This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Tamoxifen Citrate or Letrozole With or Without Bevacizumab in Treating Women With Stage IIIB or Stage IV Breast Cancer (NCT00601900), a randomized phase 3 study. The primary outcome is Progression-free Survival.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00601900 |
| Phase | Phase 3 |
| Condition | Invasive Breast Carcinoma, Recurrent Breast Carcinoma, Stage III Breast Cancer AJCC v6 |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 394 |
| Arms in the primary outcome | 2 |
| Lead sponsor | National Cancer Institute (NCI) |
| Results posted | Yes |
2. Clinical Question
Population
Women with hormone receptor-positive advanced breast cancer, including stage IIIB or stage IV disease. The trial record describes a primary-endpoint analysis limited to participants who elected letrozole; 343 were evaluable for that analysis.
Intervention
Endocrine therapy with bevacizumab. Endocrine therapy was tamoxifen citrate or letrozole, selected by participants. For the letrozole primary-endpoint group, the reported comparison concerns letrozole alone versus letrozole plus bevacizumab.
Comparator
Endocrine therapy without bevacizumab. Participants received tamoxifen citrate or letrozole, according to their selected endocrine therapy.
Primary question
Among women choosing letrozole as first-line endocrine therapy, how did progression-free survival compare between letrozole plus bevacizumab and letrozole alone? Progression-free survival was the time from randomization to disease progression or death, whichever occurred first.
The registry record describes a randomized phase III comparison in women with advanced breast cancer. The overall trial enrolled 394 participants, but the primary endpoint was not analyzed across that full enrollment: the primary analysis was restricted to participants electing letrozole. Of 348 who elected letrozole, 5 did not receive treatment, leaving 343 evaluable participants, with 173 assigned to endocrine therapy plus bevacizumab and 170 assigned to endocrine therapy alone.
The intervention was not a single endocrine drug for all participants. The regimen included tamoxifen citrate or letrozole, and the primary question specifically concerns the letrozole subgroup. This distinction matters when interpreting the estimates: they describe the stated letrozole analysis population, not necessarily every participant enrolled or every endocrine-therapy choice in the trial.
The primary outcome asked how long participants remained alive without documented progression. It is a time-to-event outcome, so it incorporates both the timing of events and the duration of observation. The registry reports median estimates for each treatment group with confidence intervals, but does not report a hazard ratio or a primary-endpoint p-value. The numerical medians therefore describe the observed outcome distributions; they do not, by themselves, establish the size or statistical certainty of a treatment-group difference.
3. Trial Design
This was a randomized, phase III, parallel-group trial with no masking. The National Cancer Institute sponsored the study. The registry lists the study as completed, with enrollment of 394 participants. Its recorded start was 2008-09-24 and its primary completion was 2014-06-30.
Participants were assigned to endocrine therapy with bevacizumab or endocrine therapy alone. Endocrine therapy consisted of tamoxifen citrate or letrozole. In the combination group, bevacizumab was administered intravenously on day 1, alongside oral endocrine therapy on days 1-21. The endocrine-only group received oral endocrine therapy on days 1-21. Both regimens repeated every 21 days while there was no disease progression or unacceptable toxicity. The combination regimen included bevacizumab 15 mg/kg, administered over 30-90 minutes.
Random allocation means assignment was determined by a chance-based process, rather than being chosen solely by clinicians or participants. A parallel design means that assigned groups followed their respective regimens rather than crossing over between trial treatments as part of the described comparison. The record states that masking was absent; it does not describe participants or study personnel as blinded to assignment.
Although the trial enrolled participants choosing either endocrine drug, the stated primary endpoint compared letrozole alone with letrozole plus bevacizumab. The registry says the primary analysis was restricted to participants who elected letrozole. This analysis population included 343 evaluable participants after excluding the 5 who elected letrozole but did not receive treatment. The record does not state whether this was an intention-to-treat, per-protocol, or another formally defined analysis population beyond the description that the primary endpoint analysis was restricted to those electing letrozole and evaluable for the endpoint.
The study also listed secondary outcomes covering progression-free survival at specified times, response, overall survival, duration of response, clinical benefit, and time-to-treatment failure. The registry record does not report values for every listed outcome. Its listed outcome follow-up window for the primary endpoint extended from randomization until progression or death, assessed up to 5 years.
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
| Stage | Arm I (Endocrine Therapy With Monoclonal Antibody) | Arm II (Endocrine Therapy) |
|---|---|---|
| STARTED | 195 | 199 |
| COMPLETED | 195 | 196 |
| NOT COMPLETED | 0 | 3 |
Reasons for not completing this period:
| Reason | Arm I (Endocrine Therapy With Monoclonal Antibody) | Arm II (Endocrine Therapy) |
|---|---|---|
| Withdrawal by Subject | 0 | 3 |
Analysis population for the primary outcome, as defined in the registry: Per protocol, the analysis of the primary endpoint was restricted to patients that elected letrozole as endocrine therapy. Of the 348 patients electing Letrozole, 5 did not receive treatment (1 on Arm I, and 4 on Arm II). This left 343 patients (173 on the Arm I and 170 on Arm II) evaluable for the primary endpoint.
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.
| Characteristic | Unit | Arm I (Endocrine Therapy With Monoclonal Antibody) | Arm II (Endocrine Therapy) | Total |
|---|---|---|---|---|
| Participants analysed | 195 | 196 | 391 | |
| Age, Continuous | years | 55.5 (24.7 to 85.3) | 58.9 (29.0 to 87) | 57.7 (24.7 to 87) |
| Sex: Female, Male: Female | Participants | 195 | 196 | 391 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 195 | 196 | 391 |
| Endocrine Therapy Elected: Letrozole | participants | 174 | 174 | 348 |
| Endocrine Therapy Elected: Tamoxifen | participants | 21 | 22 | 43 |
6. Primary Endpoint
The registry lists the primary outcome as Progression-free Survival, measured over From randomization until disease progression or death whichever occurs first, assessed up to 5 years.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | months |
| Endpoint classification | Time-to-Event Analysis |
Progression-free survival (PFS) measures the time from randomization until disease progression or death, whichever occurs first. It combines two clinically relevant event types into one time-to-event outcome. An analysis of PFS can therefore account for when events occur, rather than reducing follow-up to a simple count of participants with an event at one selected time.
The registry defines progression using RECIST criteria: at least a 20% increase in the sum of the longest diameters of target lesions from baseline or the appearance of new lesions. The primary endpoint description says median PFS was estimated using the Kaplan-Meier method. The median is the estimated time by which half of the analyzed group has experienced progression or death, under the survival-analysis framework. It describes the midpoint of the estimated event-time distribution; it does not describe every participant's experience.
The endpoint is useful for comparing how long participants remain alive without documented progression. However, its interpretation depends on event definitions, follow-up, and the analysis of participants whose event status is not known at the end of observation. The registry gives the endpoint definition and assessment horizon, but does not report detailed censoring rules or additional analysis procedures beyond the Kaplan-Meier estimate.
The recorded median PFS was 20.2 months for the combination group, with a 95% confidence interval of 17.0 to 24.0 months, and 15.6 months for the endocrine-only group, with a 95% confidence interval of 12.9 to 19.7 months. These are group-level estimates with uncertainty intervals. The registry record does not report a hazard ratio or a p-value for this primary comparison, so the medians and their confidence intervals should not be treated as a complete inferential comparison.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
For the letrozole primary-endpoint population, median PFS was 20.2 months in the group receiving endocrine therapy with bevacizumab and 15.6 months in the group receiving endocrine therapy alone. The corresponding 95% confidence intervals were 17.0 to 24.0 months and 12.9 to 19.7 months. These estimates describe the observed time-to-event distributions in the two groups, while the intervals convey uncertainty around each median.
The intervals overlap. Overlap is not, on its own, a formal test of the difference between groups, and the interval endpoints should not be used to calculate a new comparative estimate. The registry record does not report a primary-endpoint hazard ratio, confidence interval for a treatment contrast, or p-value. As a result, the posted primary numbers permit a descriptive reading of the medians, but they do not provide the full reported inferential evidence needed to characterize the comparative effect precisely.
The endpoint analysis was restricted to participants who elected letrozole, rather than all 394 enrolled participants. Within that group, 343 participants were evaluable: 173 in the combination group and 170 in the endocrine-only group. This population definition is central to interpretation. The primary result does not directly summarize the treatment comparison among participants who selected tamoxifen citrate, nor does it necessarily describe the overall enrolled population.
The secondary progression-free survival rates at 6 months and 12 months are numerically higher in the combination group. These are point-in-time estimates and should be distinguished from the primary time-to-event summary. The registry also posts an overall-survival estimate at 36 months that is very similar between groups. The secondary endpoints therefore do not all communicate the same pattern, and their estimates should be read with their uncertainty and the absence of a reported multiplicity plan in mind.
Some secondary comparisons include unadjusted recalculations based on posted summary statistics. Those calculations are not a substitute for the sponsor's full analysis, and the registry's reported analyses list no analyses for these outcomes. The unadjusted p-values should not be treated as definitive confirmatory findings, particularly when multiple secondary outcomes are considered. The registry does not report whether a multiplicity adjustment or a prespecified hierarchy was used.
The record also includes serious adverse event counts by group. They describe safety events recorded during the study, but the available summary does not provide a complete treatment-specific breakdown of the most frequent serious event terms. Safety counts and efficacy endpoints address different questions; neither should be used as a proxy for the other. Taken together, the posted results offer descriptive estimates for the primary outcome, selected secondary outcomes, and serious adverse events, with important limits on comparative inference.
9. Statistical Methods Explained
The primary outcome is a time-to-event measure. Unlike a binary outcome that records whether an event occurred by a fixed date, PFS retains information about the time from randomization to progression or death. This is useful when participants have differing lengths of follow-up or when some participants have not experienced an event by the time their outcome is assessed.
What does a Kaplan-Meier estimate represent?
The registry says the median PFS was estimated using the Kaplan-Meier method. In general, the Kaplan-Meier method estimates the probability of remaining event-free over time while accounting for participants whose follow-up ends before an event is observed. Such participants are commonly treated as censored at their last known event-free time; the registry's specific censoring rules are not reported in the registry record. The method relies on the timing of recorded events and follow-up, rather than treating every participant as if they had identical observation time.
The median is obtained from the estimated survival curve at the point where the estimated proportion remaining free of the event reaches one-half. It is a summary of the event-time distribution, not an estimate of a treatment effect on its own. A contrast between group medians can be informative descriptively, but it does not contain all information about the curves and does not replace a model-based comparison such as a hazard ratio. The registry record does not report a hazard ratio for the primary outcome.
How should the confidence intervals be read?
A confidence interval expresses uncertainty in an estimated quantity. The 95% confidence intervals reported for the group medians give ranges compatible with the data and the estimation procedure under repeated sampling assumptions. They are not ranges containing 95% of individual participant outcomes, and they do not mean there is a 95% probability that the particular interval contains the fixed true value. The registry reports a separate interval for each group median, but does not give a confidence interval for the between-group treatment contrast.
Because those are separate intervals, their overlap or non-overlap is not a substitute for a direct test of the treatment contrast. Formal comparison requires an appropriate comparison statistic and its uncertainty. Neither a primary comparison p-value nor a hazard ratio is reported in the registry record, so those quantities should not be reconstructed from the median estimates.
What does the RECIST definition contribute?
The registry defines progression as at least a 20% increase in the sum of the longest diameters of target lesions from baseline, or the appearance of new lesions. A prespecified operational definition helps make event classification more consistent. The endpoint also counts death as an event, whichever occurs first. The available record does not give further detail about assessment schedules, adjudication procedures, or handling of specific progression-related circumstances.
How do the secondary binary estimates differ?
The 6-month and 12-month PFS rates are estimates at fixed time points. A point-in-time rate describes the estimated proportion remaining free of progression or death at that particular follow-up time; it does not provide the full shape of the event-time curve. The posted rates have 95% confidence intervals. The unadjusted risk-difference calculations compare the groups on an absolute scale, while risk ratios and odds ratios use relative scales. These measures answer related but distinct questions. Their numerical estimates are recalculations from posted summaries, not separately listed sponsor analyses.
A confidence interval around an absolute or relative comparison describes uncertainty in that contrast. For the posted secondary results, unadjusted p-values are reported in the recalculated comparison material, but the registry record lists no reported analyses. Those p-values do not account for the number of endpoints examined unless a multiplicity procedure is used, and no such procedure is reported. The secondary comparisons are consequently more exploratory than a single prespecified primary comparison would be, even though the endpoint names appear in the registry.
Why can over-dispersion matter?
In general, over-dispersion occurs when observed variability exceeds what a statistical model assumes. It can make standard errors too small if the model's variability assumptions are not appropriate, which can lead to confidence intervals that are too narrow and tests that appear more decisive than warranted. This concept is relevant to some types of count-data models, but the registry's reported primary endpoint is a time-to-event outcome estimated by Kaplan-Meier, and the record does not describe an over-dispersion analysis. It should not be assumed that over-dispersion was present or assessed in this trial.
What are the sample-size illustrations?
The planning illustrations use the observed effect as a reference and show hypothetical participants per arm for selected fractions of that observed effect. Their stated assumptions are a two-sided significance level of 0.05, equal allocation, and a normal approximation. These calculations are explicitly not the trial's own design justification. They are planning illustrations, not evidence of the study's observed power, and do not establish that the trial was adequately or inadequately sized. The trial's sample-size justification and the underlying design assumptions are not reported in the registry record.
For time-to-event outcomes, the general determinants of precision include the amount and timing of event information, follow-up, and the comparison method. A count of randomized participants alone does not convey all of that information. The registry's primary results provide group medians and intervals, but not a sponsor-reported hazard ratio or a comparative test. The study's statistical analysis plan, any interim analyses, and detailed methods for missing outcome data are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry identifies one primary endpoint and lists several secondary outcomes. It does not report a multiplicity strategy, such as a testing hierarchy or an adjustment across secondary comparisons. When many outcomes are tested, nominal p-values can overstate the strength of evidence if they are interpreted as though only one comparison had been made. The unadjusted secondary comparisons therefore warrant caution. The record lists no reported analyses for those secondary comparisons, and the posted recalculations should not be confused with a complete sponsor analysis.
The primary endpoint analysis population is described as participants who elected letrozole, with participants who did not receive treatment excluded from the evaluable group. The record does not state whether the remaining analysis was intention-to-treat, per-protocol, or based on another formal analysis-set definition. It also does not specify how participants with missing endpoint data, incomplete follow-up, or deviations from assigned treatment were handled. Those details are important for understanding whether the analysis preserves the benefits of random assignment and how potentially informative missingness might affect the estimates.
The registry describes PFS as assessed from randomization until progression or death, up to 5 years, and provides the event definition. It does not report the detailed censoring rules, how assessment timing was incorporated, or sensitivity analyses for alternative missing-data assumptions. The record also does not report interim analyses or stopping rules. These omissions do not establish that such procedures were absent; they mean their use and details are not reported in the registry record.
The secondary sample-size illustrations are not the trial's design calculation and should not be used to infer observed power or the original rationale for enrollment. The trial's sample-size justification and statistical analysis plan are not reported in the registry record. Without those details, it is not possible to determine from the posted summary alone how the study's planned power, analysis populations, endpoint hierarchy, and missing-data procedures were specified.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Arm I (Endocrine Therapy With Monoclonal Antibody) | 56 | 195 | 28.7% |
| Arm II (Endocrine Therapy) | 30 | 196 | 15.3% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Arm I (Endocrine Therapy With Monoclonal Antibody) | 174 of 195 |
| Arm II (Endocrine Therapy) | 145 of 196 |
Most frequent serious adverse event terms
| Event term | Organ system | Arm I (Endocrine Therapy With Monoclonal Antibody) | Arm II (Endocrine Therapy) |
|---|---|---|---|
| Arthralgia | Musculoskeletal and connective tissue disorders | 24 of 195 | 12 of 196 |
| Hypertension | Vascular disorders | 20 of 195 | 6 of 196 |
| Proteinuria | Renal and urinary disorders | 18 of 195 | 2 of 196 |
| Headache | Nervous system disorders | 13 of 195 | 4 of 196 |
| Nausea | Gastrointestinal disorders | 8 of 195 | 1 of 196 |
| Fever | General disorders | 6 of 195 | 2 of 196 |
| Dyspnea | Respiratory, thoracic and mediastinal disorders | 5 of 195 | 2 of 196 |
| Vomiting | Gastrointestinal disorders | 5 of 195 | 1 of 196 |
| Anorexia | Metabolism and nutrition disorders | 4 of 195 | 1 of 196 |
| Dehydration | Metabolism and nutrition disorders | 4 of 195 | 1 of 196 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Arm I (Endocrine Therapy With Monoclonal Antibody) | Arm II (Endocrine Therapy) |
|---|---|---|---|
| Arthralgia | Musculoskeletal and connective tissue disorders | 137 of 195 | 115 of 196 |
| Hypertension | Vascular disorders | 115 of 195 | 61 of 196 |
| Headache | Nervous system disorders | 85 of 195 | 58 of 196 |
| Proteinuria | Renal and urinary disorders | 93 of 195 | 13 of 196 |
| Fever | General disorders | 24 of 195 | 15 of 196 |
| Fatigue | General disorders | 19 of 195 | 12 of 196 |
| Epistaxis | Respiratory, thoracic and mediastinal disorders | 24 of 195 | 2 of 196 |
| Back pain | Musculoskeletal and connective tissue disorders | 13 of 195 | 7 of 196 |
| Hot flashes | Vascular disorders | 12 of 195 | 8 of 196 |
| Hypersensitivity | Immune system disorders | 13 of 195 | 2 of 196 |
Serious events with the highest arm-level rate: arthralgia (12.3%), hypertension (10.3%), proteinuria (9.2%), headache (6.7%), nausea (4.1%).
The registry reports serious adverse events among 195 participants at risk in the endocrine-therapy-plus-bevacizumab group and 196 at risk in the endocrine-only group. The counts affected were 56 and 30, respectively. These are participant counts, not measures of event severity beyond the registry's serious-adverse-event classification. The summary does not provide a detailed account of how events were collected, assessed, or attributed to treatment.
The listed serious-event terms include arthralgia, hypertension, proteinuria, headache, nausea, and fever, with percentages reported for each term. The available summary does not map those listed term percentages to treatment arms, so they should not be interpreted as arm-specific rates. Nor should the overall counts be treated as a comparison adjusted for follow-up duration or other factors; such an analysis is not reported in the registry record.
Safety counts and efficacy outcomes answer different questions. The serious adverse event figures do not establish a causal effect of treatment, and the registry summary does not provide enough detail for a comprehensive benefit-risk assessment. The record lists no deaths in the serious adverse event summary, but absence of a value is not evidence that no deaths occurred. The death figures are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The posted primary estimates show median PFS of 20.2 months in the letrozole-plus-bevacizumab group and 15.6 months in the letrozole-only group among the described evaluable letrozole population. The confidence intervals describe uncertainty around each median. This is a descriptive account of the registry's reported estimates, not a complete estimate of the comparative treatment effect.
The primary endpoint comparison is limited by the absence of a reported hazard ratio, confidence interval for a treatment contrast, or p-value. Separate median estimates cannot establish the statistical certainty of a group difference. The results also apply to the analyzed participants who elected letrozole, rather than automatically extending to participants choosing tamoxifen citrate or to every participant enrolled. The trial's randomization supports a comparative design, but interpretation still depends on the analysis population, follow-up, event ascertainment, and handling of missing data.
The secondary outcomes add context but do not settle the primary comparison. The time-specific PFS estimates are numerically higher in the combination group, while the posted 36-month overall-survival estimates are very similar. Different outcomes can show different patterns because they measure different events and time points. The absence of a reported multiplicity plan also means the secondary p-values should not be treated as a series of definitive confirmatory tests.
The safety summary records serious adverse events in both groups and provides a list of frequent serious-event terms. It lacks an arm-specific breakdown for those terms and does not include a detailed causal assessment. Consequently, these figures should not be used alone to make a broad judgment about safety or to weigh treatment choices.
Overall, the registry record supports a careful description of the posted outcome estimates and their uncertainty. It does not support a definitive claim about the magnitude or statistical significance of the primary treatment contrast, a conclusion about equivalence, or conclusions about unreported outcomes and analyses. No medical advice follows from these registry summaries.
13. Why This Trial Matters Statistically
This trial illustrates why the endpoint definition and analysis population need to be read together. The study enrolled 394 participants, but the primary analysis was restricted to those who selected letrozole and were evaluable. That distinction determines which population the median PFS estimates describe. A trial's overall enrollment figure alone is not enough to characterize the data underlying its primary result.
It also demonstrates why a time-to-event median is not a complete comparative analysis. The posted group medians and confidence intervals describe each group's estimated event-time distribution, but the registry does not report the primary hazard ratio or a direct treatment-contrast interval and test. Readers can describe the estimates, but should not invent a formal comparison from separate group summaries.
The mix of primary and secondary outcomes further shows how endpoint multiplicity affects interpretation. A pattern in selected secondary results may be informative, but multiple endpoints can yield nominally notable findings by chance. In the absence of a reported testing hierarchy or multiplicity adjustment, the secondary comparisons carry less confirmatory weight. The distinction between sponsor-reported analyses and unadjusted recalculations also matters: recalculations can help readers understand posted summaries, but they do not replace the study's full analysis plan or results.
Finally, sample-size illustrations based on an observed effect are not evidence of the trial's planned power. The design rationale is not reported in the registry record, and an observed-effect illustration cannot retrospectively establish whether the study was capable of detecting a clinically meaningful difference. These distinctions are central to transparent, appropriately limited interpretation of clinical trial results.
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 primary result is restricted to participants electing letrozole, while the overall trial included women receiving either letrozole or tamoxifen citrate. This limits direct generalization of the primary estimate to the full enrolled population and to participants choosing the other endocrine therapy. The record does not provide primary-endpoint results separately for the tamoxifen citrate subgroup.
The registry reports median PFS and a confidence interval for each group, but does not report a primary comparative hazard ratio, confidence interval for the contrast, or p-value. A formal between-group inference therefore cannot be recovered from the posted primary summary alone. The details of the survival analysis beyond Kaplan-Meier estimation are also limited: censoring procedures, additional model assumptions, and sensitivity analyses are not reported in the registry record.
Analysis-set details are incomplete. The record identifies 343 evaluable participants for the primary analysis after 5 letrozole electors did not receive treatment, but does not state a formal analysis-set label or describe how other missing information and protocol deviations were handled. The statistical analysis plan, sample-size justification, interim analyses, and stopping rules are not reported in the registry record.
Several secondary outcomes are listed without numerical results in the posted record. For the available secondary comparisons, unadjusted recalculations do not account for an unreported multiplicity strategy. The overall-survival estimates lack confidence intervals in the posted summary. Safety details are also limited: serious-event counts are reported, but the listed serious-event term percentages are not broken out by treatment arm, and the death values are not reported in the registry record.
These limitations constrain what can be inferred from registry summaries. They do not establish that analyses or procedures were not performed; they identify information that is not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Tamoxifen Citrate or Letrozole With or Without Bevacizumab in Treating Women With Stage IIIB or Stage IV Breast Cancer — NCT00601900.
- Registry record last updated 2026-08-28; status last verified 2026-08.
- Results first posted 2016-08-23.
- 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.
Continue through the Clinical Biostats statistical pathway
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18. Record Summary
NCT00601900 is a completed randomized phase III trial sponsored by the National Cancer Institute. It compared endocrine therapy with or without bevacizumab in women with stage IIIB or stage IV breast cancer. Endocrine therapy was tamoxifen citrate or letrozole. The trial enrolled 394 participants.
The primary endpoint was PFS among participants electing letrozole. The record reports a median of 20.2 months for the combination group and 15.6 months for the endocrine-only group, with separate 95% confidence intervals. It does not report a primary comparative hazard ratio or p-value. Selected secondary outcomes and serious adverse event counts are also posted, but the registry record does not provide complete results or detailed analysis procedures for every listed outcome.
The numerical results are best read as estimates with limitations in the comparative inference, analysis-population detail, multiplicity reporting, and safety breakdown.