepancy indicator is false. The posted analyses therefore do not carry a flagged disagreement, although the registry’s analysis and the unadjusted recalculation remain distinct calculations with different effect measures and reporting detail. The registry does not state the method for the sponsor analysis or give its p-value. The recalculation cannot supply those missing details or be treated as a replacement for the sponsor’s analysis.

Both results should be interpreted as comparisons of recorded AM choice after exposure to the decision tools. Neither analysis addresses clinical outcomes or the later course of care.

15. Multiplicity, Missing Data and Analysis Populations

The registry record lists multiple outcome measures and analyses, including a primary choice outcome and several secondary outcomes. It does not report whether the investigators adjusted for multiple testing, defined a hierarchy among outcomes, or specified which comparisons would be treated as confirmatory. Without those details, the secondary results should be interpreted cautiously. Multiple testing can increase the chance of at least one apparently unusual result when many comparisons are considered.

The record also does not report the amount or pattern of missing outcome data, how missing responses were handled, or whether participants with incomplete data were excluded or included under a particular method. The registry gives an enrollment of 322, while the primary outcome results list denominators of 102 in each arm. The record does not explain this relationship, so it is not possible to identify from the posted information whether the outcome denominators reflect a defined analysis subset, incomplete outcome reporting, or another process.

The analysis population is not reported in the registry record. In particular, the entry does not state whether the primary comparison followed the randomized assignment for all participants, used only participants who completed the decision task, or applied another inclusion rule. The potential effects of exclusions or missing responses therefore cannot be evaluated from the summary counts alone.

Other important analysis details are also not reported, including the randomization procedure, allocation concealment, the sponsor analysis method, and a prespecified statistical analysis plan. The design is labeled randomized and double-masked, but those labels do not provide the missing procedural detail. These omissions do not invalidate the posted results, but they limit independent assessment of selection, missing-data, and analysis choices.

The record lists secondary outcomes for acceptability and self-perceived knowledge, but their results are not reported in the registry record. Their absence should not be interpreted as evidence that no difference was observed. It leaves the overall pattern of responses incomplete.

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

The primary results describe a choice made after participants explored one of two decision support tools. More participants in the group whose tool included AM chose AM than in the group whose tool omitted it. The recalculated estimate points in that direction, but its confidence interval includes no difference, and the sponsor-reported ratio interval includes its own null value. The data therefore do not provide a precise estimate that excludes no difference.

This is evidence about how the options presented in a decision support tool related to participants’ recorded choices in the study. It is not evidence that active monitoring or another treatment option improves health, is safer, or is preferable. The study did not report treatment outcomes in the posted results. No conclusion about disease progression, survival, quality of life, or later clinical decisions can be drawn from the primary endpoint.

The result also does not show that a participant who selected AM would maintain that preference or receive that care. The outcome was recorded within a timeframe of up to 1 hour, and the registry record does not report follow-up of the choice. Nor does the binary outcome reveal which alternative participants would choose if they did not select AM, because lumpectomy, lumpectomy with radiation, and mastectomy are grouped together as non-AM.

A confidence interval that includes the null does not prove that the tools have identical effects. It indicates that the posted estimate remains uncertain and compatible with no difference under the calculation used. Conversely, the direction of the point estimate alone does not establish a reliable effect. The interpretation needs to account for the interval, the small number of reported endpoint observations relative to the enrollment figure, and the unavailable details about missing data and analysis population.

The study is best understood as evaluating an immediate decision-support response in a specific study context. Its results may inform discussion of how the presentation of options relates to recorded choices, but the registry record does not provide enough detail to generalize beyond that context or infer clinical consequences.

17. Why This Trial Matters Statistically

This study illustrates a useful statistical distinction between a decision process and a clinical outcome. The primary endpoint is a participant’s recorded selection among treatment options, not a measure of what happened after treatment. Keeping that distinction clear prevents a choice result from being overstated as evidence about treatment benefit or harm.

It also shows why effect measures and uncertainty need to be read together. The recalculated risk difference and the sponsor-reported risk ratio point in a consistent direction, but they describe the comparison on different scales. Their intervals include the respective null values. The point estimates alone therefore give an incomplete account of what the data can establish.

The endpoint’s binary coding is another important design choice. It makes the primary question straightforward—whether AM was selected—but it combines three distinct alternatives into one category. That is appropriate for the stated primary question, while limiting what the outcome can say about the broader choice process. A complete interpretation needs to account for what the coding preserves and what it leaves out.

The record also highlights the importance of transparent reporting. Although enrollment, outcome counts, and a sponsor analysis are posted, the analysis population, missing-data handling, statistical plan, and multiplicity approach are not reported in the registry record. Without them, readers cannot fully assess how the available results relate to all enrolled participants or how the secondary findings were selected and interpreted.

Finally, retrospective planning illustrations based on an observed effect should not be confused with prospective sample-size justification. They can help explain how detectable effect size and power relate, but they do not establish what the study was designed to detect. Clear separation of those purposes supports sound interpretation of both trial findings and future planning.

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.

The registry record provides limited detail about the study population. It identifies DCIS as the condition but does not report further eligibility criteria or participant characteristics. This constrains assessment of how broadly the choice findings apply. The study is described as randomized and double-masked, but details of random sequence generation, allocation concealment, and implementation of masking are not reported in the registry record.

The relationship between the enrollment figure and the primary outcome denominators is not explained. The outcome results list 102 participants in each arm, while the registry enrollment is 322. Without information about participant flow, outcome completion, or the analysis population, it is not possible to determine how the reported counts relate to the full enrolled group. Missing-data methods and reasons for any absent outcomes are also not reported.

The endpoint is an immediate stated choice, with a timeframe of up to 1 hour. The record does not report whether choices were later confirmed, changed, or followed by treatment. The binary coding also combines lumpectomy, lumpectomy with radiation, and mastectomy, so the primary result does not describe how choices among those alternatives differed.

Only two of the listed secondary outcomes have posted results. Acceptability and change in self-perceived knowledge are listed, but their findings are not reported in the registry record. The statistical plan and approach to multiple comparisons are also not reported, making it difficult to assess whether the available secondary findings reflect a prespecified analysis strategy.

Finally, the registry does not report the original sample-size justification or the method used for the sponsor’s analysis. The posted planning illustrations are based on the observed effect and should not be treated as evidence of the original design assumptions. These limitations concern the information available in the registry record and should not be filled in by inference.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Acceptability of Active Monitoring (AM) as a Treatment Option for Ductal Carcinoma in Situ (DCIS) — NCT03775213.
• Registry record last updated 2023-01-30; status last verified 2023-01.
• Results first posted 2023-01-30.
• 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 identifies NCT03775213 as a completed, randomized, double-masked, parallel study sponsored by Duke University. Its purpose was to evaluate a decision support tool for DCIS. One tool included standard treatment options and active monitoring; the comparator included standard treatment options without active monitoring. Enrollment is listed as 322, with a start date of 2021-10-12 and a primary completion date of 2022-01-31.

The primary outcome was the number of participants choosing AM, recorded as AM versus non-AM within up to 1 hour. The posted results report 28 choices among 102 participants in the tool group that included AM, and 18 among 102 in the group without AM. The recalculated risk difference is -0.098, with an unadjusted p-value of 0.094 and a confidence interval that includes zero. The registry reports a risk ratio of 1.53 with a 95% confidence interval from .91 to 2.58.

The record lists secondary outcomes concerning acceptability, perceived risk, mastectomy choice, and self-perceived knowledge. Results are posted for perceived risk and mastectomy choice; results for acceptability and knowledge change are not reported in the registry record. Details about the analysis population, missing data, and multiplicity are also not reported.