Immediate Postmastectomy Breast Reconstruction (Strattice Breast): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Immediate Postmastectomy Breast Reconstruction (Strattice Breast) (NCT00619762), a registered phase not stated study. The primary outcome is Histology Sample Evaluations Assessing Incorporation of StratticeTM Reconstructive Tissue Matrix.

2. Clinical Question

The question is therefore descriptive: what histologic features were evaluated in tissue associated with LTM use, and what clinical and safety observations were recorded? The registry entry does not state a comparative efficacy question, a control intervention, or an allocation procedure. It also does not report a numerical result for the primary histology endpoint. The posted record can identify the assessment plan and some adverse-event counts, but those details alone do not establish a treatment effect.

3. Trial Design

This was a multicenter, prospective, open-label study of LTM in two-stage breast reconstruction immediately after mastectomy. The registry reports enrollment of 17 and lists the study as completed. The recorded start is 2007-10 and primary completion is 2009-10. These dates describe the registry timeline; they do not fill in details about recruitment or follow-up that are not reported in the registry record.

The intervention is identified as a device: LTM, a porcine-based surgical mesh. The planned reconstruction involved an expander followed by a permanent implant. The primary histology assessment was scheduled at expander/implant exchange, identified as Stage II. The record describes assessment of fibroblast infiltration, immune cell response, and revascularization in tissue samples. A secondary outcome is the severity of local inflammation at and around the surgical site.

“Prospective” indicates that outcomes were to be assessed forward from study entry, while “open-label” indicates that the study was not described as blinded. The registry does not report who knew the treatment assignment during assessment, whether histology reviewers were blinded, or how any subjective assessments were standardized beyond the scoring description. Although the study summary describes three planned analyses, the registry record lists no analysis records. The timing, populations, and methods for those planned analyses are not reported in the registry record.

No comparator or allocation method is stated. The treatment-arm label appearing with the safety information does not establish a randomized arm structure or a control group. Accordingly, the design information supports reading the clinical and histologic observations as descriptive, rather than as a controlled estimate of the difference between treatments.

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: This study was a prospective, multicenter, open-label study with no control arm. All enrolled women/breasts remained in the study through expander/implant exchange up through the Month 3 post-exchange visit.

Overall Study

Analysis population for the primary outcome, as defined in the registry: All implanted patients enrolled in the study were included in the 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 Histology Sample Evaluations Assessing Incorporation of StratticeTM Reconstructive Tissue Matrix, measured over At the time of expander/implant exchange (Stage II),.

The listed primary endpoint is “Histology Sample Evaluations Assessing Incorporation of StratticeTM Reconstructive Tissue Matrix.” It is expressed as a percentage of breasts and assessed at expander/implant exchange (Stage II). The description identifies three histology parameters: fibroblast infiltration, immune cell response, and revascularization. Samples were assessed for fibroblasts or cellularity, neovascularization, and immune cell response using a 4 pt scale. The scale distinguishes degrees of observed features, from none through increasing amounts or intensity, with parameter-specific descriptions.

The endpoint is used to characterize tissue incorporation at the surgical site. In general, histology can provide a structured description of tissue features that may not be captured by a broad clinical outcome alone. In this record, the scoring descriptions explain what reviewers were to look for and how tissue appearance could be evaluated. The method also describes reviewing high-power fields and handling samples with non-uniform appearance, as well as assessing overall acellularity and expressing it as a percentage.

The registry record does not report the observed score distributions, the percentage of breasts with particular findings, or a summary estimate for the primary endpoint. Consequently, the endpoint description explains what was measured, not what the study found. The registry also does not report details such as the number of samples successfully assessed or the extent of missing histology data.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation depends on distinguishing the outcome definition, the analysis actually reported, and the conclusions that can be drawn from it. The registry describes a histology endpoint and safety counts, but does not report numerical results for the primary endpoint. A detailed measurement protocol is not a substitute for outcome data: it explains how observations were intended to be classified, not the distribution of those observations.

What does a confidence interval communicate?

In general, a confidence interval expresses uncertainty around an estimated quantity. Its width reflects how precisely that quantity has been estimated under the analysis assumptions. A narrow interval indicates more precision than a wide interval, but neither width nor location can be evaluated without the estimate and interval itself. The registry record does not report a confidence interval for the primary histology endpoint. It therefore does not permit an assessment of the statistical precision of an estimated histology result.

A confidence interval also does not automatically answer whether a finding is clinically important. That requires an outcome that is meaningful for the research question and an interpretation grounded in the study design. Here, no comparative estimate is reported, and no comparator is specified. General explanations about intervals cannot turn the histology description into evidence of a difference between treatments.

Why does the outcome’s scale matter?

The record describes histology ratings on a 4 pt scale, with specific descriptions for fibroblast infiltration, revascularization, and immune cell response. These are ordered categories: the descriptions indicate a progression in the amount or intensity of a feature. Such ratings can be reported as category frequencies or summarized using an appropriate method, but the choice affects interpretation. Category counts preserve the distinctions in the scale; a single summary can conceal how observations are distributed across categories. The record says that the parameters were expressed as frequency distributions, but the distributions themselves are not reported in the registry record.

The endpoint is also described as a percentage of breasts, and the protocol includes assessment of overall acellularity expressed as a percentage. These percentage-based descriptions require a clear denominator and a definition of what counts as an evaluable sample. The registry does not report the resulting values or the number of samples contributing to each assessment. No rate or percentage should be inferred from the study enrollment or from the safety counts.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variability in count data exceeds what a statistical model assumes. If a count model underestimates variability, uncertainty can appear smaller than it is, and inferential results may be too optimistic. Analysts can consider models or variance adjustments that accommodate extra variability, but the suitable approach depends on the outcome and design. The registry record does not report a count-data model, an over-dispersion assessment, or any analysis method for the primary outcome. This general issue should not be taken to mean that over-dispersion occurred in this study.

The histology ratings are not reported as count outcomes, and the registry does not provide the underlying observations needed to assess their variability. The general concept is relevant when analysts work with clustered or variable counts, but it cannot be used to reconstruct unreported analyses. Likewise, the record does not say whether assessments from multiple fields or samples were modeled as dependent observations.

What do the planning illustrations mean?

In general, a sample-size illustration asks how many participants per arm might be needed to detect an assumed effect under specified statistical assumptions. The illustrations associated with the posted results are planning illustrations based on the observed effect, not the trial’s original design. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect defined as a stated fraction of the observed effect. For time-to-event outcomes, such calculations concern the total number of events; other illustrations concern participants per arm.

These calculations are conditional on their assumptions. They do not describe the number enrolled in this study, prove that the original study was adequately powered, or estimate the probability that the study detected an effect. They are not observed power. The registry does not state that the study used these assumptions when it was designed, and it does not report a sample-size justification. Since the primary endpoint results are not reported in the registry record, the observed-effect basis for an illustration cannot be checked against the histology outcome from this record.

More broadly, a planning calculation cannot repair the absence of an analysis plan or outcome estimate. Interpretation still depends on the design, the definition of the endpoint, the number and quality of observations, missing data, and the uncertainty around results. Several of those details are not reported in the registry record. The statistical methods description should therefore be read as general guidance for understanding the kinds of analyses that may be used, not as confirmation of what the investigators did.

10. Multiplicity, Missing Data and Analysis Populations

The primary endpoint includes three histology parameters: fibroblast infiltration, immune cell response, and revascularization. The study summary also describes three planned analyses, and the registry lists 2 outcome measures, including the secondary outcome of local inflammation severity. The record does not explain how these outcomes and analyses were organized into a testing strategy. It does not report whether one measure was designated as the sole basis for a primary inference, whether multiple comparisons were adjusted, or how any analysis-specific hypotheses were handled. Multiplicity procedures are therefore not reported in the registry record.

In general, when researchers assess several outcomes or conduct several tests, the chance of obtaining at least one apparently notable result can increase if each test is interpreted separately. A prespecified strategy can help distinguish primary from exploratory findings and can address the consequences of multiple testing. That general concern cannot establish that any particular error occurred in this study. The registry record does not provide enough analysis detail to determine how multiplicity was addressed.

The primary-outcome population is described as all implanted patients enrolled in the study. The record does not report the number with usable histology samples, the handling of unevaluable tissue, or the treatment of missing observations. It does not state whether the safety counts use the same population as the histology analysis. Missing-data methods, exclusions, and reasons for unavailable outcomes are not reported in the registry record.

Although the summary describes planned analyses, the registry lists no analysis records. This limits assessment of which analyses were prespecified, which populations were used, and whether reported outcomes followed an analysis plan. The record does not establish that analyses were absent in practice; it establishes only that analysis details are not reported in the registry record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pneumothorax (5.9%), infection (5.9%), post operative bleeding (5.9%), breast deformity (5.9%).

The registry reports serious adverse-event figures of 3 affected among 17 at risk in the treatment-arm category. For other adverse events, it reports 2 affected among 29 at risk. These counts are reported as separate categories, but the record does not explain their relationship or why their at-risk counts differ. They should not be combined or interpreted as a single denominator. The registry also lists pneumothorax, Infection, post operative bleeding, and Breast deformity as top serious terms, each reported at 5.9%.

The listed term percentages do not, by themselves, show how many events occurred, whether a person could contribute more than one event, or whether terms overlap. The registry does not provide definitions for the adverse-event categories, event-level timing, severity beyond the serious classification, or attribution to the device. The record does not state whether the counts reflect all enrolled patients or another safety population.

These figures describe what the registry reports; they do not establish comparative risk. No comparator or allocation method is stated, and the safety categories are not described as like-for-like control arms. The counts should not be used to infer that a treatment caused or prevented an event.

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

The record establishes that a prospective, multicenter, open-label study was conducted to assess LTM in two-stage immediate post-mastectomy breast reconstruction. It describes the planned histology assessments and provides safety counts and serious-event terms. It also identifies an intended assessment time at expander/implant exchange (Stage II). These details make the study question and some aspects of outcome measurement visible.

The record does not report the numerical results for the primary histology endpoint. It therefore does not show the frequency distribution of fibroblast infiltration, immune cell response, or revascularization scores, nor the values for overall acellularity. It also does not report a comparison with another treatment, a confidence interval for a primary estimate, or a statistical test of a treatment difference. Without those results, the record cannot establish the magnitude or precision of a histologic finding.

The safety counts and listed serious-event terms are descriptive registry entries. Because the comparator and allocation method are not stated, they do not establish whether the observed counts differ from what would have occurred under another treatment or under no exposure to LTM. The figures also do not answer every question about event timing, attribution, overlap, or the population contributing to the counts.

In general, a clinical study’s description of what it intended to measure is distinct from evidence about what it observed. A planned endpoint can be useful for understanding the research question, but interpretation requires reported outcomes and information about how analyses were conducted. This record gives some design and measurement details but leaves those results and analysis details unreported. It should not be read as proof for or against a treatment effect.

13. Why This Trial Matters Statistically

This study is statistically notable because it combines a structured tissue-assessment plan with a registry record that does not report the primary endpoint results. The endpoint description is unusually specific about what histology reviewers were to assess: fibroblast infiltration, immune cell response, revascularization, and overall acellularity. That level of detail helps clarify the intended measurements, but it also highlights why outcome reporting matters. Without score distributions or percentages, readers cannot assess what the tissue evaluations found.

The study also illustrates the importance of separating descriptive evidence from comparative evidence. It is prospective and multicenter, but the registry does not state a comparator or allocation method. Design labels alone do not create a controlled contrast. The adverse-event counts can be described as registry-reported observations, but they cannot support a comparative risk estimate in the absence of a stated like-for-like comparison.

The discrepancy between the summary’s description of three planned analyses and the registry’s lack of analysis records is another important reporting issue. It leaves readers unable to identify the analysis populations, methods, and relationship between planned analyses and posted outcomes. This is not proof that analyses were not conducted; it is a limit on what can be evaluated from the registry record.

Finally, sample-size illustrations based on an observed effect have a planning role, not a role as observed power or proof of design adequacy. They depend on assumptions and on an effect estimate, while the registry does not report a sample-size justification or the primary histology results. The example reinforces a broader statistical principle: calculations are interpretable only in relation to the design, observed outcomes, and uncertainty that the record actually reports.

14. 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 consequential limitation of the registry record is that it does not report the primary histology outcome values. The listed endpoint and scoring descriptions do not reveal the observed distributions, and there is no reported estimate or confidence interval with which to judge precision. Thus, the central outcome cannot be statistically interpreted from this entry.

The study is not described as a randomized comparison, and allocation is not stated. No comparator is identified. As a result, the record does not support a direct estimate of how outcomes with LTM compare with outcomes under another intervention. The open-label design is reported, but the record does not state whether histology assessors were blinded or how observer agreement was evaluated.

Some details needed to understand the analysis population are also absent. The primary population is described as all implanted patients enrolled, but the number of evaluable samples, missing observations, and exclusions are not reported. The safety figures use different at-risk counts for serious and other adverse events, and the registry does not explain the difference. It also does not report event overlap, attribution, or timing.

The summary refers to three planned analyses, but the registry lists no analysis records. Statistical methods, multiplicity handling, and any sample-size justification are not reported in the registry record. The available information therefore supports a description of the study’s aims and some safety entries, not a complete appraisal of the primary endpoint or inferential analysis.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Immediate Postmastectomy Breast Reconstruction (Strattice Breast) — NCT00619762.
• Registry record last updated 2016-11-08; status last verified 2016-10.
• Results first posted 2013-05-15.
• 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.

18. Record Summary

NCT00619762 is a completed, prospective, multicenter, open-label study of LTM, a porcine-based surgical mesh, for two-stage immediate post-mastectomy breast reconstruction. The registry reports enrollment of 17 and lists Breast Cancer as the condition. The primary endpoint concerns histology evaluations at expander/implant exchange (Stage II), assessing fibroblast infiltration, immune cell response, and revascularization. Local inflammation severity is listed as a secondary outcome.

The primary histology results and analysis methods are not reported in the registry record. The entry includes safety counts and four top serious-event terms, each reported at 5.9%, but does not state a comparator or allocation method. The study summary describes three planned analyses, while the registry lists no analysis records. The available information is therefore descriptive and does not establish a comparative treatment effect.