Standard Versus Continuous Capecitabine in Advanced Breast Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Standard Versus Continuous Capecitabine in Advanced Breast Cancer (NCT00418028), a randomized phase 2, phase 3 study. The primary outcome is Time to Progression.

2. Clinical Question

The trial record describes a randomized comparison in advanced breast cancer, with no masking. The schedules differ in both daily dose and whether treatment pauses between cycles. The brief summary says that the continuous schedule was intended to administer approximately the same cumulative capecitabine dose as the standard schedule. It also describes a hypothesis that continuous administration might reduce grade 2 or greater hand and foot syndrome, while the investigators assumed similar antitumor activity in both arms.

The posted primary outcome is time to progression, rather than hand and foot syndrome. The clinical question addressed by the primary result is therefore about the timing of progression or death due to progressive disease under the two schedules. The toxicity hypothesis and the assumption of similar antitumor activity provide context for the study, but the primary endpoint results do not by themselves answer every question about tolerability or activity. The registry identifies response and safety outcomes separately.

3. Trial Design

The registry describes a randomized, parallel-group trial with no masking. Its phase is listed as PHASE2 and PHASE3. The condition is metastatic breast cancer, and the intervention is capecitabine. Enrollment is recorded as 195. The trial status is completed; the registry lists a start in 2005-09 and primary completion in 2011-12.

Arm A, labeled Cint, received the standard intermittent schedule: capecitabine 1250 mg/m2 orally twice daily for 14 days in 3 week cycles, followed by a 7 day rest. Arm B, labeled Ccont, received 800 mg/m2 orally twice daily for 21 days in 3 week cycles without a rest period. Both descriptions state that treatment continued until disease progression or severe toxicity. Dose adjustments are mentioned, but the arm descriptions do not give a complete account of their implementation. Further dose-adjustment details are not reported in the registry record.

The primary endpoint is time to progression. Its analysis description says that 192 patients were considered, with 95 in Arm A and 97 in Arm B; 36 were censored, comprising 23 in Arm A and 13 in Arm B. The reported median estimates use the analysis counts shown for each arm, which differ from the counts considered in the primary analysis description. The reasons for these differences are not reported in the registry record.

The listed secondary outcomes are response rate, response duration, time to treatment failure, overall survival, clinical benefit, and progression-free survival. Numeric results are posted for response rate, response duration, and time to treatment failure. Numeric results for the other listed secondary outcomes are not reported in the registry record. The trial's original sample-size justification, planned interim analyses, and full statistical analysis plan are not reported in the registry record.

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

Analysis population for the primary outcome, as defined in the registry: A total of 192 patients (95 in Arm A and 97 in Arm B) were considered for this analysis but 36 were censored (23 in Arm A and 13 in Arm B). Patients censored are those that did not progress or die due to progressive disease during the study treatment.

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 Time to Progression, measured over After 1 year from the treatment start day..

Time to progression measures the interval from starting study treatment to progressive disease. The registry also counts death due to progressive disease as an event. It defines progression using RECIST v1.0, a set of criteria for assessing tumor response and progression. The stated timeframe is after 1 year from the treatment start day, while the endpoint description defines the event and time origin.

The registry reports the endpoint as a median with a 95% confidence interval. A median time-to-event estimate describes the point by which half of the analyzed group has experienced the event, subject to the time-to-event estimation method and the censoring information. It is not an average and does not describe each participant's individual course.

Time-to-event methods are useful when participants may have different lengths of observation or may leave follow-up without experiencing the event. Such participants can contribute information up to the last point at which their status is known; this is censoring. The primary analysis description says that patients who did not progress or die due to progressive disease during study treatment were censored. Censoring means the event time is not observed within the relevant follow-up, not that the event can be assumed never to occur.

This endpoint captures progression timing under the registry's definition. It does not directly measure every aspect of treatment experience, such as toxicity, response duration, or overall survival. Those outcomes are listed separately. The endpoint and its definition therefore set the scope of what the primary result can address.

7. Results Posted in the Registry

• Arm A (Cint) vs Arm B (Ccont): hazard ratio 1.30 (95% CI 0.90–1.70), reported p = 0.122 (as reported in the registry).

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Response Rate

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Arm B (Ccont): 33.3% (31/93) versus 34.9% (30/86) on control; risk difference -1.6 percentage points (95% CI -15.5 to 12.4), risk ratio 0.96 (0.64–1.44); unadjusted two-proportion z-test p = 0.827.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Arm B (Ccont) and the control. The interval gives the range of effects that remain compatible with the data.

Response Duration

• Endpoint type: Time to event: compared as a hazard ratio.
• Test: Hazard ratio as reported by the sponsor (Log Rank); it was not recalculated.
• Result:
  • Arm A (Cint) vs Arm B (Ccont): hazard ratio 1.18 (95% CI 0.67–2.07), reported p = 0.570 (as reported in the registry).
• Interpretation:
  • The 95% confidence interval includes no difference (a ratio of 1), so these data do not show a statistically significant difference between Arm A (Cint) vs Arm B (Ccont) and the control. The interval gives the range of effects that remain compatible with the data.

Time to Treatment Failure

• Endpoint type: Time to event: compared as a hazard ratio.
• Test: Hazard ratio as reported by the sponsor (Log Rank); it was not recalculated.
• Result:
  • Arm A (Cint) vs Arm B (Ccont): hazard ratio 1.12 (95% CI 0.83–1.50), reported p = 0.468 (as reported in the registry).
• Interpretation:
  • The 95% confidence interval includes no difference (a ratio of 1), so these data do not show a statistically significant difference between Arm A (Cint) vs Arm B (Ccont) and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes add context across response, duration, and treatment continuation, but they do not replace the primary time-to-progression result. The posted response-rate comparison is a categorical analysis. Response duration and time to treatment failure use time-to-event summaries. Across these outcomes, the point estimates do not form a consistent pattern that independently resolves the uncertainty in the primary comparison.

These outcomes measure different aspects of treatment. Response rate concerns whether a response was recorded; response duration concerns how long a response persisted before progression or death; and time to treatment failure includes several reasons for ending treatment. Each has a different event definition and, in the registry, a different analysis population. Their results should not be treated as interchangeable measures of one underlying effect.

The record lists overall survival, clinical benefit, and progression-free survival as secondary outcomes, but numeric results for these outcomes are not reported in the registry record. Their absence limits how fully the secondary outcome pattern can be assessed. The secondary outcomes therefore provide only a partial picture alongside the primary endpoint.

Unadjusted secondary results carry less weight when several outcomes are examined because each additional comparison creates more opportunity for an apparently notable finding to arise by chance. Whether the trial used a multiplicity adjustment, a hierarchy of outcomes, or another strategy to control interpretation is not reported in the registry record. The secondary findings should consequently be treated as supportive or exploratory rather than as independent confirmation of the primary result. They neither establish equivalence nor overturn the uncertainty reflected in the primary confidence interval.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Response Rate
• Response Duration
• Time to Treatment Failure
• Overall Survival
• Clinical Benefit
• Progression Free Survival

9. Statistical Interpretation

10. Statistical Methods Explained

What does a median time-to-event estimate describe?

A median time-to-event estimate is a summary of when events occur in a group. It differs from a simple average because it is based on the distribution of event times and can account for censoring. In this trial, the event is progression or death due to progressive disease, and time begins when study treatment starts. The median does not imply that every participant experienced an event at that time, and it does not show the range of individual experiences.

The registry gives a 95% confidence interval alongside each median. In general, a confidence interval describes the statistical uncertainty of an estimate under the method used. A narrower interval indicates greater precision, while a wider interval indicates less precision. It is not a range containing every participant's event time, and it does not guarantee that the true value falls inside the particular interval.

How should censoring be understood?

Time-to-event analyses can use information from people whose event has not been observed by the end of their available follow-up. Their observation is censored at the last relevant point rather than treated as if an event occurred then. The primary analysis description reports 36 censored patients, with 23 in Arm A and 13 in Arm B, and defines censoring as not progressing or dying due to progressive disease during study treatment.

Statistical interpretation relies on assumptions about censoring and the completeness of follow-up. The registry description does not report a detailed account of follow-up after treatment, reasons for censoring beyond its general definition, or methods for assessing how censoring may affect the comparison. These details matter because censoring that is related to prognosis can complicate interpretation.

What does the log-rank comparison do?

The registry reports a log-rank test and a hazard ratio for the primary comparison. In general, the log-rank test compares the observed pattern of event timing between groups over follow-up. A hazard ratio summarizes the relative event rate at a given time under the assumptions of the analysis. A hazard ratio is not a difference in median months, and it does not directly describe the proportion of participants who experienced an event.

The proportional hazards assumption is often relevant when interpreting a single hazard ratio: it treats the relative hazard as reasonably stable over time. Whether that assumption was checked, and how departures were handled, are not reported in the registry record. The reference coding for the reported comparison is also not explained in further detail. The reported estimate and interval should therefore be interpreted as registry results, not as a complete account of the model specification.

The log-rank p-value assesses how compatible the observed comparison is with a statistical null hypothesis under the test's assumptions. It does not measure the size or clinical importance of a difference, and it does not give the probability that the null hypothesis is true. The confidence interval and the endpoint estimates provide complementary information about magnitude and precision.

How do the secondary endpoint methods differ?

Response rate is reported as a participant count by arm, with a chi-squared comparison. In general, a chi-squared test evaluates whether categorical outcome patterns differ between groups. The registry's sponsor-reported p-value is 0.827. An unadjusted recalculation from the posted response counts gives p = 0.827. These values are close, and the record does not identify a discrepancy.

Response duration and time to treatment failure are reported as median time-to-event outcomes with 95% confidence intervals, and their comparisons use log-rank tests and hazard ratios. Response duration starts when a partial or complete response is reported and ends at progression or death, whichever happens first. Time to treatment failure runs from treatment start to treatment end for reasons listed in the registry, including death, progressive disease, adverse events, participant decision, or investigator criteria.

General statistical interpretation also depends on how analysis populations, missing information, and multiple outcomes were handled. The registry does not report a full protocol-level description of these methods. The outcome-specific analysis counts differ, and the reasons for those differences are not reported in the registry record. Results should be considered in the context of these limits rather than treated as a complete reconstruction of the trial analysis.

11. Confidence Intervals and Precision

The primary median estimates are 8.68 months in Arm A (Cint), with a 95% confidence interval from 6.55 to 11.05, and 6.84 months in Arm B (Ccont), with a 95% confidence interval from 6.02 to 8.06. The reported hazard ratio is 1.3, and its 95% confidence interval extends from 0.9 to 1.7. That interval includes 1, so the data are compatible with no relative difference as well as with relative differences in either direction under the reported comparison.

Confidence intervals express uncertainty in estimates, not variation among individual participants. The median intervals overlap, but overlap alone is not a formal test of the between-arm comparison. The reported hazard-ratio interval and log-rank p-value are the registry's direct comparative statistics. The p-value is 0.122. Taken together, these results do not provide a precise estimate that rules out a range of possible relative effects.

The secondary time-to-event estimates also have intervals of varying width. For response duration, the reported median is 10.07 months in Arm A, with a 95% confidence interval from 7.96 to 16.71, and 7.2 months in Arm B, with a 95% confidence interval from 4.11 to 12.7. Its hazard ratio is 1.18, with a 95% confidence interval from 0.67 to 2.07. For time to treatment failure, the medians are 5.41 months and 5.87 months, with intervals from 4.34 to 8.03 and from 3.55 to 7.14, respectively; the hazard ratio is 1.12, with a 95% confidence interval from 0.83 to 1.5. These comparisons also have intervals that include 1.

Intervals should be read in relation to the endpoint, analysis population, and method used. They do not establish that outcomes are equivalent, and they do not indicate whether an observed difference matters clinically. The registry does not report prespecified equivalence margins or a detailed account of interval construction beyond identifying the confidence level and analysis method.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning illustrations use the observed effect as a starting point and show estimates for detecting the full observed effect, 75% of the observed effect, and 50% of the observed effect. For the response-rate comparison, the displayed figures are participants per arm. For the time-to-event comparisons, the figures are total events, not participants per arm. Event counts and participant counts are different planning quantities: the number of participants needed to observe a target number of events depends on follow-up and event occurrence.

The assumptions listed for these illustrations are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is the stated fraction of the observed effect. The original trial's sample-size assumptions and justification are not reported in the registry record; these illustrations are separate planning calculations based on the observed results.

The 80% power column means the number of participants per arm, or total events for time-to-event outcomes, estimated to give an 80% chance of detecting the specified effect under the listed assumptions. The 90% power column gives the corresponding estimate for a 90% chance. These are planning targets conditional on the assumptions, not guarantees of a future study's results.

Smaller effects require more information to distinguish them from random variation. Accordingly, the planning estimates increase when the target is reduced from the full observed effect to 75% or 50% of it. This is not observed power: it is not a measure of how likely the completed trial was to detect its effect. The illustrations do not establish that a future trial will reproduce the observed effect, and they do not replace an independently justified design.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

d is the total number of events needed (Schoenfeld's formula) with 1:1 allocation and proportional hazards.

Worked calculation for this trial

1. Hazard ratio HR = 1.300, so ln(HR) = 0.2624.
2. d = 4 × (1.96 + 0.842)² / [ln(1.300)]² = 456.1, rounded up to 457 events in total for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
hr <- 1.3                              # observed hazard ratio
events_needed <- function(power, frac = 1) ceiling(round(4 * (z_a + qnorm(power))^2 / log(hr^frac)^2, 6))   # Schoenfeld, 1:1 allocation
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: events = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(events_needed(0.80, f), big.mark = ","), format(events_needed(0.90, f), big.mark = ",")))

# Simulation: given d total events under proportional hazards, events in the treatment arm are Binomial(d, hr / (1 + hr)).
# The score (log-rank type) statistic is (D1 - d / 2) / sqrt(d / 4).
set.seed(418028)
d    <- events_needed(0.80)
reps <- 20000
D1 <- rbinom(reps, d, hr / (1 + hr))
z  <- (D1 - d / 2) / sqrt(d / 4)
cat(sprintf("Simulated power with %s events: %.3f (%d replicates)\n", format(d, big.mark = ","), mean(abs(z) > z_a), reps))

Output from running the code

100% of observed effect: events = 457 (80% power), 611 (90% power)
 75% of observed effect: events = 811 (80% power), 1,086 (90% power)
 50% of observed effect: events = 1,825 (80% power), 2,443 (90% power)
Simulated power with 457 events: 0.795 (20000 replicates)

The simulation uses the fact that, with d events in total and proportional hazards, the number of events in the treatment arm is binomial. It is an approximation that conditions on the total number of events, and it should land close to the target power.

14. Analyses Reported by the Sponsor

The registry reports the sponsor's primary comparison as a log-rank hazard ratio of 1.3, with a 95% confidence interval from 0.9 to 1.7 and p = 0.122. The reported medians are 8.68 months in Arm A and 6.84 months in Arm B. The sponsor's comparison is the primary source for the trial's reported analysis.

For response rate, the sponsor reports a chi-squared p-value of 0.827. A simple unadjusted recalculation from the posted counts gives p = 0.827. The values are close, and the registry record does not identify a discrepancy. The recalculation is a check based on summary counts; it does not reproduce any analysis that may have used participant-level data or other adjustments.

For time-to-event outcomes, no alternative recalculated hazard ratios are presented. The reported estimates rely on the sponsor's analyses, including the log-rank comparisons. If a recalculation conflicted with a sponsor-reported analysis, the sponsor's own analysis would take precedence for describing the trial result. That precedence does not remove the need to consider the reported interval, analysis population, endpoint definition, or unreported analysis details.

The sponsor-reported p-values are not evidence by themselves that the schedules are equal or different. Estimates and intervals are more informative about magnitude and precision, while the test results address compatibility with a null hypothesis under the specified analysis. The record does not provide enough detail to independently reproduce the full time-to-event analyses.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists several secondary outcomes in addition to the primary time-to-progression endpoint. When multiple endpoints are tested, the chance of at least one seemingly unusual result can increase, even if the outcomes are not truly different between groups. General approaches to this issue include prespecifying a hierarchy, adjusting the testing threshold, or treating secondary analyses as exploratory. Which approach was used in this trial is not reported in the registry record.

The registry does not report a complete statistical analysis plan, the protocol's planned analysis populations, or whether any interim analyses were conducted. The original sample-size justification is also not reported in the registry record. These omissions prevent a full assessment of whether the analyses and interpretation followed prespecified plans or whether the trial was designed around the primary endpoint's eventual estimate.

The primary endpoint description reports 192 patients considered for analysis and notes 36 censored patients. Its arm-level median estimates have analysis counts of 72 and 84. These counts do not match the numbers considered in the endpoint description, and the reasons are not reported in the registry record. The secondary endpoints also use different analysis counts. The record does not explain the outcome-specific populations or whether missing observations were excluded, imputed, or otherwise handled.

Censoring is part of time-to-event analysis, but interpretation depends on how follow-up ended and whether censoring may relate to the outcome. The record gives a general definition of censoring for the primary endpoint, but detailed reasons, follow-up procedures, and sensitivity analyses are not reported in the registry record.

These reporting gaps do not invalidate the posted results, but they limit independent assessment of multiplicity, missing data, and analysis-population choices. The estimates and intervals can be described as reported; stronger claims about robustness or prespecification require information that the registry record does not provide.

16. 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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: diarrhea (6.3%), febrile neutropenia (2.1%), obstruction (1.1%), ventricular arrhythmia (1.1%), mucositis/stomatitis (1.1%).

The registry reports serious adverse events affecting 13 of 95 patients at risk in Arm A (Cint) and 4 of 97 at risk in Arm B (Ccont). It also reports other adverse events affecting 81 of 95 at risk in Arm A and 51 of 97 at risk in Arm B. These are arm-specific counts as recorded, not adjusted comparisons. The record does not provide a comparative statistical analysis of these safety counts.

The serious adverse event terms most often listed include diarrhea at 6.3%, febrile neutropenia at 2.1%, and obstruction, ventricular arrhythmia, mucositis/stomatitis, and neutrophils/granulocytes (ANC/AGC) at 1.1% each. These entries describe reported terms and percentages; they do not establish that the event was caused by treatment or that the schedules differ in safety.

The registry does not report deaths in the adverse-event group information. Definitions, event-specific exposure time, severity breakdowns beyond the serious-event classification, and details of attribution are not available in the record. Counts should therefore be read as descriptive safety reporting rather than as a complete comparative safety assessment. They should not be combined with the efficacy results to infer a treatment recommendation.

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

The primary result is an estimate of time to progression under two capecitabine schedules in the trial population. The reported medians and hazard ratio describe the observed comparison, while the confidence interval shows that the relative effect remains uncertain. The analysis does not demonstrate that the schedules are equivalent, and it does not establish a clear difference in time to progression.

The result also does not directly answer the trial brief's hypothesis about reducing hand and foot syndrome. That symptom appears in the study rationale, but the primary endpoint is time to progression. The safety information posted in the registry gives adverse-event counts and selected serious-event terms, yet it does not provide a complete analysis of the specific toxicity hypothesis. Likewise, the primary endpoint alone cannot settle questions about response, overall survival, quality of life, or other aspects of treatment experience.

A non-significant p-value is not proof of no effect. It indicates that the observed data are not sufficiently incompatible with a null comparison under the test to meet a conventional significance threshold. The confidence interval remains compatible with a range of effects. Without a reported equivalence or non-inferiority margin and its justification, the result cannot be read as evidence that clinically meaningful differences have been ruled out.

The registry's phase listing, randomization, and parallel design describe important features of the study, but they do not eliminate uncertainty from censoring, differences in analysis counts, or unreported analysis procedures. The findings are specific to the participants, schedules, endpoint definitions, and analyses described in the record. They should be interpreted as trial evidence with limits, not as a universal conclusion about capecitabine scheduling.

The result is most useful as a quantitative account of the observed time-to-progression comparison and its imprecision. It does not by itself establish which schedule should be used, whether either schedule is preferable for a particular patient, or whether the study's toxicity hypothesis was confirmed.

18. Why This Trial Matters Statistically

This trial illustrates why a treatment comparison should be read through both its endpoint estimates and their uncertainty. The median times give an interpretable summary within each arm, while the hazard ratio and confidence interval address the relative time-to-event comparison. Considering these measures together helps avoid treating a difference between point estimates as conclusive evidence of a treatment effect.

It also illustrates that a trial's clinical rationale and its primary endpoint may not be the same question. The brief describes a hypothesis about hand and foot syndrome and an assumption about antitumor activity, but the primary analysis is time to progression. A careful reading keeps those questions separate and avoids using an endpoint to answer a different outcome question.

The trial also highlights the importance of analysis populations and censoring in time-to-event studies. The registry gives counts considered for the primary analysis, counts censored, and different counts for the median estimates. Because the reasons for these differences are not reported, readers must recognize that the numerical summaries are attached to particular analysis populations rather than assuming a single denominator applies throughout.

Finally, the planning illustrations show how design requirements depend on the effect a future study aims to detect. Smaller target effects require more information under the listed assumptions. These estimates are not evidence about the power of the completed trial and are not substitutes for a prospective design justification. This distinction matters when translating observed results into plans for future research.

19. 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 registry record does not report the original sample-size justification, the complete statistical analysis plan, or the rationale for the trial's phase listing as both PHASE2 and PHASE3. It also does not report whether interim analyses occurred, how multiplicity was addressed, or whether the reported analyses followed prespecified outcome hierarchies. These omissions limit assessment of design and analytic decisions.

For the primary endpoint, the record says 192 patients were considered, reports 36 censored patients, and gives median-estimate analysis counts of 72 and 84. The reasons for the differences among these counts are not reported in the registry record. Detailed follow-up procedures, reasons for censoring, sensitivity analyses, and checks of time-to-event model assumptions are also not reported.

The arm descriptions mention dose adjustments but do not provide complete details. The registry therefore does not allow a full account of how dose changes, interruptions, or adherence may have affected exposure. The brief says the schedules were intended to deliver approximately the same cumulative dose, but the record does not provide a comparative measure of delivered dose.

The numeric secondary results are incomplete relative to the listed outcomes: results for overall survival, clinical benefit, and progression-free survival are not reported in the registry record. Safety information is descriptive, without a reported comparative analysis or sufficient details about event attribution and exposure time. These limitations constrain interpretation beyond the posted primary comparison and the specific secondary results available.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Standard Versus Continuous Capecitabine in Advanced Breast Cancer — NCT00418028.
• Registry record last updated 2019-02-22; status last verified 2019-02.
• Results first posted 2017-12-18.
• 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.

23. Record Summary

NCT00418028 is a completed randomized, parallel-group trial with no masking, comparing standard intermittent and continuous capecitabine in advanced breast cancer. The registry lists enrollment as 195 and the primary endpoint as time to progression.

The reported median time to progression was 8.68 months in Arm A and 6.84 months in Arm B. The reported hazard ratio was 1.3, with a 95% confidence interval from 0.9 to 1.7 and p = 0.122. The interval includes 1 and leaves uncertainty about the relative comparison.

Response rate, response duration, and time to treatment failure have posted numeric results; the other listed secondary outcomes do not. The registry's analysis-plan details, original sample-size justification, multiplicity approach, and reasons for differences in analysis counts are not reported in the registry record.