Capecitabine as NeoAdjuvant Therapy in Locally Advanced Breast Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Capecitabine as NeoAdjuvant Therapy in Locally Advanced Breast Cancer (NCT00347438), a na phase 2 study. The primary outcome is Overall Clinical Response Rate (OCR).

2. Clinical Question

3. Trial Design

This was a Phase II study sponsored by the University of Chicago. The registry describes a single-group model, with no masking and no randomized allocation. Capecitabine was the intervention. The study was intended to evaluate the drug before surgery in women with newly diagnosed locally advanced breast cancer, including safety and clinical response.

The regimen description states that capecitabine was given at 1000mg/m2 twice daily for 2 weeks x 8 cycles, with a one-week pause in-between cycles. The primary response assessment was specified after the first three cycles, at an average of 9 weeks. The record does not describe a concurrent control arm, so the design does not support a direct randomized comparison with another treatment or with no treatment.

The registry lists enrollment of 18. It also states that the trial was terminated early because of slow accrual and that outcome measures were reported only for 16 patients who completed the first three cycles of chemotherapy. The record does not explain the outcome status of the other enrolled participants, so their absence from the reported primary-outcome group should not be assigned a reason.

The registry status is terminated. The start is listed as 2006-09 and primary completion as 2013-03. The record does not report the rationale for the planned enrollment, a statistical analysis plan, or whether any interim analyses were planned. Those details cannot be inferred from the phase, enrollment, or early termination alone.

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:

Analysis population for the primary outcome, as defined in the registry: This study was terminated early as a result of slow accrual. Thus, outcome measures were reported only for 16 patients who completed the first three cycles of capecitabine chemotherapy.

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 Clinical Response Rate (OCR), measured over After the first three cycles of therapy, an average of 9 weeks.

The primary endpoint was Overall Clinical Response Rate (OCR), expressed as a percentage of participants. It was defined as the proportion whose best response was either Complete Clinical Response (CCR) or Partial Clinical Response (PCR), assessed after the first three cycles of therapy, at an average of 9 weeks.

CCR was defined as complete disappearance of all measurable malignant disease, with no new malignant lesion, disease-related symptoms, or evidence of evaluable disease. PCR was defined as reduction by at least 50% of the sum of the products of the longest perpendicular diameters of all measurable lesions. These definitions make the endpoint a binary classification for each participant: a best response either met the complete-or-partial response definition or did not.

As a general statistical concept, a response proportion is a direct way to describe how often a specified clinical response was observed in a defined group over a specified assessment period. The endpoint can summarize tumor response without implying that the response was caused by treatment; that causal interpretation would require a suitable comparison and supporting design. The registry record does not report the OCR result, so neither the observed proportion nor its precision can be described.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of outcome was specified?

The primary endpoint was a binary response classification summarized as a percentage. For each participant, the definition asked whether the best response after the specified treatment period met the criteria for CCR or PCR. A proportion summarizes the number classified as responders relative to the number evaluated. The registry gives the assessment timing and the criteria, but does not report the responder count or the resulting proportion.

What does a confidence interval add?

As a general statistical concept, a confidence interval expresses uncertainty in an estimate arising from the fact that the observed participants are only one sample from a broader population of interest. A narrower interval indicates greater precision under the method's assumptions; a wider interval indicates less precision. An interval does not guarantee that an estimate is unbiased, and it does not make a single-group study equivalent to a controlled comparison. No confidence interval for OCR is reported in the registry record.

What can a single-group design estimate?

A single-group study can describe outcomes observed among participants who received the study intervention. It does not create a concurrent untreated or alternative-treatment group. As a general matter, without such a comparator, the observed response cannot separate a treatment effect from other explanations, including the course of disease, selection of participants, measurement choices, or other care. The registry describes no randomized allocation or masking, and no comparative treatment estimate is reported.

Why does the analysis population matter?

The registry states that outcomes were reported only for 16 patients who completed the first three cycles. This defines the group to which the reported outcome measures pertain, but the record does not explain how outcomes for other enrolled participants were handled. In general, restricting an analysis to people who completed a treatment period can affect interpretation if completion is related to prognosis, tolerability, or other factors. Whether that occurred in this study is not reported in the registry record. The record also does not say whether an intention-to-treat analysis, a per-protocol analysis, or another population definition was planned.

What analysis procedure was used?

The record identifies the primary endpoint as a percentage, but does not state the statistical method used to estimate it or to quantify its uncertainty. It lists 0 analyses. No hypothesis test, confidence-interval procedure, adjustment method, or model is described. Therefore, a particular method should not be attributed to the investigators. General methods for binary outcomes include estimating a response proportion and, when appropriate, calculating an interval around that estimate. The choice of method can matter, particularly when the evaluated group is small or the observed proportion is near an endpoint of its possible range.

What does early termination change?

Early termination because of slow accrual is an important feature of the record. In general, a smaller accumulated study population can leave estimates less precise than intended, but the record does not report the intended enrollment rationale or a planned precision target. It also does not state whether the primary analysis plan changed after termination. Early termination alone does not reveal the direction or size of any effect, and it is not evidence that a treatment did or did not produce response.

The registry record does not report a sample-size justification, interim-analysis plan, or statistical analysis plan. No analysis assumptions should be inferred from the Phase II designation. No trial-specific over-dispersion issue is identified: the primary endpoint is a participant-level response proportion, not a count rate or time-to-event outcome. In general, over-dispersion matters when observed variability exceeds what a specified model assumes; the record does not describe a model for which that issue can be assessed.

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("Capecitabine")
n      <- c(16)
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  Capecitabine  16  5  31.2  11.0  58.7  14.2  55.6  14.2  56.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 4 outcome measures, with Overall Clinical Response Rate identified as the primary endpoint. It lists 0 analyses. The record does not describe a multiplicity strategy, such as adjustment for testing more than one outcome, nor does it report multiple hypothesis tests. Without an analysis plan or test results, it is not possible to determine how the investigators intended to handle multiplicity. The existence of more than one outcome measure does not by itself show that multiple statistical tests were conducted.

The registry specifies that outcome measures were reported only for 16 participants who completed the first three cycles. It does not describe the missing outcome status of other enrolled participants, how missing measurements were handled, or whether any imputation was used. It also does not state whether the primary analysis was intended to include all enrolled participants or only those with an evaluable response assessment. The response estimate cannot be reconstructed from the record.

As a general statistical concept, missing outcomes can affect both the population represented by an analysis and the uncertainty around its estimate. The effect depends on why data are missing and on the analysis approach; neither is described. The record's statement that the trial ended early because of slow accrual does not establish why individual outcome data were unavailable. No assumptions about missingness or imputation should therefore be attributed to the study.

12. 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 non-serious adverse event terms

The adverse-event record lists the Capecitabine group with 16 participants at risk for serious adverse events and 0 affected. For other adverse events, it lists 16 participants at risk and 15 affected. These are counts of participants, not rates calculated. The registry does not provide further definitions or event-level details in this record, and no serious adverse-event terms are listed.

Deaths are not reported in the registry record. A recorded count of 0 participants affected by serious adverse events is a description of this recorded group; it does not establish that serious events are impossible or that all safety outcomes were fully captured. The group was limited to the participants listed as at risk, and the trial was terminated early because of slow accrual. These features limit how far the safety counts can be generalized. The counts should not be interpreted as a comparison with another treatment because no control group is described.

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

The registry record describes a Phase II, single-group study of capecitabine before surgery in women with newly diagnosed locally advanced breast cancer. It defines a primary clinical response endpoint assessed after the first three cycles and explains the criteria for complete and partial clinical response. It also records that the trial ended early because of slow accrual and that outcome measures were reported for 16 patients who completed those cycles.

However, the primary OCR result is not reported in the registry record. There is no response count, percentage, or confidence interval to interpret. The record therefore does not establish how often the defined response was observed or how precisely that frequency was estimated. The absence of a reported result is not evidence of no response, just as it is not evidence of a response.

The single-group design also limits what even a response proportion could mean. It would describe outcomes in the evaluated participants, not a comparative effect against another treatment. A causal claim would require a credible comparison and an analysis that supports that interpretation; neither is described in this record.

The safety information is similarly bounded: the record lists serious adverse events for the participants at risk, other adverse events, and no death count. These figures provide limited descriptive information, not a complete safety comparison. Overall, the registry supports a description of the study's question and design, but not a conclusion about the magnitude or certainty of clinical response or comparative benefit.

14. Why This Trial Matters Statistically

This trial illustrates a distinction that is central to reading clinical studies: an endpoint can be carefully defined even when its numerical result is unavailable. The registry describes OCR as the proportion with a best response of CCR or PCR and specifies the clinical criteria and assessment timing. That level of definition clarifies what the study intended to measure, but it cannot substitute for the missing result.

It also illustrates the difference between enrollment and the group with reported primary outcomes. Enrollment is listed as 18, while the registry says outcomes were reported only for the 16 patients who completed the first three cycles. The record does not explain the status of other participants or the handling of unavailable outcomes. Statistical interpretation depends on knowing which participants contribute to an estimate and how that group was formed.

The single-group design is another important teaching point. A response proportion can describe what happened among participants receiving capecitabine, but a concurrent comparator is needed for a direct treatment contrast. The record's Phase II label does not supply a statistical plan, a sample-size rationale, or a basis for causal conclusions; those details are not reported in the registry record.

Finally, early termination for slow accrual and absent endpoint results show why registry status and outcome reporting both matter. A transparent endpoint definition is useful, but readers also need the estimate, its uncertainty, and the analysis population to judge the evidence. Those elements are not reported, so statistical conclusions must remain limited.

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 trial-specific limitations constrain interpretation. The study was a single-group, unmasked Phase II study with no randomized comparator described in the registry. Consequently, there is no concurrent comparison for separating outcomes observed during capecitabine treatment from outcomes that might have occurred under another treatment or without it.

The trial was terminated early because of slow accrual. Enrollment is listed as 18, but the registry reports outcomes only for 16 patients who completed the first three cycles. It does not explain the outcome status of the other enrolled participants or report how any unavailable outcomes were handled. This makes the analysis population and the potential impact of incomplete outcome data difficult to assess.

The primary endpoint result itself is not reported in the registry record. There is no response count, proportion, or measure of precision to interpret. The record also does not report the statistical analysis plan, sample-size justification, interim-analysis plan, or multiplicity approach. These omissions prevent assessment of the intended analytical procedures and the rationale for the study's enrollment.

The record provides only limited safety counts: serious adverse events, other adverse events, and no reported death count. It does not provide event-level descriptions or a control-group comparison. These limitations are specific to the information recorded and should not be filled by assumptions about the protocol or unreported results.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Capecitabine as NeoAdjuvant Therapy in Locally Advanced Breast Cancer — NCT00347438.
• Registry record last updated 2015-12-14; status last verified 2015-11.
• Results first posted 2015-12-14.
• 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 Phase II study evaluated capecitabine as neoadjuvant therapy in women with newly diagnosed locally advanced breast cancer. It was a single-group, unmasked study sponsored by the University of Chicago. The described regimen was 1000mg/m2 twice daily for 2 weeks x 8 cycles, with a one-week pause in-between cycles.

The primary endpoint was overall clinical response after the first three cycles, at an average of 9 weeks. Enrollment was 18. The study was terminated early because of slow accrual, and the registry states that outcome measures were reported only for 16 patients who completed the first three cycles. The primary response result and statistical analyses are not reported in the registry record.

The safety record lists 0 serious adverse events among 16 participants at risk and 15 participants affected by other adverse events. Deaths are not reported in the registry record.