Paclitaxel & Cyclophosphamide With or Without Trastuzumab Before Surgery in Treating Previously Untreated Breast Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Paclitaxel & Cyclophosphamide With or Without Trastuzumab Before Surgery in Treating Previously Untreated Breast Cancer (NCT01750073), a na phase 2 study. The primary outcome is Overall Incidence of Toxicities, Graded According to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) Version 4.0.

2. Clinical Question

The clinical rationale recorded for neoadjuvant treatment is that chemotherapy, with or without trastuzumab, may reduce tumor size before surgery. The registry describes this as a study of side effects and how well the treatment approach works, but the listed primary endpoint is toxicity incidence, not tumor response or survival. Clinical complete response, failure-free survival, overall survival, and gene-expression signatures related to pathologic complete response are listed as secondary outcomes.

The central question that can be addressed from the posted results is therefore limited: what safety counts were recorded for the treatment group, and how should those counts be interpreted without a randomized comparator or reported primary-outcome results? The record does not report a result for the primary endpoint broken down by HER2 status. It also does not report comparative estimates for the treatment strategies named in the title. The clinical question is broader than the statistical evidence available in this record.

3. Trial Design

This is a phase II study sponsored by the University of Nebraska. The registry records a single-group model, no masking, and allocation marked as not applicable. Enrollment is 92. The study began on 2012-12-07, had primary completion on 2022-05-01, and is listed as completed. These registry entries describe the registry entry; they do not establish that all enrolled participants contributed to every outcome.

The title refers to paclitaxel and cyclophosphamide with or without trastuzumab before surgery. However, the record describes one treatment group, “Treatment (chemotherapy, surgery, post-operative therapy),” and points to a detailed description that is not reported in the registry record. The intervention list includes cyclophosphamide, doxorubicin hydrochloride, paclitaxel, trastuzumab, surgery, radiation therapy, and laboratory biomarker analysis. The list alone does not specify which participants received each intervention, the sequence or duration of treatment, or how treatment was selected.

Because allocation is not randomized and the model is single-group, the record does not support treating the named “with” and “without” approaches as randomized arms. Differences between people who may have received different therapies could reflect their clinical characteristics or other treatment decisions, as well as the therapies themselves. The registry record does not report a prespecified comparative analysis addressing such differences.

The primary outcome is a count of participants with at least one adverse event in HER2-positive and HER2-negative subsets. Its timeframe is up to 30 days after completion of study treatment, with a maximum of 114 days. The registry lists seven outcome measures but no analyses. It does not report a sample-size justification, interim analyses, or a detailed statistical plan. Those omissions limit assessment of how the study was designed to estimate its outcomes and how the recorded results were intended to be analyzed.

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: 99 subjects were enrolled but 7 were screen fails (after signing consent) so only 92 started.

Overall Study

Analysis population for the primary outcome, as defined in the registry: All subjects who received at least one cycle of treatment and experienced an adverse event.

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 Overall Incidence of Toxicities, Graded According to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) Version 4.0, measured over Up to 30 days after completion of study treatment, maximum of 114 days.

The primary endpoint counts participants who experienced at least one adverse event, with events graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0. The endpoint is defined for HER2-positive and HER2-negative subsets and is expressed as a count of participants, rather than as a continuous measurement. Its stated population is subjects who received at least one cycle of treatment and experienced an adverse event. The timeframe is up to 30 days after completion of study treatment, with a maximum of 114 days.

Counting participants with at least one event is a way to summarize how many people experienced toxicity during the defined period. It differs from counting every event: a participant with multiple events still contributes as a participant who had an event. Such a measure can be useful for an overall safety summary, while giving limited detail about event frequency, duration, severity, or recurrence unless those are separately reported.

The endpoint definition specifies grading criteria, but the registry record does not report the primary endpoint counts by HER2 status or an estimate comparing those subsets. The broader serious and other adverse-event figures recorded elsewhere are not a substitute for the defined primary endpoint, since the endpoint concerns at least one adverse event and specifies HER2 subgroups and a particular follow-up period. The record also does not report how missing follow-up or incomplete event ascertainment was handled.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

For a binary endpoint, each participant is classified according to whether the event of interest occurred. Here, the primary outcome is defined as a count of participants experiencing at least one adverse event, with event grading based on CTCAE version 4.0. General statistical interpretation of a binary outcome depends on knowing both the number with an event and the denominator in the relevant analysis population. A count alone does not identify an event probability; a proportion can be estimated only when the corresponding denominator and inclusion rules are clear.

The registry states that the primary endpoint concerns HER2-positive and HER2-negative subsets, but does not report the subset-specific counts. It also describes the endpoint population as subjects who received at least one treatment cycle and experienced an adverse event. That wording does not fully explain how participants without an event, or participants with incomplete follow-up, are represented in the denominator. The registry record does not report a more detailed analysis-population definition or handling of missing data.

What does a single-group design allow?

A single-group design can describe outcomes observed among participants receiving the study treatment approach. Without a concurrent randomized comparator, however, it cannot separate treatment effects from other explanations for observed outcomes. General examples include differences in participant characteristics, clinical decisions, background care, or the natural course of disease. These are general design considerations, not claims about what occurred in this study. The registry record does not report a randomized comparison, and the title’s “with or without trastuzumab” wording does not change the listed single-group model.

For a treatment comparison, random allocation can help balance measured and unmeasured characteristics across groups on average. When allocation is not randomized, comparative analyses may require adjustment for relevant differences, but such adjustment cannot guarantee removal of confounding. The registry record does not report a comparative analysis or an adjustment strategy. Therefore no causal estimate comparing trastuzumab use with non-use can be drawn from the posted results.

How should uncertainty be assessed?

In general, an estimate is more informative when accompanied by an interval that communicates statistical uncertainty. Confidence intervals depend on the observed data and the analysis method. For a binary outcome, the interval’s interpretation also depends on the denominator and the method used to estimate it. No interval or analysis method for the primary endpoint is reported in the registry record. It is therefore not possible to assess the precision of a HER2-subgroup estimate from the record.

General hypothesis tests require a specified null hypothesis, a test statistic, and an analysis plan. A p-value is not a measure of the size or importance of an effect, and a nonsignificant result would not, by itself, demonstrate equivalence. No primary-outcome test or p-value is reported. The record also does not report a prespecified threshold for a clinically meaningful difference or an equivalence margin.

What can event counts conceal?

A participant-level “at least one event” endpoint treats a participant with one event and a participant with multiple events alike for that particular count. Event-level summaries can answer different questions, such as how often events occurred or which categories were recorded. Those summaries require clear definitions for severity, recurrence, attribution, and follow-up. The serious-event terms listed in the registry do not provide all of those details. In general, safety summaries may also be affected by how long participants were observed and whether event ascertainment was complete. The registry specifies a primary-outcome timeframe, but does not report the detailed follow-up completeness or missing-data methods.

The record includes planning-assumption language describing illustrations based on an observed effect, equal allocation, a two-sided significance level of 0.05, and a normal approximation. It also distinguishes illustrations for time-to-event outcomes from those for other outcomes. These assumptions describe planning illustrations, not observed power, and the record does not report the numerical illustration results. Since no observed primary-endpoint analysis is reported, those assumptions should not be treated as evidence that the study was powered for a particular endpoint or comparison. The registry record does not report the trial’s own sample-size justification.

More broadly, statistical interpretation depends on a prespecified analysis population, endpoint definition, follow-up rules, missing-data approach, and methods for any subgroup or multiple-outcome analyses. The registry lists several secondary outcomes but does not report the analysis methods, multiplicity strategy, or results for those outcomes. These omissions constrain reproducibility and make it difficult to judge whether the posted descriptive counts address the original analysis plan.

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("Her-2 Negative", "Her-2 Positive")
n      <- c(73, 19)
events <- c(73, 19)
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  Her-2 Negative  73  73  100.0  95.1  100.0  95.0  100.0  95.1  100.0
ARM  Her-2 Positive  19  19  100.0  82.4  100.0  83.2  100.0  83.2  99.9

11. Multiplicity, Missing Data and Analysis Populations

The registry lists seven outcome measures, including the primary toxicity outcome and secondary outcomes for clinical complete response, failure-free survival, overall survival, and gene-expression signatures associated with clinical response measured by pathologic complete response. It does not report analyses for these outcomes. The record also does not report a multiplicity plan describing whether or how statistical error across multiple outcomes or subgroup comparisons was controlled.

In general, testing multiple hypotheses can increase the chance of obtaining at least one apparently notable result by chance. Prespecified prioritization, adjustment procedures, or a clear distinction between confirmatory and exploratory analyses can help readers interpret a set of results. None of those methods is described in the registry record. Since no outcome analyses are listed, there are no reported tests from which to assess multiplicity in practice.

The primary outcome is defined for HER2-positive and HER2-negative subsets, but the record does not give their event counts or analysis denominators. It does not report whether participants were analyzed according to treatment received, whether all enrolled participants were included, or how participants who did not complete treatment or follow-up were handled. The stated primary-endpoint population refers to people who received at least one cycle and experienced an adverse event; further analysis-population details are not reported in the registry record.

In general, missing outcome data can affect both the estimate and its uncertainty, especially when missingness is related to a participant’s health or treatment experience. Appropriate handling depends on the amount and pattern of missingness and on assumptions about why data are missing. The registry record does not report missing-data counts, reasons for missingness, or an imputation or sensitivity-analysis approach. Accordingly, the completeness and potential impact of missing safety or efficacy information cannot be evaluated from the posted 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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: febrile neutropenia (5.4%), anemia (3.3%), infections and infestations (3.3%), sepsis (3.3%), dehydration (2.2%).

The registry lists 92 participants at risk for serious adverse events and 16 affected. It lists 92 at risk for other adverse events and 92 affected, and records 2 deaths. These are counts attached to the treatment group in the registry. They should be kept distinct: “serious” and “other” adverse events are separate categories in the posted summary, and the figures do not describe the same endpoint definition as the primary outcome unless the registry explicitly says so.

Listed serious adverse-event terms and their recorded percentages are febrile neutropenia, 5.4%; anemia, 3.3%; infections and infestations, 3.3%; sepsis, 3.3%; dehydration, 2.2%; and fever, 2.2%. The record does not report the term-specific denominators or clarify whether a participant could be counted under multiple terms. These percentages should not be summed to estimate the proportion of participants with any serious event.

In general, an adverse event occurring during a study is not automatically established as caused by the treatment. Attribution requires clinical assessment and a clear reporting definition. The registry record does not report the attribution of the listed events or deaths. Nor does it provide a comparative safety estimate from a randomized control group. The figures describe what is recorded, not a causal treatment effect or a comparison against background risk.

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

The record establishes that a phase II, single-group study enrolled 92 participants and is listed as completed. It describes a neoadjuvant treatment approach involving chemotherapy with or without trastuzumab and identifies toxicity as the primary outcome. The posted safety information includes counts for serious and other adverse events, a death count, and selected serious-event terms with percentages. These registry entries are useful for understanding what the registry records about the study’s safety reporting.

The record does not report the primary toxicity count separately for HER2-positive and HER2-negative participants, even though those subsets are part of the endpoint definition. It does not report analyses for the listed secondary outcomes, including clinical complete response, failure-free survival, overall survival, or gene-expression signatures. Without those results, the record cannot answer how those outcomes changed or how precisely they were estimated.

The title’s mention of treatment with or without trastuzumab does not establish a randomized comparison. The listed model is single-group and allocation is not applicable. As a result, the posted counts do not show whether adding trastuzumab changed toxicity, response, or survival relative to a comparable group without trastuzumab. The registry record also does not provide a causal analysis that could support such a conclusion.

General statistical interpretation distinguishes observed outcomes from treatment effects. An observed event count is a description of participants in the study; a treatment effect requires a suitable comparison and analysis. Even with a comparison, uncertainty and possible bias need assessment. The available record does not report confidence intervals, hypothesis tests, or a detailed analysis plan for the primary endpoint. The results therefore have limited statistical resolution: the event counts can be stated, but the precision of subgroup estimates and the size of any treatment effect cannot be established.

Nothing in the available record establishes that the treatment works or does not work. It also does not support medical advice. It supports a narrower reading: the registry describes a completed, single-group study and posts safety counts, while leaving important endpoint analyses and comparative evidence unreported.

14. Why This Trial Matters Statistically

This record illustrates why the design label and the endpoint definition need to be read alongside a study title. A title that names treatment “with or without” a drug can sound comparative, but the registry records a single-group model and allocation as not applicable. That information determines what comparisons the posted data can support. Descriptive event counts remain useful, but they are not equivalent to randomized comparative evidence.

The primary endpoint also illustrates the importance of matching the reported result to the endpoint as defined. The endpoint concerns participants with at least one adverse event in HER2-positive and HER2-negative subsets, during a specified treatment-related period. The available safety summary gives broader serious and other event counts, but does not report the primary endpoint counts by HER2 status. Readers therefore need to distinguish a safety summary from a complete report of the prespecified primary outcome.

More generally, statistical interpretation depends on transparency about denominators, analysis populations, uncertainty, missing data, and multiplicity. Those details determine how much confidence to place in a count or estimate and whether results can be reproduced. Here, the registry lists outcomes but no analyses and does not report several of those methodological details. The resulting limits are not a statistical verdict on the study’s quality; they define what can be inferred from this record.

The case is also a reminder that planning calculations and observed evidence answer different questions. Planning illustrations describe assumptions for a hypothetical design; they are not observed power and do not replace outcome estimates. The registry record does not report the numerical planning illustrations or the study’s own sample-size justification. Keeping these categories separate prevents a design assumption from being mistaken for a result.

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 main limitation for interpretation is the mismatch between the title’s apparent treatment contrast and the recorded single-group design. Allocation is not applicable, and no randomized comparator is described. The posted counts therefore cannot establish comparative effects of treatment with versus without trastuzumab.

The primary outcome is defined by HER2 subgroup, but subgroup counts and denominators are not reported. The registry lists 92 participants at risk for serious adverse events and 16 affected, and 92 at risk for other adverse events and 92 affected, but those summary figures do not provide the primary endpoint result by HER2 status. The record does not report confidence intervals, p-values, or other uncertainty estimates for that endpoint.

The registry does not provide a detailed treatment description, despite the arm description directing readers to one. It lists several interventions but does not clarify the treatment sequence, which participants received each intervention, or how treatment choices were made. It also does not report event attribution, term-specific denominators, or whether participants could contribute to multiple serious-event categories.

Further limitations arise from unreported analysis details. The record does not report a sample-size justification, a full statistical plan, an interim-analysis plan, the handling of missing data, analysis-population rules, or a multiplicity strategy. Although seven outcome measures are listed, no analyses are reported. Follow-up completeness and the handling of participants who did not complete treatment are also not reported in the registry record. These omissions prevent a full assessment of precision, potential bias, and reproducibility.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Paclitaxel & Cyclophosphamide With or Without Trastuzumab Before Surgery in Treating Previously Untreated Breast Cancer — NCT01750073.
• Registry record last updated 2026-06-26; status last verified 2025-11.
• Results first posted 2023-12-20.
• 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

This is a completed phase II study sponsored by the University of Nebraska, with enrollment of 92 and a single-group model. The registry lists no masking and allocation as not applicable. The title describes neoadjuvant paclitaxel and cyclophosphamide with or without trastuzumab before surgery; the intervention list also includes doxorubicin hydrochloride, surgery, radiation therapy, and laboratory biomarker analysis. The detailed treatment description is not reported in the registry record.

The primary outcome counts participants experiencing at least one adverse event, graded using CTCAE version 4.0, in HER2-positive and HER2-negative subsets. The timeframe is up to 30 days after treatment completion, with a maximum of 114 days. The registry lists seven outcome measures and no analyses. Posted safety figures include 16 participants affected by serious adverse events among 92 at risk, 92 affected by other adverse events among 92 at risk, and 2 deaths. The record does not report primary endpoint results by HER2 status or comparative efficacy analyses.