Streamlined Localization Using SCOUT® at Biopsy (STREAMLoc ): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Streamlined Localization Using SCOUT® at Biopsy (STREAMLoc ) (NCT04815291), a na na study. The primary outcome is Number of Participants Invasive Visits.

2. Clinical Question

3. Trial Design

STREAMLoc is registered as a single-group device study of receiving SCOUT at biopsy. The registry lists allocation as NA and masking as none; it does not describe a randomized allocation or a masked comparison. The arm description is the same device procedure. Because there is no control arm, the record cannot support a direct comparison of outcomes between SCOUT and another localization approach.

The listed enrollment is 93. The study start is 2022-04-01 and the primary completion date is 2024-01-15. The current status is terminated. The reason for termination, whether enrollment or follow-up ended as planned, and whether all intended assessments were completed are not reported in the registry record. The listed dates and status alone do not explain the study’s conduct or establish why it stopped.

The sponsor is Merit Medical Systems, Inc. The brief summary describes an intended evaluation in Canadian public and US healthcare systems with fixed resources, including assessment of efficacy, safety, and clinician and patient acceptance. These are stated aims, not proof that each was evaluated or that corresponding results were posted. The registry lists secondary outcomes of participants with adverse events and performance. It records 3 outcome measures and 0 analyses, so the analysis details and results for those measures are not available in the record.

The design is important to interpretation. Without a comparator, outcomes in the device group are descriptive. They cannot by themselves separate the effect of the device procedure from other influences, such as clinical practice, patient characteristics, or the care pathway. The registry also does not report the eligibility criteria, recruitment methods, baseline characteristics, protocol deviations, or analysis population. Those omissions limit assessment of how broadly the recorded experience may apply.

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.

Population: Although 93 subjects were enrolled as the overall number of baseline participants, there was one participant that did not have available data.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Invasive Visits, measured over through study completion, an average of 6 months.

The primary outcome is titled “Number of Participants Invasive Visits.” The unit is participants, and the listed parameter is a count of participants. The description, however, refers to the number of visits to the breast centre for an invasive procedure between biopsy and surgery. The title and parameter emphasize participants, while the description emphasizes visits. The registry does not clarify whether the outcome counts participants with at least one such visit, the total visits, or another operational definition. This difference in wording matters because a participant count and a visit count represent distinct quantities.

The timeframe is through study completion, an average of 6 months. This outcome is relevant to the stated process-improvement aim because visits for invasive procedures reflect an element of the care pathway between biopsy and surgery. Recording this burden may help characterize the process being studied. However, the registry record does not report the primary endpoint value, a definition of which visits qualify, or an analysis of the outcome. It therefore does not show how often the endpoint occurred or how precisely it was estimated.

A clear endpoint definition is needed to interpret a count consistently. For example, a participant-level measure requires an explicit rule for classifying whether a participant experienced the event, while a visit-level measure requires a rule for counting repeat visits. This is general statistical context; the registry does not specify which rule was used. The endpoint’s stated purpose can be described, but its observed result cannot be reconstructed from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group design permit?

A single-group study describes outcomes among participants receiving the intervention. It can document what was observed in that group, provided the outcome definitions and results are reported. It does not include a concurrent comparison group in the record, so it cannot directly estimate a between-group contrast. In general, a comparison is useful because it helps distinguish outcomes associated with the intervention from outcomes that may also occur under other care. Here, allocation is NA and the record identifies the design as single-group; no like-for-like control comparison is available.

This limitation applies even when an outcome is a straightforward count. A count in the intervention group alone does not show whether a different process would have produced a lower, higher, or similar count. Differences from a historical expectation would also require a clearly defined, appropriate reference and methods for accounting for differences in populations and care. Such a reference analysis is not reported in the registry record.

How should the primary outcome be understood?

The primary outcome’s wording combines a participant-count title with a description of visits. In general, a binary participant outcome classifies each participant according to whether an event occurred, while a count outcome may count repeated events. The registry identifies the outcome type as binary and describes its meaning as participants with an event, but does not give the operational event rule. The distinction between counting participants and counting visits should therefore remain visible when reading the outcome description. The record does not report the observed primary result, so neither an event frequency nor a visit total can be stated.

Clear outcome definitions also matter for follow-up. The stated timeframe is through study completion, an average of 6 months. An average does not by itself describe each participant’s actual observation period, and the registry does not report individual follow-up, censoring rules, or how incomplete observation was handled. General statistical practice would require clarity about these issues before interpreting an event count as a rate or comparing counts across groups.

What do uncertainty measures add?

In general, a confidence interval describes the range of values compatible with an estimate under a specified statistical method and its assumptions. It conveys uncertainty that a point estimate alone cannot show. A p-value, when used, addresses compatibility of data with a specified null model; it is not a measure of effect size or clinical importance. Neither an estimate nor these inferential statistics for the primary outcome are reported in the registry record. It is therefore not possible to assess the magnitude or precision of that outcome from the registry information.

Counts can also be affected by variation in observation time and by repeat events. General methods should match the data structure: participant-level event status differs from repeated visit counts, and over-dispersion can matter when count variability exceeds what a simple count model assumes. These are general considerations, not descriptions of analyses used in this study. The registry lists 0 analyses and does not report a model, variance assumptions, adjustment factors, or a statistical analysis plan.

How should planning illustrations be read?

The registry’s stated sample-size assumptions describe planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The stated effect to detect is a fraction of the observed effect. For time-to-event displays, the assumption says the result is a total number of events; for other outcomes, it says participants per arm. The registry does not report the primary observed effect or its analysis, so the basis for an illustration tied to that effect cannot be checked against a posted primary result.

In general, a planning calculation estimates the sample size required under specified assumptions to detect a target effect with a chosen probability, such as 80% power. It is not a measure of the probability that the study’s findings are true. A sample-size illustration is not observed power, and it does not repair the absence of a reported endpoint result. Its relevance depends on the outcome definition, target effect, variability assumptions, allocation, analysis method, and planned comparison. The registry’s stated equal-allocation assumption between two arms is a planning assumption, not a description of the actual single-group design.

Planning for a fraction of an observed effect is also hypothetical. In general, smaller target effects require more information to distinguish from random variation, but the calculation depends on the model and assumptions. It should not be treated as a result of the study or as evidence that the effect occurred. Here, the primary endpoint estimate is not reported in the registry record, and 0 analyses are listed. Thus, the planning framework can be described, but its numeric implications cannot be interpreted as observed outcomes or as confirmation of a treatment effect.

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("Device")
n      <- c(85)
events <- c(5)
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  Device  85  5  5.9  1.9  13.2  2.5  13.0  2.6  13.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 3 outcome measures, including secondary outcomes concerning participants with adverse events and performance. It records 0 analyses. The primary outcome result and any secondary outcome analyses are not reported in the registry record. The record does not identify which outcomes were tested, whether any were designated as key secondary outcomes, or whether an ordering or hierarchy was used.

When a study examines multiple outcomes, general statistical reasoning recognizes that repeated testing can increase the chance of finding at least one apparently unusual result by chance. A prespecified hierarchy or multiplicity adjustment can address that concern, depending on the study aims and analysis plan. The registry does not report whether either approach was planned or used. There is no basis to infer an adjustment method from the outcome list alone.

Missing-data methods and analysis populations are also not reported in the registry record. It does not state whether all participants with available data were included, how incomplete follow-up was handled, or whether any participants were excluded from outcome analyses. The listed enrollment of 93 does not establish the denominator used for the primary outcome, and it should not be substituted for an unreported analysis denominator.

These gaps limit reproducibility and interpretation. Without outcome-level denominators, definitions of missingness, and analysis methods, readers cannot judge whether the posted event counts reflect complete follow-up or how sensitive results might be to missing observations. Because the primary analysis itself is not reported, no conclusion about statistical significance or robustness is supported by the registry record.

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 adverse-event listing reports 0 serious adverse events among 93 participants at risk in the Device group. It reports 1 other adverse event among 93 participants at risk and 0 deaths. These are registry counts, not a comparison with another group. The serious-event terms list is empty, and the record does not provide a description of the other event, its timing, severity details, or whether it was considered related to the device.

A count of 0 recorded serious events does not prove that the underlying risk is absent. In general, rare events may not be observed in a study group, and event ascertainment and follow-up affect what is recorded. No confidence interval or safety analysis is reported in the registry record, so the precision of the serious-event count cannot be assessed from the posted information.

Likewise, the single other event should be read as a descriptive count, not as evidence of causation. The record does not state an attribution assessment or provide enough detail to interpret the event clinically. The reported safety figures should therefore be kept within their scope: they describe recorded counts in the Device group and do not establish comparative safety or the absence of unrecorded events.

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

The registry establishes that STREAMLoc was recorded as a single-group device study in which participants received SCOUT at biopsy. It states a process-focused primary outcome concerning invasive procedures between biopsy and surgery and lists adverse events and performance among its secondary outcomes. It also records the study status as terminated and lists an enrollment of 93. These registry entries describe the study’s registration and its stated aims; they are not themselves evidence that the intended process improvements or patient-experience aims were achieved.

The primary outcome result is not reported in the registry record. As a result, the record does not establish how many participants experienced the specified event, how many invasive visits occurred, or how precisely either quantity was estimated. The outcome wording also leaves unresolved whether the intended measure is a participant count or a visit count. No primary analysis is listed, so neither a statistical test nor an adjusted estimate can be attributed to this record.

The adverse-event counts describe events recorded in the Device group. They do not establish a causal relationship, rule out unreported events, or allow a comparison with an alternative approach. The lack of a comparator is especially important: even a complete descriptive outcome for the group would not show what would have occurred under another care pathway.

The record does not explain why the study was terminated, how complete the follow-up was, or which analysis populations were used. It also does not report detailed methods for the outcomes or the handling of missing information. Those omissions make it difficult to evaluate completeness, precision, and reproducibility. General statistical concepts such as confidence intervals and sample-size planning can help explain what further information would be useful, but they cannot supply missing study results.

The justified interpretation is therefore limited. The record documents a study intention and a small set of descriptive safety figures, but it does not provide the primary result needed to evaluate the invasive-visit question. It neither establishes a benefit nor establishes a lack of benefit. Any stronger conclusion would require outcome results and analysis details not reported in the registry record.

14. Why This Trial Matters Statistically

This study raises a statistically important distinction between measuring a care process and evaluating a causal effect. The stated primary outcome concerns invasive visits between biopsy and surgery, a process-related quantity that may be useful for describing patient pathways and resource use. But an outcome can be relevant without being fully specified or reported. The registry’s title and description do not make clear whether the intended unit is participants experiencing an event or visits themselves. That ambiguity affects the interpretation of any count.

The design also matters. A single-group study can document experience among people receiving the device procedure, but without a comparator it cannot establish how that experience differs from another approach. This is not a flaw that can be resolved by statistical testing alone: the missing comparative information is a feature of the design. A descriptive count and a causal comparison answer different questions.

Reporting is central to statistical evaluation. The registry lists 0 analyses and does not report the primary endpoint result. Without an estimate, denominator, and measure of uncertainty, readers cannot evaluate the outcome’s magnitude or precision. The listed adverse-event counts are useful as descriptive information, but they do not substitute for an analysis of the stated primary process outcome.

The record’s stated sample-size framework is also a reminder that planning assumptions need to be distinguished from observed evidence. Illustrations tied to a target effect can inform future study planning, but they are not observed power and do not demonstrate that an effect occurred. This distinction is particularly important when the registry does not report the observed primary result on which the planning framework is said to be based.

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 interpretation of this registry record. The primary endpoint result is not reported, and the record lists 0 analyses. The central process question therefore remains unanswered by the posted outcome information. Although the outcome description refers to visits, the title and parameter indicate a participant count. The operational definition needed to resolve this difference is not reported in the registry record.

The single-group design has no like-for-like control comparison. Allocation is NA, and masking is listed as none. Consequently, even a complete outcome count would be descriptive rather than a direct estimate of a difference between approaches. The record does not provide baseline characteristics, eligibility criteria, or information about participant selection, so the representativeness of the listed enrollment cannot be assessed.

The study status is terminated, but the reason is not reported in the registry record. The record does not say whether follow-up was complete, whether the termination affected outcome collection, or how many participants contributed to each outcome. Missing-data handling, analysis populations, and protocol deviations are also not reported. These omissions constrain assessment of bias and completeness.

Safety information is limited to the recorded event counts. The serious adverse-event terms list is empty, and detail about the other event and attribution is not reported. There is no comparative safety analysis or uncertainty estimate. Finally, the registry states planning assumptions but does not report an observed primary effect or analysis that would allow the planning basis to be independently evaluated. These limitations mean that the record supports only a cautious, descriptive reading.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Streamlined Localization Using SCOUT® at Biopsy (STREAMLoc ) — NCT04815291.
• Registry record last updated 2024-05-21; status last verified 2024-05.
• Results first posted 2024-05-21.
• 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

STREAMLoc is registered as a single-group device study of receiving SCOUT at biopsy for people with breast cancer. The listed enrollment is 93; the study started on 2022-04-01, has a primary completion date of 2024-01-15, and is marked terminated. The reason for termination is not reported in the registry record.

The primary outcome concerns invasive procedures between biopsy and surgery, through study completion, an average of 6 months. Its result and analysis are not reported, and its wording does not fully resolve whether it counts participants or visits. The registry lists adverse events and performance as secondary outcomes, 3 outcome measures, and 0 analyses.

For the Device group, the record reports 0 serious adverse events among 93 at risk, 1 other adverse event among 93 at risk, and 0 deaths. These are descriptive counts without a comparator. The record does not provide the primary result needed to assess the stated process question.