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 Comparison of Two Combination Chemotherapy Regimens Plus Radiation Therapy in Treating Patients With Stage III or Stage IV Endometrial Cancer (NCT00006011), a randomized phase 3 study. The primary outcome is Recurrence-Free Survival of Eligible Patients Who Received a Random Treatment Allocation..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00006011 |
| Phase | Phase 3 |
| Condition | Endometrial Adenocarcinoma, Endometrial Adenosquamous Carcinoma, Endometrial Clear Cell Adenocarcinoma |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 659 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Gynecologic Oncology Group |
| Results posted | Yes |
2. Clinical Question
Population
The trial concerned patients with stage III or stage IV endometrial cancer, including the endometrial cancer types listed in the registry record. The primary outcome description narrows its analysis population to eligible participants who received a random treatment allocation. The record gives a total enrollment of 659, but does not provide further participant characteristics in the information available for this analysis.
Intervention
Arm 1 received doxorubicin and cisplatin, with filgrastim or pegfilgrastim support. Its treatment description specifies doxorubicin intravenously on day 1 followed by cisplatin intravenously on day 1, with growth-factor support on days 2-11. Radiation therapy is part of the trial’s stated treatment comparison, but the arm description does not provide its schedule or individual assignment details.
Comparator
Arm 2 received doxorubicin and cisplatin as in Arm 1, with paclitaxel added on day 2 and filgrastim or pegfilgrastim support on days 3-12. Treatment was described as repeating every 3 weeks for a maximum of 6 courses when disease progression or unacceptable toxicity had not occurred. The registry title also frames the study as comparing tumor-volume-directed pelvic irradiation with or without para-aortic irradiation.
Primary question
The central statistical question is whether recurrence-free survival differed between the randomized treatment groups among eligible participants who received a random allocation. Recurrence-free survival is defined from randomization, and recurrence is described using clinical, radiographic, or laboratory evidence or a stated increase in lesion size. The record does not report a single numerical between-group estimate, its uncertainty, or a test result for this outcome.
3. Trial Design
This was a randomized phase III trial with a parallel-group design and double masking, according to the registry record. The recorded enrollment was 659. The sponsor was the Gynecologic Oncology Group. The record lists the trial start as 2000-07, primary completion as 2010-03, and status as completed. These details describe the registered study; they do not by themselves establish how closely every aspect of conduct followed the registry entry.
The comparison involved two combination chemotherapy regimens in the setting of radiation therapy for stage III or stage IV endometrial cancer. Both arms included doxorubicin and cisplatin. The distinguishing chemotherapy component in Arm 2 was paclitaxel, given on day 2; the growth-factor support schedule also differed between the arm descriptions. Arm 1 listed filgrastim or pegfilgrastim support on days 2-11, while Arm 2 listed support on days 3-12. The record states that treatment repeats every 3 weeks for a maximum of 6 courses in the absence of disease progression or unacceptable toxicity.
The official title describes tumor-volume-directed pelvic irradiation with or without para-aortic irradiation, followed by the chemotherapy alternatives. The available arm descriptions do not specify the radiation assignment process, dose, or timing. The registry record also does not report the allocation ratio, the details of sequence generation or concealment, the masking procedures, or the roles of masked parties. Randomized, double-masked, and parallel are the recorded design labels, but the operational methods behind those labels 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
| Stage | Arm 1 | Arm 2 | Radiation (RT) Only |
|---|---|---|---|
| STARTED | 288 | 298 | 73 |
| COMPLETED | 223 | 221 | 0 |
| NOT COMPLETED | 65 | 77 | 73 |
Reasons for not completing this period:
| Reason | Arm 1 | Arm 2 | Radiation (RT) Only |
|---|---|---|---|
| Disease progression | 13 | 6 | 26 |
| Refused further treatment | 15 | 13 | 26 |
| Adverse Event | 15 | 39 | 5 |
| Death | 0 | 1 | 2 |
| Other | 4 | 2 | 5 |
| Ineligible | 18 | 16 | 9 |
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.
Population: Total number of eligible participants.
| Characteristic | Unit | Arm 1 | Arm 2 | Radiation (RT) Only | Total |
|---|---|---|---|---|---|
| Participants analysed | 270 | 282 | 64 | 616 | |
| Age, Continuous | years | 58.8 (SD 11.1) | 58.8 (SD 9.5) | 63.9 (SD 10.7) | 59.3 (SD 10.5) |
| Sex: Female, Male: Female | Participants | 270 | 282 | 64 | 616 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Recurrence-Free Survival of Eligible Patients Who Received a Random Treatment Allocation., measured over study entry up to 5 years post treatment.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary outcome is titled recurrence-free survival among eligible participants who received a random treatment allocation. It is defined as the time in months that a participant is alive and recurrence-free, starting from the date of randomization. The outcome timeframe is study entry up to 5 years post treatment. Recurrence is described as discovery of disease not previously present by clinical, radiographic, and/or laboratory means, or as a 50% or greater increase in the product of two perpendicular diameters from a documented lesion.
Time-to-event outcomes are useful when both whether an event occurs and when it occurs matter. They can distinguish an event occurring earlier from one occurring later, and can account for participants whose event status is not observed through the entire follow-up period, provided the analysis uses an appropriate method and handles censoring appropriately. Those are general properties of time-to-event analysis; the specific method used in this trial is not reported in the registry record.
The registry identifies the primary outcome as recurrence-free survival, but the posted result information does not give a single numerical estimate or contrast for it. It therefore does not support a numerical conclusion about the size, direction, or precision of a difference between arms.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies recurrence-free survival as the primary outcome and defines its population as eligible participants who received a random treatment allocation. It also describes how recurrence was determined and gives the follow-up timeframe as study entry up to 5 years post treatment. These details establish what the endpoint was intended to represent, but they are not themselves a report of the observed outcome.
The posted results do not provide a single numerical comparison for recurrence-free survival. The record indicates that the primary outcome has several categories or time points and was not reduced to one comparison. As a result, no between-arm effect estimate, confidence interval, p-value, event count for the primary outcome, or group-specific recurrence-free survival value is available in the record information used for this explanation. The direction and size of any difference, and the precision with which it might have been estimated, therefore cannot be interpreted.
This absence matters because a trial design and a primary endpoint definition do not establish what the trial found. A randomized comparison can support an estimate of a treatment contrast when the outcome data and analysis are reported, but the registry entries alone do not reveal that contrast. Enrollment, treatment descriptions, and trial completion status are not substitutes for outcome estimates.
The other statistical material should also be interpreted within its limits. General explanations of uncertainty, event-time analysis, and planning assumptions describe statistical concepts, not additional clinical findings. Any planning illustration based on a fraction of an observed effect is hypothetical; it is not a measure of the trial’s observed power. The registry record does not report the original sample-size justification or a prospective statistical plan against which a planning calculation could be checked.
The serious adverse event counts are descriptive safety information. They should not be treated as a randomized estimate of comparative safety without details about event definitions, collection, follow-up, and analysis. The registry lists serious affected counts and additional adverse-event counts for each arm, alongside selected serious-event terms and percentages. These entries do not establish why events occurred or whether one regimen caused more harm than the other.
In short, the record establishes the randomized comparison and the endpoint definition but does not provide a single interpretable primary outcome contrast. Any claim about which arm had better recurrence-free survival, or by how much, would go beyond the posted results.
9. Statistical Methods Explained
Statistical methods translate observed outcome data into estimates of a treatment contrast and descriptions of uncertainty. For this trial, the registry record supplies a randomized design label and a time-to-event primary endpoint definition, but the specific methods used to analyze that endpoint are not reported in the registry record. General statistical concepts can clarify what would ordinarily be needed to interpret such a comparison without implying that a particular method was used in this study.
What does a time-to-event endpoint represent?
A time-to-event outcome records the time from a defined starting point until an event, such as recurrence or death, according to the endpoint definition. Here, the stated starting point is randomization, and recurrence-free survival is defined as time alive and recurrence-free. The time-to-event framing preserves timing information rather than reducing every participant’s course to a simple event/no-event label. It also raises an analysis issue: some participants may have follow-up ending before an event is observed. In general, those observations may be censored, meaning that the event time is not known beyond the last observed time. Appropriate methods must account for such incomplete event-time information.
Why is a confidence interval useful?
In general, a confidence interval expresses the uncertainty around an estimated effect under the assumptions of the statistical method. An estimate alone gives a central value; the interval indicates which effect sizes remain compatible with the data and method at the stated confidence level. A narrow interval generally indicates greater precision than a wide interval, though precision is not the same as clinical importance. No primary-outcome confidence interval is reported in the registry information, so the precision of the treatment contrast cannot be assessed.
What can a p-value tell a reader?
In general, a p-value measures how incompatible the observed data are with a specified null hypothesis under a particular statistical model. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. Its interpretation depends on the analysis specification, including the outcome definition, population, model, and handling of missing or censored observations. The registry record does not report a primary-outcome p-value or the associated statistical model, so no significance conclusion can be drawn from it.
Why might a time-to-event analysis use a model?
General approaches to time-to-event analysis can compare event-time distributions or estimate a relative event rate over follow-up. Model-based estimates depend on assumptions about how the event rates relate over time and how censoring occurs. If an assumption is unsuitable, a single summary may not represent the full pattern over time. The record does not identify which approach was used, state model assumptions, or report checks of those assumptions. It is therefore not possible to attribute a specific estimate or modeling choice to this trial.
What does the planning illustration mean?
The stated planning assumptions describe an illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation between the arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. These are planning assumptions, not evidence that the original trial was designed using those assumptions. A sample-size illustration answers a hypothetical question about the size of a future study under specified assumptions; it is not observed power and does not establish that the trial had adequate power. The registry record does not report the trial’s own sample-size justification, target effect, or design calculation.
Interpreting any planning calculation also requires knowing what outcome and effect measure it uses. For time-to-event outcomes, the record’s stated convention is that planning displays give the total number of events. Other planning displays are described as participants per arm. Such figures are not observed outcome counts. Their usefulness depends on the assumptions being relevant to a future design and on the underlying effect estimate being sufficiently reliable. The registry information does not provide a primary-outcome effect estimate from which readers could independently assess that reliability.
Why does over-dispersion matter in general?
Over-dispersion occurs when observed variability exceeds what a statistical model assumes. In general, underestimating variability can make standard errors too small and uncertainty intervals too narrow, while accounting for extra variability can better reflect the data’s scatter. This concept is relevant to some count outcomes, but the available registry information does not report an over-dispersion assessment or identify a count model for the primary endpoint. It should not be mistaken for a method used in this trial.
More broadly, a complete statistical interpretation requires the analysis population, endpoint coding, model, effect estimate, uncertainty interval, and treatment of incomplete observations. Randomization supports a comparative design, but does not replace transparent reporting of the analysis. Those primary analysis details are not reported in the registry record, so the methods discussion can describe general principles but cannot reconstruct the trial’s statistical analysis.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome description includes a follow-up timeframe extending to 5 years post treatment, while the registry record notes that the outcome has several categories or time points and was not reduced to one comparison. When investigators examine several time points, outcome categories, or treatment contrasts, the chance of finding at least one apparently notable result can increase. In general, multiplicity procedures can address that issue, but the choice depends on the planned family of comparisons and the inferential goal. The registry record does not report a multiplicity plan, a hierarchy of outcomes, or which comparisons were prespecified.
The record does not report how missing outcome data were handled, how censoring was defined in the analysis, or whether sensitivity analyses were conducted. For time-to-event outcomes, these details affect which participants contribute information at each time and how incomplete follow-up is represented. General methods can make assumptions about the relationship between censoring and event risk; readers need the analysis description to judge whether those assumptions are plausible.
The endpoint description names eligible participants who received random treatment allocation as the analysis population. It does not fully specify the eligibility criteria, exclusions after randomization, or whether every randomized participant was included in the outcome analysis. The phrase “intention to treat” appears in the outcome description, but the record does not provide enough detail to verify how that principle was implemented. No interim analyses, stopping boundaries, or statistical analysis plan are reported in the registry record. These omissions limit assessment of how analysis choices and incomplete data may affect interpretation.
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 1 | 10 | 261 | 3.8% |
| Arm 2 | 21 | 278 | 7.6% |
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 1 | 259 of 261 |
| Arm 2 | 278 of 278 |
Most frequent serious adverse event terms
| Event term | Organ system | Arm 1 | Arm 2 |
|---|---|---|---|
| Thrombosis/Embolism | Vascular disorders | 0 of 261 | 4 of 278 |
| Neutrophils/Granulocytes | Blood and lymphatic system disorders | 0 of 261 | 3 of 278 |
| Cns Cerebrovascular Ischemia | Nervous system disorders | 1 of 261 | 1 of 278 |
| Supraventricular Arrhythmias | Cardiac disorders | 0 of 261 | 2 of 278 |
| Abdominal Pain or Cramping | General disorders | 1 of 261 | 1 of 278 |
| Diarrhea (without Colostomy) | Gastrointestinal disorders | 0 of 261 | 2 of 278 |
| Nausea | Gastrointestinal disorders | 1 of 261 | 1 of 278 |
| Dehydration | Gastrointestinal disorders | 0 of 261 | 1 of 278 |
| Circulatory or Cardia, Other | Cardiac disorders | 0 of 261 | 1 of 278 |
| Hypotension | Cardiac disorders | 0 of 261 | 1 of 278 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Arm 1 | Arm 2 |
|---|---|---|---|
| Leukopenia | Blood and lymphatic system disorders | 190 of 261 | 250 of 278 |
| Neutropenia | Blood and lymphatic system disorders | 158 of 261 | 236 of 278 |
| Alopecia | Skin and subcutaneous tissue disorders | 185 of 261 | 179 of 278 |
| Anemia | Blood and lymphatic system disorders | 137 of 261 | 205 of 278 |
| Constitutional | General disorders | 105 of 261 | 133 of 278 |
| Nausea | Gastrointestinal disorders | 89 of 261 | 95 of 278 |
| Thrombocytopenia | Blood and lymphatic system disorders | 55 of 261 | 116 of 278 |
| Other Pain | General disorders | 63 of 261 | 101 of 278 |
| Other Gastrointestinal | Gastrointestinal disorders | 73 of 261 | 88 of 278 |
| Vomiting | Gastrointestinal disorders | 75 of 261 | 79 of 278 |
Serious events with the highest arm-level rate: thrombosis/embolism (1.4%), neutrophils/granulocytes (1.1%), supraventricular arrhythmias (0.7%), diarrhea (without colostomy) (0.7%), cns cerebrovascular ischemia (0.4%).
The registry lists serious adverse events for Arm 1 as 10 participants affected among 261 at risk, and for Arm 2 as 21 participants affected among 278 at risk. It also lists other adverse events affecting 259 of 261 at risk in Arm 1 and 278 of 278 at risk in Arm 2. These are posted counts, not adjusted comparisons. No rates or differences are calculated.
The record lists thrombosis/embolism at 1.4%, neutrophils/granulocytes at 1.1%, supraventricular arrhythmias at 0.7%, diarrhea (without colostomy) at 0.7%, CNS cerebrovascular ischemia at 0.4%, and abdominal pain or cramping at 0.4% among the top serious-event terms. These percentages are registry entries; the information does not specify their denominators or give arm-specific values for each term. They should not be read as comparative risks between the arms.
Safety interpretation also depends on how events were defined, collected, graded, and followed, as well as whether participants could experience more than one event. Those details and a formal comparative safety analysis are not reported in the registry record. Counts alone do not establish cause, severity beyond the registry classification, or whether a difference between arms is meaningful.
12. What the Result Does, and Does Not, Mean
The registry record describes a randomized phase III comparison of two chemotherapy regimens used with radiation therapy for stage III or stage IV endometrial cancer. Both regimens included doxorubicin and cisplatin; Arm 2 also included paclitaxel. The primary endpoint was recurrence-free survival among eligible participants who received a random treatment allocation, with recurrence defined using clinical, radiographic, laboratory, or lesion-size criteria.
Those details establish the study question and the intended outcome, but the posted results do not provide a single numerical primary-outcome comparison. Without an effect estimate and its uncertainty, readers cannot determine the direction, size, or precision of a difference in recurrence-free survival. The registry record therefore cannot support a claim that either regimen had better or worse recurrence-free survival.
Similarly, the listed serious adverse event counts and selected event-term percentages are descriptive entries. The record does not give enough detail to interpret them as causal effects or as a complete comparative safety analysis. They should be read as reported safety information, not as proof that one regimen is safer or more hazardous.
General statistical explanations and planning assumptions can help readers understand what estimates, confidence intervals, and design calculations mean. They do not fill in missing trial results. In particular, sample-size illustrations based on fractions of an observed effect are planning exercises, not observed power and not evidence about what the trial found. The original sample-size justification and analysis plan are not reported in the registry record.
The distinction is between a clearly stated clinical question and an answer supported by reported outcome data. The record provides the former and important design and safety details, but not the single primary-outcome estimate needed to quantify the treatment contrast. Conclusions should remain within that boundary.
13. Why This Trial Matters Statistically
This trial illustrates why a registry entry’s design information and its outcome reporting need to be read separately. Randomization and a parallel-group comparison describe how treatments were intended to be compared. They do not, on their own, reveal the observed treatment effect. For a primary endpoint such as recurrence-free survival, a useful statistical report needs to show an estimate, its uncertainty, and enough detail about the analysis to explain how follow-up and incomplete observations were handled.
The outcome definition also matters. Recurrence-free survival combines being alive and free of recurrence over time, and the record specifies both the starting point and recurrence criteria. Clear definitions help readers understand what an endpoint captures and how it differs from a simple count of events. Yet a definition cannot show whether the groups’ outcome patterns differed; that requires reported comparative results.
The registry notes multiple categories or time points without reducing the primary outcome to one comparison. That makes transparent reporting of planned contrasts and multiplicity especially relevant. Without a stated analysis plan, readers cannot tell how the selected comparisons relate to the broader set of possible comparisons. The record also leaves key analysis details unreported, including missing-data handling and the statistical method.
Finally, the serious adverse-event information demonstrates the difference between descriptive counts and an inferential safety comparison. Counts provide a record of events under the registry’s reporting scheme, but their meaning depends on definitions, exposure, follow-up, and analysis. Taken together, the trial is statistically instructive because it presents a defined randomized question while leaving the principal numerical outcome comparison unavailable in the registry record.
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 main trial-specific limitation for interpretation is that the registry information does not present a single numerical comparison for the primary outcome. It names recurrence-free survival, defines recurrence, and gives a timeframe, but the record notes several categories or time points and does not reduce them to one comparison. No primary-outcome estimate, confidence interval, or p-value is reported in the information.
Several details needed to assess the conduct and analysis are also not reported in the registry record. These include the full eligibility criteria, allocation ratio and implementation, details of masking, the statistical model, censoring rules, handling of missing data, multiplicity procedures, interim analyses, and the statistical analysis plan. The registry’s “intention to treat” wording does not by itself show how the analysis population was constructed or whether all randomized participants were included.
The safety information has its own constraints. Serious and other adverse event counts are listed by arm, and selected serious-event terms have percentages, but definitions, collection procedures, follow-up duration, arm-specific term counts, and the denominators for the percentages are not specified in the information used. These data cannot establish comparative safety or causation.
The record’s trial status is completed, but completion does not resolve the absence of an interpretable primary-outcome contrast. The stated planning assumptions are illustrative and do not replace the original sample-size rationale or establish the trial’s achieved statistical power. These limitations apply to what can be concluded from the registry record, not necessarily to analyses or reports that are not described in it.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Comparison of Two Combination Chemotherapy Regimens Plus Radiation Therapy in Treating Patients With Stage III or Stage IV Endometrial Cancer — NCT00006011.
- Registry record last updated 2015-05-19; status last verified 2015-04.
- Results first posted 2014-06-26.
- 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.
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18. Record Summary
The registry record describes a completed, randomized, double-masked, parallel-group phase III trial sponsored by the Gynecologic Oncology Group, with enrollment of 659. It compared two chemotherapy regimens in the context of radiation therapy for stage III or stage IV endometrial cancer. Both arms included doxorubicin and cisplatin; paclitaxel was listed in Arm 2.
The primary outcome was recurrence-free survival among eligible participants who received a random treatment allocation, measured from randomization and defined using survival and recurrence criteria. The record gives a timeframe of study entry up to 5 years post treatment but does not report a single numerical primary-outcome comparison. Serious adverse event counts and selected serious-event terms are listed, though the information does not support a formal comparative safety conclusion. Key statistical analysis details are not reported in the registry record.