CairnSurgical Breast Cancer Locator (BCL) Post-Market Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for CairnSurgical Breast Cancer Locator (BCL) Post-Market Study (NCT06461663), a na na study. The primary outcome is Positive Margin Rate.

2. Clinical Question

In practical statistical terms, this is a descriptive question about the outcome observed in a treated group. Without a concurrent comparison group, the study cannot directly estimate how the margin outcome would differ under another surgical approach. Its design can describe the result among the participants analyzed, but attributing any result specifically to the device would require evidence beyond a single-group comparison.

3. Trial Design

This is a completed interventional post-market study of the Breast Cancer Locator during breast-conserving surgery. The registry lists 35 participants enrolled and describes the investigation as multicenter. The study start date is 2022-06-22, and the primary completion date is 2024-04-19. The study status is completed.

The design is single-group: participants underwent breast-conserving surgery with the Breast Cancer Locator. The masking field is NONE, and allocation is listed as NA. There is no randomized or concurrent control group described in the registry record. The treatment arm is titled Treatment With BCL.

The study’s brief description identifies the population as subjects with non-palpable breast cancer in Europe. The primary outcome description refers to partial mastectomy and pathology results from the index procedure. It specifies that pathology results were available within 14 days from the day the sample arrived at the pathological laboratory as the outcome timeframe.

The record lists five outcome measures and one analysis. Alongside positive margin rate, the listed secondary outcomes are specimen volume, surgeon’s perception, number of participants with adverse events, and patient satisfaction. Results for these secondary measures are not reported in the registry record. The record identifies the study as a post-market investigation of a custom-made medical device; it does not report a study phase beyond NA.

A single-group post-market design can provide descriptive information about outcomes observed with the device in the enrolled study population. It does not, by itself, separate the device’s contribution from other factors involved in surgery or establish how outcomes would compare under a different approach. The registry record does not report a protocol-level statistical plan, a sample-size justification, or a comparative design.

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: After signing the informed consent form, each subject entered a screening phase, during which several assessments (e.g., demographics, medical history, evaluation of available prone MRI and core biopsy pathological results) were conducted. Blood samples were also collect. A total of 45 patients were screened; however, 6 patients were excluded due to screening failure and 4 patients because surgery could not be performed with BCL. All remaining 35 patients were treated with BCL.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Participants analyzed were in the Per Protocol Set (PPS), which included all participants who (a) met all inclusion/exclusion criteria liable to affect the performance assessment, and (b) did not present serious deviations of the protocol that could affect efficacy. Two participants with serious deviations (BCL was not used properly) were not included in this analysis.

5. Baseline Characteristics

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

6. Primary Endpoint

The registry lists the primary outcome as Positive Margin Rate, measured over Pathology results from the index procedure available within 14 days from the day of sample arrival at the pathological lab..

The primary endpoint is positive margin rate, described as the proportion of participants with positive margins after partial mastectomy with the Breast Cancer Locator. The unit is participants, and the outcome is recorded as a count of participants. The stated timeframe is based on pathology results from the index procedure that were available within 14 days from the day the sample arrived at the pathological laboratory.

A margin outcome is used to describe whether pathology identifies cancer at the edge of the removed specimen. In this study, the endpoint focuses on the proportion of the analyzed group with a positive margin after surgery. As a general statistical concept, a proportion expresses how often an event occurs in a defined group; its interpretation depends on knowing both the event count and the number of participants included in the analysis.

The registry says the endpoint was intended to evaluate device performance in reducing the positive margin rate. That wording describes the study objective, not a demonstrated effect. The positive-margin count, denominator for the primary analysis, estimated proportion, and uncertainty interval are not reported in the registry record. The record’s primary population description identifies a Per Protocol Set, but it is truncated after mentioning two participants with serious deviations. Accordingly, the available record does not establish the analyzed denominator or allow the primary outcome to be quantified.

Because the design has one treatment group, a positive margin result could describe the observed outcome in that group, but it would not itself show how the result compares with an alternative surgical approach. A comparative interpretation would require a comparator and suitable analysis, neither of which is reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies positive margin rate as a binary outcome measured as a count of participants. A binary outcome has two possible states for each participant, such as positive margin or not positive margin. A count can be converted into a proportion only when the analysis denominator is known. Here, neither the primary outcome count nor the final analyzed denominator is reported in the registry record.

What does a single-group analysis describe?

In general, a single-group analysis describes outcomes among participants who received the intervention. It does not estimate a direct treatment contrast unless an appropriate comparison group or external benchmark is incorporated. The registry lists one group receiving Breast Cancer Locator-guided breast-conserving surgery and does not report a control group. Therefore, even a reported positive-margin proportion would describe the treated group, rather than establish how that outcome differs from another approach.

The distinction between description and comparison matters because an observed outcome can reflect multiple features of the study population, procedure, clinical setting, and outcome assessment. A randomized comparison can help evaluate differences between groups under its design and analysis assumptions. No randomized comparison is described in this record; allocation is listed as NA, and the study model is single group.

What does a count or proportion communicate?

As a general statistical concept, a count states how many participants experienced an event. A proportion relates that count to the number assessed. A proportion is interpretable only with a clear denominator and consistent outcome definition. The registry’s endpoint description gives the outcome definition and timeframe, but the outcome result and analyzed denominator are not reported in the registry record.

Uncertainty is also important. A confidence interval is a general method for showing a range of values compatible with the data under a statistical model. A narrow interval usually indicates greater precision than a wide interval, while neither width nor location alone resolves design limitations. No confidence interval for the primary outcome is reported in the registry record. Without a result and interval, readers cannot assess the magnitude or precision of the endpoint.

What can be inferred from the planning assumptions?

The registry includes assumptions for planning illustrations: a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a fraction of the observed effect. It describes sample-size outputs as participants per arm for most outcomes, while time-to-event illustrations use a total event count. These are general planning concepts, not a report of the design used for this single-group study.

A sample-size illustration asks how many participants might be needed under specified assumptions to detect a chosen effect with a chosen statistical operating target. The result depends on those assumptions and on the effect used for planning. Such an illustration is not observed power and does not establish whether a study result is statistically persuasive. The registry record does not report the observed primary effect or the resulting sample-size illustration values, so no numerical planning conclusion can be drawn.

Why does over-dispersion matter in general?

Over-dispersion is a general concern when count outcomes vary more than a chosen statistical model expects. If the model understates variability, standard errors may be too small and uncertainty intervals may be too narrow. This concept can matter for count data, but the primary endpoint is described as a participant count for a binary outcome, and the registry does not report an over-dispersion analysis or a model accounting for it. No conclusion about its use in this study can be made.

What does the listed analysis count tell readers?

The record lists one analysis and five outcome measures. Those counts do not specify which statistical tests, models, adjustment methods, or sensitivity analyses were used. The statistical plan is not reported in the registry record. General concepts such as significance testing, confidence intervals, and model assumptions explain how analyses may be interpreted, but they should not be mistaken for procedures confirmed in this study.

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("Treatment With BCL")
n      <- c(33)
events <- c(2)
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  Treatment With BCL  33  2  6.1  0.7  20.2  1.7  19.6  1.9  19.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists five outcome measures: positive margin rate, specimen volume, surgeon’s perception, number of participants with adverse events, and patient satisfaction. It lists one analysis. The results for the secondary outcomes and any adjustment for multiple outcomes are not reported in the registry record.

Multiplicity is a general statistical issue that arises when several hypotheses or outcomes are examined. If many tests are conducted, the chance of at least one apparently unusual result can increase unless the analysis plan accounts for the number and structure of tests. Whether adjustment is appropriate depends on the study objectives and prespecified plan. The registry record does not report a multiplicity strategy, so it is not possible to determine whether or how multiple outcomes were handled.

Missing-data information is also limited. The primary outcome description says pathology results from the index procedure were available within 14 days from the day the sample arrived at the pathological laboratory. It does not report the number of participants with unavailable pathology results, how missing outcomes were treated, or whether any sensitivity analysis was conducted. Missing-data methods and the reasons for missingness are not reported in the registry record.

The primary population is described as the Per Protocol Set, with inclusion based on eligibility and absence of serious protocol deviations that could affect efficacy. The description is truncated after mentioning two participants with serious deviations. The final number included in the analysis, exclusions, and handling of those participants are not reported in the registry record. Enrollment of 35 participants therefore should not be treated as confirmation that all 35 contributed to the primary analysis.

These omissions limit assessment of how completely the reported population represents enrolled participants and whether the analysis followed a prespecified plan. The registry record does not report an intention-to-treat population or a detailed missing-data analysis.

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 0% reporting threshold.

Most frequent non-serious adverse event terms

The safety figures list 35 participants at risk for serious adverse events, with 0 affected. Deaths are listed as 0. For other adverse events, 35 participants were at risk and 10 were affected. These are participant counts, not rates calculated.

The distinction between serious and other adverse events is important: the figures report no serious adverse events in the listed group, while other adverse events were reported in 10 participants. The registry record does not provide the specific event terms, timing, duration, severity details for the other events, or whether events were judged related to the device or procedure. The serious-event terms list is empty.

These counts describe the reported safety observations for the study group; they do not establish the absence of all risk. A safety summary is interpreted in the context of how events were defined, collected, and followed, and those details are not reported in the registry record. The study’s single-group design also does not allow direct comparison of event counts against a control group.

The listed number at risk gives the group size for these safety figures. It should not be assumed to be the same as the primary endpoint analysis population, whose denominator is not reported in the registry record.

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

The record establishes that a completed post-market study enrolled 35 participants and evaluated Breast Cancer Locator-guided breast-conserving surgery in a single group. It identifies positive margin rate as the primary outcome and provides a timeframe tied to pathology results from the index procedure. It also lists several secondary outcomes and safety counts.

The primary outcome result itself is not reported in the registry record. There is no positive-margin count or proportion, no reported primary analysis denominator, and no uncertainty interval. As a result, the available information does not show the observed positive margin rate or how precisely it was estimated. The study objective of evaluating performance in reducing positive margins should not be read as evidence that a reduction was demonstrated.

The design also limits what can be concluded even if a single-group outcome estimate were available. Without a concurrent comparator, the study does not directly measure a difference against another localization or surgical approach. A descriptive result in the treated group would not establish the outcome that would have occurred under a different approach.

The reported safety figures are limited to counts: 0 serious adverse events among 35 participants at risk, 0 deaths, and 10 participants with other adverse events among 35 at risk. The record does not report event details or comparative safety results. These counts should be read as the registry’s reported observations, not as proof that no other risks exist.

The record does not report results for the listed secondary outcomes, detailed statistical methods, missing-data handling, or a multiplicity strategy. It also does not fully state the primary analysis population because the Per Protocol Set description is incomplete. These gaps prevent a fuller appraisal of outcome magnitude, precision, and robustness.

Overall, the registry describes the study question, design, enrollment, and a limited set of safety counts, but does not report the primary efficacy result. No conclusion about the magnitude or comparative effect of the device can be drawn from the information reported.

14. Why This Trial Matters Statistically

This study is statistically notable because it evaluates a device in a post-market, single-group setting while identifying a clinically interpretable primary endpoint: positive margin rate after partial mastectomy. The endpoint is a participant-level binary outcome, and its meaning depends on a clear definition, an analysis denominator, and a transparent estimate of uncertainty.

The study record illustrates why design and result reporting must be considered together. A single-group study can describe outcomes among people who received the device, but it does not provide a direct randomized comparison. Even when enrollment and study completion are documented, an absent primary outcome result means that readers cannot judge the observed margin outcome or its precision.

Population definitions also matter. The endpoint description refers to a Per Protocol Set and gives criteria for inclusion, but the account is incomplete after mentioning two participants with serious deviations. The number enrolled is reported as 35, but the primary analysis denominator is not. In general, differences between enrollment and analysis populations can affect how readers interpret estimates and generalize results.

The registry also lists several secondary outcomes, but does not report their results or describe how multiple outcomes were handled. This underscores the importance of prespecified analysis plans and complete outcome reporting: a list of endpoints indicates what was intended for assessment, not what the observed findings were.

Finally, the safety counts are informative only within their reporting limits. They record no serious adverse events and 10 participants with other adverse events, but do not give event details or a comparison group. Statistical interpretation is therefore not just about a number; it also depends on the design, denominator, outcome definitions, and completeness of reporting.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The most important limitation for interpreting efficacy is that the primary positive margin result is not reported in the registry record. Without the count, denominator, or uncertainty interval, readers cannot assess the observed outcome or its precision. The primary population description is incomplete, so the number analyzed is also unclear.

The single-group design has no concurrent comparator. It can describe outcomes among participants who received the Breast Cancer Locator, but cannot estimate a direct between-group difference or separate the device’s contribution from other factors in care. Allocation is listed as NA, and masking is listed as NONE.

The record describes participants with non-palpable breast cancer in Europe and identifies a post-market, multicenter investigation. It does not report enough detail to assess the participating sites, participant characteristics, eligibility criteria in full, or how representative the study group was of other settings. Broader applicability therefore cannot be judged from the registry record.

The Per Protocol Set description is truncated after a reference to two participants with serious deviations. The record does not state the final analysis denominator, the handling of those participants, or whether other participants were excluded from the primary analysis. It also does not report missing pathology results or how missing data were handled.

The registry lists secondary outcomes but does not report their results or a multiplicity approach. Detailed statistical methods, a full statistical analysis plan, and a sample-size justification are not reported in the registry record. The listed planning assumptions are not evidence of the study’s design or of observed power. Safety reporting gives counts but not specific event terms, timing, or attribution, limiting interpretation of the adverse-event findings.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: CairnSurgical Breast Cancer Locator (BCL) Post-Market Study — NCT06461663.
• Registry record last updated 2026-05-27; status last verified 2026-03.
• Results first posted 2026-05-27.
• 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

The registry record identifies NCT06461663 as the CairnSurgical Breast Cancer Locator Post-Market Study. It describes a completed interventional, multicenter, single-group study of Breast Cancer Locator-guided breast-conserving surgery for participants with non-palpable breast cancer in Europe. The record lists 35 participants enrolled, a start date of 2022-06-22, and a primary completion date of 2024-04-19.

Positive margin rate is the primary outcome, with pathology results tied to the index procedure and a timeframe of within 14 days from the day the sample arrived at the pathological laboratory. The primary outcome result and final analysis denominator are not reported in the registry record. Secondary outcomes include specimen volume, surgeon’s perception, adverse events, and patient satisfaction; their results are also not reported.

Safety figures list 0 serious adverse events among 35 participants at risk, 10 participants with other adverse events among 35 at risk, and 0 deaths. The record lists one analysis but does not report detailed statistical methods, multiplicity handling, or missing-data methods.