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 Chemotherapy With or Without Strontium-89 in Treating Patients With Prostate Cancer (NCT00024167), a randomized phase 3 study. The primary outcome is Overall Survival From Randomization.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00024167 |
| Phase | Phase 3 |
| Condition | Prostate Cancer |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 265 |
| Arms in the primary outcome | 2 |
| Lead sponsor | M.D. Anderson Cancer Center |
| Results posted | Yes |
2. Clinical Question
Population
The trial concerned patients with androgen-independent prostate cancer, described in the registry as having cancer that had spread to bone. The registry lists prostate cancer as the condition. The posted primary outcome estimates include 65 participants in the strontium-89 arm and 62 in the arm without strontium-89; how these analysis counts relate to the registry’s total enrollment of 265 is not reported in the registry record.
Intervention
After induction treatment, the experimental consolidation arm received doxorubicin and strontium-89. The arm description specifies doxorubicin once weekly for 6 weeks and one intravenous dose of strontium-89 at the beginning of chemotherapy.
Comparator
The comparison arm received consolidation doxorubicin without strontium-89. The registry describes doxorubicin as given on the same schedule as in the other consolidation arm.
Primary question
The primary outcome was overall survival from randomization, measured in months. The clinical question was whether the reported survival experience differed between the two consolidation strategies. The registry provides separate median estimates and confidence intervals, but does not report a sponsor’s hazard ratio or a statistical test comparing the arms. The posted estimates therefore describe each arm; they do not by themselves establish whether the observed difference between them is statistically distinguishable from chance.
3. Trial Design
This was a randomized, phase III, parallel-group trial with no masking. Its official title describes a comparison of consolidation therapy with or without strontium-89 following induction chemotherapy in androgen-independent prostate cancer. The registry lists enrollment of 265 and identifies M.D. Anderson Cancer Center as the sponsor. The trial status is terminated. The reason for termination is not reported in the registry record.
The treatment descriptions distinguish induction from consolidation. The record lists induction regimen A, which includes doxorubicin, ketoconazole, vinblastine and estramustine, and induction regimen B, which includes prednisone and docetaxel. It then describes two consolidation arms: doxorubicin plus strontium-89, or doxorubicin without strontium-89. The registry does not explain how the induction regimens were assigned or selected, nor does it provide further protocol detail about treatment sequence beyond the title’s description of consolidation after induction.
The two primary-outcome groups have posted analysis counts of 65 and 62. These counts do not match the total enrollment figure, and the reason for the difference is not reported in the registry record. The primary outcome was followed every 4 weeks from randomization until death, with follow-up extending up to 7 years. The registry reports that overall survival was evaluated using Kaplan-Meier methodology. The start date is recorded as 2002-04 and primary completion as 2014-09; the record does not give more specific dates in these fields.
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 265 participants enrolled - 127 were randomized to either the Sr-89 treatment arm or the no Sr-89 treatment arm and the rest (138 participants) did not qualify for randomization. Of the 138 participants, 5 did not receive any treatment and the rest received only induction treatment. Study was closed prematurely due to issues with accrual.
Overall Study
| Stage | Induction Treatment + Strontium-89 | Induction Treatment + No Strontium-89 |
|---|---|---|
| STARTED | 65 | 62 |
| Induction Treatment Option 1 Completed | 22 | 21 |
| Induction Treatment Option 2 Completed | 43 | 41 |
| COMPLETED | 12 | 15 |
| NOT COMPLETED | 53 | 47 |
Reasons for not completing this period:
| Reason | Induction Treatment + Strontium-89 | Induction Treatment + No Strontium-89 |
|---|---|---|
| Death | 53 | 47 |
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: Of the 265 participants enrolled - 133 participants received only induction treatment and 127 were randomized to either the Sr-89 treatment arm or the no Sr-89 treatment arm. 5 participants never received any treatment.
| Characteristic | Unit | Induction Treatment | Induction Treatment + Strontium-89 | Induction Treatment + No Strontium-89 | Total |
|---|---|---|---|---|---|
| Participants analysed | 133 | 65 | 62 | 260 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 1 | 1 |
| Age, Categorical: Between 18 and 65 years | Participants | 53 | 22 | 23 | 98 |
| Age, Categorical: >=65 years | Participants | 80 | 43 | 38 | 161 |
| Age, Continuous | years | 67 (44 to 85) | 68 (48 to 85) | 67 (8 to 80) | 67 (8 to 85) |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 133 | 65 | 62 | 260 |
| Region of Enrollment: United States | participants | 133 | 65 | 62 | 260 |
6. Primary Endpoint
The registry lists the primary outcome as Overall Survival From Randomization, measured over Followed every 4 weeks from randomization until death, up to 7 years..
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | months |
| Endpoint classification | Time-to-Event Analysis |
Overall survival from randomization measures the time from randomization until death. The registry defines the endpoint in months. Participants who were still alive were censored at their last follow-up date, meaning their observed survival time contributes information up to that date without treating them as having died then.
Overall survival is a time-to-event endpoint: both whether an event occurred and how long participants were followed matter. It is often useful in randomized trials because death is a clearly defined event and the analysis can incorporate participants with different follow-up durations. In general, censoring is necessary when the event time is not observed during follow-up; interpreting the resulting estimates also depends on how follow-up and censoring operate.
The registry reports a median overall survival estimate for each arm, with a 95% confidence interval. A median is the estimated time by which half of the survival distribution has experienced the event, according to the analysis method. It is not the average survival time and does not describe every participant’s outcome. The endpoint description does not identify a planned primary analysis population or a formal between-arm comparison method beyond the use of Kaplan-Meier methodology to evaluate overall survival.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry reports a median overall survival of 24.2 months for induction treatment plus strontium-89, with a 95% confidence interval from 19.8 to 29.8 months. For induction treatment without strontium-89, it reports a median of 22.8 months, with a 95% confidence interval from 17.7 to 27.7 months. These are arm-specific estimates of the time-to-death distribution, not estimates of how much an individual participant’s life was extended by treatment.
The confidence intervals communicate uncertainty around each median estimate. In general, a confidence interval reflects the precision of an estimate under the statistical method used; it is not a range containing every participant’s survival time. The intervals are broad, and the registry does not provide a sponsor-reported hazard ratio, confidence interval for a between-arm contrast, or p-value. The registry’s analysis field contains no posted analysis entries. Accordingly, the available record does not establish whether the arm-level estimates differ statistically, and a direct test should not be inferred from the two medians or their intervals alone.
The primary outcome counts attached to these estimates are 65 for the strontium-89 arm and 62 for the arm without strontium-89. The record separately lists overall enrollment of 265. It does not explain how the outcome analysis counts relate to enrollment, whether any participants were excluded from this analysis, or what analysis population was intended. These counts should not be treated as a complete account of trial participation or follow-up.
The registry also names overall survival from registration as a secondary outcome, but it does not post a result for that outcome in the record. The primary endpoint is explicitly overall survival from randomization, so its time origin differs from the secondary outcome’s named time origin. No estimate for the secondary outcome should be inferred from the primary result.
The record states that the trial was terminated but does not report why, when the decision was made, or whether termination affected follow-up or the planned analyses. The posted survival estimates remain descriptive results in this record. Without a reported comparative analysis and supporting analysis details, they do not determine the strength of evidence for a difference between the consolidation strategies.
9. Statistical Methods Explained
The primary endpoint is time to death measured from randomization. In general, time-to-event methods are designed for outcomes where participants may have different lengths of follow-up and where some participants have no recorded event by the end of observation. A participant alive at last follow-up contributes information through that point and is censored there, as described in this registry record.
What does Kaplan-Meier estimation do?
The registry says Kaplan-Meier methodology was used to evaluate overall survival. In general, this method estimates the probability of remaining event-free over time while accounting for censored observations. It updates the estimated survival experience at observed event times, rather than requiring every participant to have the same follow-up duration. The reported median is read from the estimated survival curve at the point where estimated survival reaches one half. The record does not include the curves or enough detail to reconstruct their shape from the medians alone.
The method relies on assumptions about how censoring relates to the outcome. In general, estimates can be difficult to interpret if people lost to follow-up differ in their future event experience from those who remain observed, unless the analysis appropriately addresses that difference. The record describes censoring alive participants at last follow-up but does not report the amount or pattern of censoring, reasons for loss to follow-up, or additional methods for handling missing outcome information.
How should the confidence intervals be read?
The registry reports 95% confidence intervals for both medians. In general, a confidence interval conveys sampling uncertainty around an estimated quantity under the analysis method and its assumptions. It does not indicate the range of individual survival times, and it is not a guarantee that a particular interval contains the underlying value. The confidence intervals reported for the arms are 19.8 to 29.8 months and 17.7 to 27.7 months. Separate arm-level intervals are not a substitute for an interval around a direct treatment contrast.
For a comparative time-to-event question, a hazard ratio is one possible summary of the relative event rate over follow-up, subject to its assumptions and interpretation. No sponsor-reported hazard ratio appears in the registry record. The record also has no posted analysis entries and does not report a comparative test, a p-value, or an interval for a between-arm effect. As a result, the evidence available in the registry record is limited to arm-specific medians and their intervals for this primary endpoint.
What can the sample-size illustration establish?
The registry describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It states that the effect to detect is a stated fraction of the observed effect. Such calculations are planning illustrations, not evidence about the trial’s observed statistical power, and they do not show that a study was designed or conducted according to those assumptions. The calculations are not the trial’s own design justification. The registry record does not report the trial’s sample-size justification or the actual planning inputs used by the investigators.
For a time-to-event outcome, planning commonly depends on the number of events as well as enrollment and follow-up. In general, this is because information about a survival contrast accumulates as events occur. The registry’s description says time-to-event planning outputs refer to a total number of events, whereas other planning outputs refer to participants per arm. The numerical planning outputs are not reported in the registry record. No additional value should be inferred from the fact that overall enrollment is recorded.
What analytical details remain unspecified?
The endpoint description identifies Kaplan-Meier methodology, but the registry does not report a model for a comparative treatment effect, adjustment variables, handling of protocol deviations, or the primary analysis population. It also does not report whether the proportional-hazards assumption was assessed. In general, such details matter when interpreting a comparative survival analysis: a single hazard ratio, for example, may not summarize the treatment contrast adequately if relative hazards vary over time. No such assessment or model result is available in the record.
The registry says the trial was randomized and parallel, but does not provide allocation concealment details or further information on the randomization procedure. The masking entry is none. The available record therefore supports a basic description of the design and endpoint estimation, but not a full reconstruction of the analysis plan or the rationale behind all analytic choices.
10. Multiplicity, Missing Data and Analysis Populations
The registry names overall survival from randomization as the primary outcome and overall survival from registration as a secondary outcome. It reports two outcome measures, but only one secondary outcome is named in the record. A result for that secondary outcome is not reported in the registry record. No multiplicity strategy is reported, including whether the trial controlled the overall type I error across outcomes or other comparisons. Without that information, the primary endpoint result should not be interpreted as part of a defined hierarchy of statistical tests.
Missing-data information is limited. The primary endpoint description states that participants alive at last follow-up were censored at that date. This is a specified feature of the survival analysis, but it does not describe the extent of incomplete follow-up, the reasons participants may not have been observed, or sensitivity analyses for informative censoring. Those details are not reported in the registry record.
The outcome population field is blank, and no intention-to-treat or other analysis population is identified. The primary-outcome groups list 65 participants for the strontium-89 arm and 62 for the arm without it, while total enrollment is 265. The record does not explain this difference or specify whether all randomized participants were included in the endpoint analysis. The number of analyses is recorded as zero, and no comparative test, hazard ratio, or p-value is posted. The trial’s statistical analysis plan and the handling of withdrawals or protocol deviations are not reported in the registry record.
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 |
|---|---|---|---|
| Induction Treatment | 77 | 138 | 55.8% |
| Induction Treatment + Strontium-89 | 53 | 65 | 81.5% |
| Induction Treatment + No Strontium-89 | 47 | 62 | 75.8% |
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 |
|---|---|
| Induction Treatment | 34 of 138 |
| Induction Treatment + Strontium-89 | 12 of 65 |
| Induction Treatment + No Strontium-89 | 13 of 62 |
Most frequent serious adverse event terms
| Event term | Organ system | Induction Treatment | Induction Treatment + Strontium-89 | Induction Treatment + No Strontium-89 |
|---|---|---|---|---|
| Death | General disorders | 77 of 138 | 53 of 65 | 47 of 62 |
| Neutrophil Count Decreased | Blood and lymphatic system disorders | 1 of 138 | 4 of 65 | 0 of 62 |
| Fatigue | General disorders | 3 of 138 | 1 of 65 | 0 of 62 |
| Lymphopenia | Infections and infestations | 2 of 138 | 1 of 65 | 1 of 62 |
| Hemoglobin Decreased | Blood and lymphatic system disorders | 3 of 138 | 0 of 65 | 0 of 62 |
| Pain | General disorders | 2 of 138 | 1 of 65 | 0 of 62 |
| Urinary Tract Infection | Infections and infestations | 1 of 138 | 1 of 65 | 0 of 62 |
| Infection with Grade 3 or 4 Neutrophils | Infections and infestations | 2 of 138 | 0 of 65 | 0 of 62 |
| Infection | Infections and infestations | 1 of 138 | 1 of 65 | 0 of 62 |
| Bone Pain | Musculoskeletal and connective tissue disorders | 2 of 138 | 0 of 65 | 0 of 62 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Induction Treatment | Induction Treatment + Strontium-89 | Induction Treatment + No Strontium-89 |
|---|---|---|---|---|
| Fatigue | General disorders | 16 of 138 | 11 of 65 | 5 of 62 |
| Pain | General disorders | 18 of 138 | 7 of 65 | 7 of 62 |
| Nausea | Gastrointestinal disorders | 11 of 138 | 2 of 65 | 5 of 62 |
| Edema Limbs | Blood and lymphatic system disorders | 8 of 138 | 5 of 65 | 2 of 62 |
| Constipation | Gastrointestinal disorders | 10 of 138 | 3 of 65 | 2 of 62 |
| Hemoglobin Decreased | Blood and lymphatic system disorders | 6 of 138 | 4 of 65 | 4 of 62 |
| Dyspnea | Respiratory, thoracic and mediastinal disorders | 8 of 138 | 2 of 65 | 3 of 62 |
| Peripheral Sensory Neuropathy | Nervous system disorders | 8 of 138 | 2 of 65 | 1 of 62 |
| Pain in Extremity | Musculoskeletal and connective tissue disorders | 4 of 138 | 2 of 65 | 3 of 62 |
| Bone Pain | Musculoskeletal and connective tissue disorders | 4 of 138 | 2 of 65 | 2 of 62 |
Serious events with the highest arm-level rate: death (81.5%), neutrophil count decreased (6.2%), hemoglobin decreased (2.2%), fatigue (2.2%), musculoskeletal (1.6%).
The safety record lists serious adverse events for three groups: induction treatment, induction treatment plus strontium-89, and induction treatment without strontium-89. For these groups, the record gives, respectively, 77 of 138, 53 of 65, and 47 of 62 participants as affected by serious adverse events. It also lists other adverse events affecting 34 of 138, 12 of 65, and 13 of 62 participants, respectively. These are the counts and at-risk denominators as recorded; no additional percentages have been calculated.
The registry’s listed top serious-event terms include Death at 81.5%, Neutrophil Count Decreased at 6.2%, Hemoglobin Decreased at 2.2%, Fatigue at 2.2%, Musculoskeletal at 1.6%, and Lymphopenia at 1.6%. The record does not identify the denominator or clarify how these percentages relate to the group-level affected counts. It also does not report deaths as a separate count in the safety groups. These figures should therefore be read as registry-listed safety summaries, not as a direct comparison of risk between randomized arms. Definitions, attribution, and any overlap between event categories are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The posted results describe median overall survival in the two consolidation arms and provide a confidence interval around each median. The reported medians are 24.2 months with strontium-89 and 22.8 months without it. Those estimates summarize each arm’s survival distribution from randomization; they are not a direct estimate of the causal effect of adding strontium-89, nor do they describe the experience of every participant.
A treatment comparison requires an estimate of the difference between arms and its uncertainty, or another prespecified comparative analysis. The registry does not report a hazard ratio, a confidence interval for a treatment contrast, or a p-value. The arm medians and their separate confidence intervals cannot replace those results. Therefore the registry record alone does not show whether the observed arm-level survival estimates represent a statistically reliable difference.
The record establishes that the study was randomized, phase III, parallel, and unmasked, and that the primary endpoint was evaluated with Kaplan-Meier methodology. It does not provide the full analysis plan, the reason the trial was terminated, or an explanation of how the analysis counts relate to total enrollment. It also does not report a result for the named secondary survival outcome. These gaps limit assessment of the planned comparisons, the completeness of outcome reporting, and the precision of any conclusion about the treatment contrast.
In general, statistical evidence and clinical interpretation are related but distinct. A median and its confidence interval describe the estimated timing of an event in a group, while a comparative analysis addresses the uncertainty in a difference between groups. The available posted results support the first kind of description, but do not provide enough information for the second. No claim about treatment benefit or lack of benefit follows from these registry data alone.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of how a registry may report a time-to-event outcome without reporting a direct comparative estimate. The primary endpoint is overall survival from randomization, and Kaplan-Meier methodology is identified. The posted medians and confidence intervals show the scale and uncertainty of the arm-specific summaries, but not the uncertainty of the contrast that addresses the randomized question.
That distinction matters in reading randomized studies. A comparison based on separate group estimates can appear straightforward, yet the statistical question concerns the difference between groups. In general, an interval around each group’s estimate does not provide the same information as an interval around the treatment effect. The absence of a posted hazard ratio, comparative test, and p-value means that a reader cannot recover the reported inferential conclusion from this record.
The record also illustrates why denominators and analysis populations matter. Enrollment is recorded as 265, while the primary outcome entries list counts of 65 and 62. Safety summaries use additional group-specific denominators. The registry does not reconcile these figures. They may reflect different reporting scopes, but the reason is not reported and should not be assumed.
Finally, the terminated status, absent analysis entries, missing secondary outcome result, and limited information about missing follow-up leave important uncertainties about reporting and interpretation. These features do not invalidate the posted estimates; they define what can be concluded from the registry record. Careful statistical reading separates the descriptive survival summaries from evidence about the comparative effect of the two consolidation strategies.
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 registry provides a limited account of the trial’s statistical analysis. It reports Kaplan-Meier evaluation for overall survival, but no comparative test, hazard ratio, or between-arm confidence interval. The population field for the primary outcome is blank, and the record does not identify an intention-to-treat or other analysis set. The reason the outcome counts differ from total enrollment is not reported in the registry record.
Follow-up is described as occurring every 4 weeks from randomization until death, up to 7 years, with participants alive censored at last follow-up. The record does not state how many participants had incomplete follow-up, how much censoring occurred, or whether censoring differed between arms. It does not report sensitivity analyses, missing-data procedures beyond censoring, or details about withdrawals and protocol deviations.
The trial status is terminated, but the reason and timing of termination are not reported. The registry does not explain whether termination affected enrollment, follow-up, or planned analyses. It also does not provide the sample-size justification, full statistical analysis plan, randomization procedure details, allocation concealment, or a multiplicity strategy. The named secondary outcome has no posted result. These omissions prevent a complete assessment of the prespecified analysis and the completeness of outcome reporting.
Finally, the safety summaries have distinct group denominators and list adverse-event terms, but their exact relationship to the randomized outcome groups and the percentage denominator for the listed serious-event terms are not reported. Safety counts should be interpreted within those reporting limits rather than as a fully documented comparative safety analysis.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Chemotherapy With or Without Strontium-89 in Treating Patients With Prostate Cancer — NCT00024167.
- Registry record last updated 2016-03-22; status last verified 2016-02.
- Results first posted 2016-03-22.
- 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 describes NCT00024167 as a randomized, unmasked, parallel-group phase III trial of consolidation chemotherapy with or without strontium-89 after induction chemotherapy for androgen-independent prostate cancer. It lists enrollment of 265, M.D. Anderson Cancer Center as sponsor, and a terminated status.
The primary endpoint was overall survival from randomization, assessed using Kaplan-Meier methodology. Median estimates were 24.2 months for the strontium-89 arm and 22.8 months for the arm without strontium-89, with reported 95% confidence intervals of 19.8 to 29.8 months and 17.7 to 27.7 months. No comparative analysis result or hazard ratio is posted. The reason for termination, analysis population, relationship between enrollment and outcome counts, and result for the named secondary outcome are not reported in the registry record.