Carboplatin Plus Docetaxel (Taxotere) in Anaplastic Prostate Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Carboplatin Plus Docetaxel (Taxotere) in Anaplastic Prostate Cancer (NCT00514540), a na phase 2 study. The primary outcome is Median Time to Progression (TTP).

2. Clinical Question

The study asked about time to progression among patients with anaplastic prostate cancer receiving first-line carboplatin plus docetaxel. The registry summary also describes a second-line question: how effective etoposide plus cisplatin is for patients whose advanced disease continues. Side effects, characteristics of patients who respond, and overall survival were also stated as study interests.

The primary endpoint was time to progression, defined as the time from registration on study until disease progression. The registry specifies assessment at the end of course 1 and course 2, followed by assessments every 2 months for progression. It also describes follow-up every 6 months and an overall study period of six and half years. The primary outcome entry gives a median and a 95% confidence interval as the intended summary, but neither the numerical median nor its interval is reported in the registry record.

3. Trial Design

The registry identifies this as a phase II study sponsored by M.D. Anderson Cancer Center. It lists an enrollment of 121 and describes a single-group model, no masking, and allocation as NA. The study status is completed. The listed start was 2006-05, and primary completion was 2013-04.

The first-line regimen is carboplatin with docetaxel. The arm description specifies carboplatin area under the curve (AUC) = 5, given intravenously over 30 minutes, and docetaxel 75 mg/m² given intravenously over 60 minutes on Day 1, repeated every 3 weeks. The study summary says that patients who continued to have advanced disease would switch to etoposide plus cisplatin as second-line chemotherapy. The second-line description begins with etoposide 120 mg/m² daily for 3 days and cisplatin 25 mg/m² for 3 days, but the registry’s arm description is incomplete after that detail. The remaining regimen instructions are not reported in the registry record.

This design does not assign participants to concurrent randomized groups. The second-line group represents patients who proceeded to that treatment after first-line chemotherapy, rather than a separate control group assigned at study entry. The registry explicitly cautions that the arms are not a like-for-like control comparison. Consequently, a contrast between their outcomes or adverse-event counts would not isolate the effect of one regimen relative to the other.

The registry describes disease-status evaluation at the end of course 1, up to 84 days after day 1 of cycle 1, and at the end of course 2, up to 168 days after day 1 of cycle 1. It also records later progression assessments and follow-up, but does not report the actual analysis dates or results. The protocol details, eligibility criteria, and reasons for any participants not represented in the adverse-event risk sets 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.

Before assignment: Of the 121 participants enrolled, seven were ineligible and excluded. Another participant was eligible but withdrew before treatment.

First-Line Chemo

Reasons for not completing this period:

Second-Line

Reasons for not completing this period:

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: Eligibile population treated.

6. Primary Endpoint

The registry lists the primary outcome as Median Time to Progression (TTP), measured over Baseline to evaluation at end of course 2 (up to 168 days) then every 2 months for disease progression. Follow up every 6 months and overall study period was six and half years..

The primary endpoint, median time to progression (TTP), is defined as the time from registration on study until disease progression. It summarizes the point in the observed time-to-event distribution by which half of the analyzed group has experienced the event, subject to how censoring and event status are handled in the analysis. The registry lists a 95% confidence interval for the median as its measure of uncertainty.

Time-to-event endpoints are useful when the timing of an event matters and participants may have different lengths of follow-up. In general, participants without a recorded progression at their last assessment can contribute information up to that time without being treated as though progression occurred then. The validity of such an analysis depends on appropriate event definitions, follow-up, and handling of censoring. The registry defines progression and gives planned assessment timing, but does not report the detailed analysis procedure or censoring rules.

The recorded assessment plan included evaluation at the end of course 1 and course 2, then every 2 months for progression, with follow-up every 6 months. The primary outcome timeframe also describes an overall study period of six and half years. The numerical median TTP and its 95% confidence interval are not reported in the registry record, so the endpoint’s estimated timing and precision cannot be described from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The record names median time to progression as the primary outcome and a 95% confidence interval as its dispersion measure. It does not report the numerical median, interval limits, event count for this endpoint, or the method used to estimate it. The following concepts are general explanations of how such statistics are commonly interpreted; they do not establish which analysis procedures were used in this study.

What does a median time-to-event result convey?

In general, a median time-to-event estimate describes the time by which half of the analyzed population is estimated to have experienced the defined event. It is a summary of the event-time distribution, rather than a statement that every participant experienced the event at that time. Here, the event is disease progression, and the origin is registration on study. The registry’s definition supplies those elements, but does not report the estimated median.

Time-to-event analyses can account for participants whose event has not been observed by the end of their available follow-up. Such observations are commonly treated as censored at the last known event-free time. Censoring allows the available follow-up to contribute information without asserting that an event occurred. How censoring was defined and handled in this study is not reported in the registry record. The recorded assessment schedule also means that progression could be identified at scheduled evaluations rather than at an exactly observed biological onset; the record does not describe how this timing was addressed analytically.

How should a confidence interval be read?

In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the method used. A narrower interval indicates greater statistical precision than a wider interval, while an interval does not remove potential bias from study design, measurement, or missing follow-up. The 95% confidence interval listed for median TTP cannot be interpreted numerically because its endpoints are not reported in the registry record. A confidence interval is not a guarantee that the true value lies within the particular calculated interval, and it does not by itself establish clinical importance.

What does the study design allow?

A single-group study describes outcomes in the participants who received the study regimen; it does not by itself estimate what would have happened to a comparable group under an alternative treatment. Random allocation, when used, can help balance prognostic factors across treatment groups. This record lists allocation as NA and the model as single-group, so no randomized contrast is described. The first-line and second-line chemotherapy groups are sequential and the latter consists of patients who continued to have advanced disease. Their treatment histories and selection differ, so comparisons between their outcomes are not equivalent to comparisons between concurrently assigned groups.

The absence of masking is recorded as NONE. Masking can reduce the influence of expectations on some aspects of care, assessment, or reporting, depending on who is masked and how outcomes are measured. The registry does not report further masking procedures or whether progression assessments were independently reviewed. It is not possible to infer additional safeguards from the masking entry.

What analysis details are unavailable?

The record describes the primary endpoint and timing of assessment but does not report a statistical analysis plan, the estimator used for median TTP, an inferential test, covariate adjustment, or rules for censoring and analysis populations. It also does not report interim analyses or how missing outcome assessments were handled. These are distinct methodological details: knowing the endpoint definition does not reveal the statistical method used to produce its estimate.

The record lists two outcome measures and one analysis, but the second outcome measure and the scope of that analysis are not detailed in the available entries. The registry does not report a numerical primary result, so no recalculated summary can be compared with a sponsor analysis. General methods cannot fill in a missing result or demonstrate that an analysis was performed in a particular way.

The safety counts require a separate interpretation from the time-to-progression endpoint. The registry reports the numbers at risk and numbers affected for serious and other adverse events, plus deaths. These entries do not provide event-level follow-up, exposure duration, attribution, or a comparative estimate. In a sequential, nonrandomized study, the second-line group is also selected by prior disease course. Thus the counts are descriptive and do not establish a causal difference between regimens.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures, but the available record does not describe the second measure in detail or report a multiplicity strategy. Multiplicity arises when several outcomes, comparisons, or analyses are examined: the chance of at least one apparently notable result can increase when many statistical questions are tested. Methods such as prespecifying a primary endpoint or adjusting inference can address particular multiplicity concerns, but the registry record does not report whether such procedures were planned or used. The primary endpoint is identified as median time to progression.

The statistical analysis plan, analysis populations, and handling of missing data are not reported in the registry record. In general, missing outcome assessments can reduce the information available and may bias an estimate if the reasons for missingness are related to prognosis or event status. For time-to-event outcomes, censoring rules and the timing of last adequate assessment matter. The record gives an assessment schedule but does not state how missed assessments, withdrawals, or incomplete follow-up were treated.

The enrollment is listed as 121, while the adverse-event entries give 113 at risk in the first-line group and 74 at risk in the second-line group. The record does not explain the relationship between these risk-set counts and total enrollment, nor report the numbers contributing to the primary endpoint analysis. No assumptions about exclusions or missing outcomes can therefore be made from the counts alone.

The record also does not report interim analyses, stopping rules, or a sample-size justification. Their presence, absence, and rationale cannot be inferred. Any additional detail about multiplicity control, missing-data procedures, or analysis-set definitions is not reported in the registry record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: cellulitis (2.7%), phlebitis (2.7%), platelets (2.7%), thrombosis/embolism (2.7%), infection (2.7%).

The registry reports serious adverse events for the first-line carboplatin plus docetaxel group as 18 affected among 113 at risk, and for the second-line etoposide plus cisplatin group as 10 among 74 at risk. For other adverse events, the entries are 112 among 113 at risk in the first-line group and 58 among 74 at risk in the second-line group. Deaths are listed as 3 and 1, respectively. These are descriptive counts associated with the registry’s group entries.

The serious-event terms listed most prominently are cellulitis, phlebitis, platelets, thrombosis/embolism, infection, and vomiting, each at 2.7%. The record does not give further event-level detail alongside these terms. In particular, the listed counts do not show when events occurred, whether individuals experienced more than one event, or whether the investigator considered an event related to study treatment.

The at-risk groups are not randomized comparison groups. The second-line group followed first-line treatment and was intended for patients with continuing advanced disease. Differences in counts cannot therefore be attributed to a difference between the chemotherapy regimens. The record also does not explain why the at-risk counts are smaller than total enrollment. These safety entries should be read as reported counts, not as a controlled estimate of comparative risk.

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

The registry record documents a completed phase II, single-group study of first-line carboplatin plus docetaxel in anaplastic prostate cancer, with etoposide plus cisplatin described for second-line treatment when advanced disease continued. It defines time to progression as the primary endpoint and specifies disease-assessment timing. It also reports adverse-event counts and selected serious-event terms.

Those details do not establish how long participants remained free of progression. The numerical median TTP and 95% confidence interval are not reported in the registry record. The record also does not provide a numerical comparison with an alternative treatment. A stated research objective to study effectiveness is not itself evidence of an estimated effect.

The single-group design describes outcomes in people treated within the study but does not supply the counterfactual outcome under another approach. The first-line and second-line groups are sequential rather than like-for-like controls; patients reaching second-line therapy were selected based on continuing advanced disease. Consequently, the safety counts should not be read as comparative evidence that one regimen has more or fewer adverse events than the other.

In general, a confidence interval helps convey precision around an estimate, but the listed confidence level alone cannot show precision when its limits and the estimate are absent. Similarly, adverse-event counts describe recorded events but do not establish causation or comparative risk without additional design and analysis information. The registry entry is useful for understanding the study’s aims, treatment sequence, endpoint definition, and posted safety data. The unreported results and methods prevent stronger conclusions about progression timing, treatment effects, or relative safety.

13. Why This Trial Matters Statistically

This study illustrates why a clearly defined endpoint and an interpretable design matter alongside the treatment description. The registry defines progression as the event and registration as the time origin, then describes when disease status was to be assessed. Those details help identify what the endpoint is intended to measure. However, without the numerical median and its 95% confidence interval, readers cannot assess the observed time-to-progression estimate or its precision.

The single-group structure also shapes the questions the data can answer. Outcomes observed in one treatment group can describe the experience of enrolled participants, but cannot independently distinguish treatment effects from other influences on disease course. The later second-line group is particularly unsuitable as a direct comparator because it follows first-line therapy and includes patients whose advanced disease continued. This is a design distinction, not a matter that can be repaired by comparing counts alone.

The record also demonstrates the importance of reporting analysis details. An endpoint definition and assessment schedule do not tell readers how censoring, missed assessments, analysis populations, or multiple outcomes were handled. Such information affects how an estimate should be understood and how robustly it can be interpreted. These elements are not reported in the registry record.

Finally, safety summaries require context. Counts and listed event terms are informative descriptions, but do not show treatment attribution or allow a fair comparative inference across sequential groups. The record’s value is therefore in documenting the planned clinical questions and selected observed safety entries, while its limits are central to any statistical reading.

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 most direct limitation for interpreting efficacy is that the registry record does not report the numerical primary endpoint result. Although median TTP and a 95% confidence interval are identified, neither the estimate nor interval is available. A numerical hazard ratio is also not reported in the record. The primary result therefore cannot be described or assessed for precision.

The study is listed as single-group, with allocation recorded as NA and masking as NONE. It does not describe a randomized concurrent control group. The registry specifically cautions that the two chemotherapy groups are not a like-for-like control comparison. The second-line group follows first-line treatment and is intended for patients with continuing advanced disease, making direct comparisons especially vulnerable to differences in prognosis and treatment history.

The total enrollment is 121, while the adverse-event entries give 113 and 74 at risk for the first-line and second-line groups. The record does not explain the relationship between enrollment and these group counts or report the primary endpoint analysis population. It also does not describe missing-data handling, censoring rules, participant withdrawals, or the extent of follow-up for individual participants.

Additional limitations include the absence of a reported statistical analysis plan, sample-size justification, interim-analysis details, and multiplicity procedures. The second-line regimen description is incomplete in the registry entry. The safety data lack event-level detail and treatment attribution. These unreported elements restrict the conclusions that can be drawn from the registry record; they should not be replaced by assumptions about the protocol or analysis.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Carboplatin Plus Docetaxel (Taxotere) in Anaplastic Prostate Cancer — NCT00514540.
• Registry record last updated 2020-09-01; status last verified 2020-08.
• Results first posted 2020-09-01.
• 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.

18. Record Summary

NCT00514540 is a completed phase II, single-group study sponsored by M.D. Anderson Cancer Center, with enrollment listed as 121. It examined first-line carboplatin plus docetaxel in patients with anaplastic prostate carcinoma and described etoposide plus cisplatin for second-line chemotherapy in patients with continuing advanced disease.

The primary endpoint was median time to progression, defined from study registration to disease progression. The registry gives assessment timing and specifies a 95% confidence interval, but does not report the numerical median or interval. Safety entries include serious and other adverse-event counts and deaths for the listed treatment groups. Because the groups are sequential and not like-for-like controls, those counts do not constitute a randomized safety comparison. Analysis methods, missing-data procedures, and the statistical plan are not reported in the registry record.