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 Sorafenib Tosylate and Gene Expression Analysis in Patients Undergoing Surgery For High-Risk Localized Prostate Cancer (NCT00466752), a non-randomized phase 2 study. The primary outcome is Efficacy as Assessed by Number of Patients With Changes Across Transcript Profiles by Microarray Analysis in Prostate Cancer Specimens, Specifically Those With Complete Pathologic Response..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00466752 |
| Phase | Phase 2 |
| Condition | Adenocarcinoma of the Prostate, Stage II Prostate Cancer, Stage III Prostate Cancer |
| Allocation | Non-Randomized |
| Design model | Sequential |
| Masking | None (open label) |
| Enrollment | 5 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Washington |
| Results posted | Yes |
2. Clinical Question
Population
Patients with high-risk localized prostate cancer undergoing radical prostatectomy. The listed conditions include adenocarcinoma of the prostate and stage II and stage III prostate cancer. The registry reports an enrollment of 5; it does not give further characteristics of the enrolled participants.
Intervention
Sorafenib tosylate taken by mouth twice daily on days 1–14, with treatment repeated every 2 weeks for 3 courses if disease progression or unacceptable toxicity did not occur. The study also included laboratory analyses of blood and tumor tissue, including gene-expression methods.
Comparator
The registry describes groups with different intervals between the end of sorafenib and surgery: a 48-hour drug stop and a 24-hour drug stop. Allocation was non-randomized and unmasked. These groups are not a like-for-like randomized control comparison.
Primary question
The primary outcome description concerns changes in transcript profiles in prostate cancer specimens before versus after treatment, assessed by microarray analysis, and the proportion of patients with complete pathologic response. The registry lists the primary outcome population as data not collected, and reports no analyses.
In practical terms, the study was intended to examine tissue-level changes associated with sorafenib before prostate surgery, alongside complete pathologic response. The record also lists secondary outcomes concerning complete pathologic response and a reduction in PSA of at least 25%. It does not report results for those outcomes. Because the study was non-randomized, the stop-point groups cannot be treated as exchangeable groups assigned by chance. Any observed differences between them would not, by themselves, show that the timing of the drug stop caused those differences. In this record, there are no outcome analyses from which to describe such differences.
3. Trial Design
This was a phase II study sponsored by the University of Washington. The registry lists the study as completed, with a start date of 2006-12 and primary completion in 2010-04. Total enrollment is listed as 5. The allocation was non-randomized, masking was absent, and the model was sequential. No further rationale for those design choices is reported in the registry record.
The treatment descriptions specify sorafenib tosylate by mouth twice daily on days 1–14, repeated every 2 weeks for 3 courses if there was no disease progression or unacceptable toxicity. Radical prostatectomy was planned for approximately day 43. The described groups differ in the interval between completing sorafenib and surgery: one specifies surgery beginning 2 days after treatment and the other specifies 1 day after treatment. The registry does not describe a randomized assignment procedure or a separate untreated control group. The two drug-stop groups therefore should not be read as randomized treatment and control arms.
The listed study activities also include needle biopsy, conventional surgery, microarray analysis, gene-expression analysis, immunohistochemistry, western blotting, and laboratory biomarker analysis. These describe procedures or investigations; they do not, by themselves, provide outcome results. Although the primary outcome description refers to pre- versus post-treatment specimens and a minimum 50 day interval, the treatment description places surgery at approximately day 43. The record does not reconcile these timing details.
The enrollment total is small, but the registry does not report a sample-size justification or the intended precision for the outcomes. It also does not report the number enrolled in each drug-stop group in the main study description. The adverse-event record lists 5 participants at risk in the 48-hour group and none in the 24-hour group, but those entries should not be used to fill in unreported details of the analysis population. No statistical analysis results are listed.
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: Five subjects were screened for this study, deemed eligible and enrolled.
Overall Study
| Stage | 48 Hour Drug Stop Point | 24 Hour Drug Stop Point |
|---|---|---|
| STARTED | 5 | 0 |
| COMPLETED | 5 | 0 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Data not collected
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 | 48 Hour Drug Stop Point | 24 Hour Drug Stop Point | Total |
|---|---|---|---|---|
| Participants analysed | 5 | 0 | 5 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 4 | 0 | 4 |
| Age, Categorical: >=65 years | Participants | 1 | 0 | 1 |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 5 | 0 | 5 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 4 | 0 | 4 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 5 | 0 | 5 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | Participants | 5 | — | 5 |
| Baseline PSA | ng/mL | 14.76 (6.14 to 120.76) | — | 14.76 (6.14 to 120.76) |
| Gleason Score at Diagnosis | units on a scale | 7 (7 to 9) | — | 7 (7 to 9) |
6. Primary Endpoint
The registry lists the primary outcome as Efficacy as Assessed by Number of Patients With Changes Across Transcript Profiles by Microarray Analysis in Prostate Cancer Specimens, Specifically Those With Complete Pathologic Response., measured over Pre- versus post-treatment.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is described as efficacy assessed through changes across transcript profiles in prostate cancer specimens, measured by microarray analysis before and after treatment, together with the proportion of patients with complete pathologic response. Transcript profiles describe patterns of gene activity in sampled tissue. A before-and-after comparison can be used to characterize how those measured patterns differ across treatment periods. Complete pathologic response is a tissue-based outcome assessed in the surgical specimen; it is distinct from a change in a laboratory marker or a symptom outcome.
These measures address different questions. Transcript-profile changes are biological measurements, while complete pathologic response records a pathologic finding after treatment. Including both can provide complementary descriptions of tissue response, but neither measure alone establishes a patient-centered benefit. Interpretation depends on how specimens were collected, how changes were defined, and how participants were included in the analysis. Those details are not reported in the registry record.
The record does not provide a numerical endpoint result, an estimate of the proportion with complete pathologic response, or a definition of the transcript-profile change used for analysis. It lists the primary outcome population as data not collected and reports no analyses. Consequently, the endpoint description identifies what the study intended to measure, not what the study found.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record is informative about the intended study question and the treatment schedule, but it does not provide an analyzable primary outcome result. The primary outcome population is listed as data not collected, and the count of analyses is 0. No estimate of transcript-profile change, complete pathologic response, or uncertainty around either outcome is reported. The listed secondary outcomes also have no reported results. As a result, the posted record cannot establish the size, direction, or precision of any effect.
The enrollment of 5 is important context for the scope of the study. Even if an outcome count or tissue measurement had been available, a small study would generally provide limited precision, and individual observations could have substantial influence. That general statistical consideration does not substitute for an actual estimate or interval. No confidence interval or other measure of uncertainty is reported for the primary or secondary outcomes.
The study's non-randomized allocation also limits comparisons between the 48-hour and 24-hour drug-stop groups. In a randomized comparison, assignment by chance is intended to balance prognostic factors on average. Non-randomized groups may differ for reasons related to enrollment, clinical circumstances, timing, or other factors. The registry does not report enough information to assess whether such differences arose or how they were handled. The groups are explicitly not a like-for-like control comparison, so their labels should not be interpreted as indicating a causal contrast.
The treatment description places radical prostatectomy at approximately day 43, while the primary outcome description states a minimum 50 day interval between pre- and post-treatment specimens. The record does not explain how those timing statements relate to one another. This prevents a clear reconstruction of the intended specimen schedule from the registry alone. It is not appropriate to resolve that ambiguity by assuming an unreported protocol detail.
The adverse-event record lists no participants with serious adverse events among 5 at risk in the 48-hour group. It lists no participants at risk in the 24-hour group, so the zero entries there do not demonstrate an absence of events among participants who received treatment. The record does not report death counts, and it gives no serious adverse-event terms. These entries are descriptive registry counts, not a complete comparative safety analysis.
Planning calculations associated with a sample-size section, if considered, are illustrations based on an observed effect and specified assumptions, not evidence that the trial was designed or powered that way. The registry supplies no outcome estimate on which to base an observed treatment effect in this study. Such calculations are not observed power and cannot restore results that were not collected or reported.
9. Statistical Methods Explained
Several statistical ideas help clarify what the registry can and cannot support. The first is the distinction between an outcome definition and an outcome result. A definition says what investigators intended to measure; a result requires observed participant data and an analysis. Here, the primary outcome is described in terms of transcript profiles and complete pathologic response, but the outcome population is listed as data not collected and the registry reports 0 analyses. The outcome description therefore cannot be read as evidence that a response occurred or that transcript profiles changed.
What does a confidence interval communicate?
In general, a confidence interval describes the uncertainty around an estimated quantity under the assumptions of the analysis. A narrow interval indicates greater statistical precision than a wide interval, while an interval spanning a broad range of plausible values signals substantial uncertainty. An interval does not correct bias in a non-randomized comparison, and it does not make an inadequately defined endpoint interpretable. No confidence interval is reported for this study's primary or secondary outcomes, so their precision cannot be assessed from the record.
Why does allocation matter?
Random allocation is a design method for reducing systematic differences between comparison groups. With non-randomized allocation, group membership may be related to participant characteristics or other factors that also relate to outcomes. Statistical adjustment can sometimes address measured differences, but it cannot guarantee removal of unmeasured confounding. The registry does not report a randomization procedure, adjustment methods, or an analysis comparing the two drug-stop groups. The stop-point groups should therefore not be interpreted as if randomization had made them comparable.
What is the limitation of a before-and-after measurement?
A before-and-after tissue comparison can describe changes observed over time in the sampled material. Without a suitable comparison and a clearly reported analysis, it cannot distinguish changes associated with treatment from changes related to measurement, sampling, timing, or other events. The registry does not specify how transcript-profile changes were summarized, what threshold would count as a meaningful change, or how variability across measured genes was handled. Microarray analysis can involve many measured features; in general, the more features examined, the more important it is to define the analysis and account for the possibility of chance findings. No such statistical details are reported.
What do the sample-size illustrations mean?
In general, sample-size planning calculations describe how many participants might be needed under assumptions about the effect to detect, variability, significance level, allocation, and statistical method. The record describes a planning illustration based on the observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. It says the target effect is a stated fraction of the observed effect; it also distinguishes event totals for time-to-event calculations from participants per arm for other calculations. These are planning assumptions, not evidence of the original study's design justification. The registry does not report that justification. Since the primary outcome population is recorded as data not collected and there are no analyses, the record does not establish an observed effect for interpreting a study-specific planning illustration. Sample-size calculations are not observed power and do not show whether a result is statistically significant.
Why can over-dispersion matter?
In general, over-dispersion occurs when count data vary more than a statistical model expects. If it is ignored, standard errors may be too small and uncertainty may be understated. This matters only when a relevant count outcome and model are being analyzed. The registry does not report a count-data model or an over-dispersion assessment, and the absence of outcome analyses means there is no basis to evaluate either issue for this study.
How should significance tests be read?
In general, a p-value describes how incompatible the observed data are with a specified statistical null model, under the analysis assumptions. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. Interpretation also depends on the analysis plan, endpoint definition, and multiplicity. No p-values or inferential analyses are reported in the registry record, so there is no significance test to interpret.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary outcome and two secondary outcomes: number of participants with complete pathologic response and number with at least 25% reduction in PSA. It does not report a multiplicity strategy, such as designating a single confirmatory comparison, adjusting significance thresholds, or treating secondary outcomes as exploratory. When several outcomes or many transcript features are examined, the chance of at least one chance-positive finding can increase. In general, prespecifying analyses and addressing multiplicity can help readers distinguish confirmatory findings from exploratory patterns. The registry does not provide the statistical plan needed to assess that distinction.
Missing-data handling is not reported in the registry record. More fundamentally, the primary outcome population is explicitly listed as data not collected, and the record reports 0 analyses. It does not explain whether outcome data were never collected, were unavailable for reporting, or were excluded for another reason. Those possibilities should not be conflated. No imputation approach, missingness assessment, or sensitivity analysis is reported.
The analysis populations are also not described. The record does not state which participants contributed to each endpoint, whether analyses were based on treatment received or another population definition, or how participants who did not complete treatment or surgery would be handled. There are no reported participant-level outcome counts with which to assess these issues. Accordingly, the reader cannot determine how missingness, endpoint multiplicity, or analysis-population choices affected the results.
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 |
|---|---|---|---|
| 48 Hour Drug Stop Point | 0 | 5 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| 48 Hour Drug Stop Point | 5 of 5 |
| 24 Hour Drug Stop Point | 0 of 0 |
Most frequent non-serious adverse event terms
| Event term | Organ system | 48 Hour Drug Stop Point | 24 Hour Drug Stop Point |
|---|---|---|---|
| voice changes/dysarthria | Respiratory, thoracic and mediastinal disorders | 4 of 5 | 0 of 0 |
| Hypertension | Vascular disorders | 4 of 5 | 0 of 0 |
| Fatigue | General disorders | 3 of 5 | 0 of 0 |
| Diarrhea | Gastrointestinal disorders | 2 of 5 | 0 of 0 |
| Alopecia | Skin and subcutaneous tissue disorders | 2 of 5 | 0 of 0 |
| Hand-foot syndrome | Skin and subcutaneous tissue disorders | 2 of 5 | 0 of 0 |
| Pruritis | Skin and subcutaneous tissue disorders | 2 of 5 | 0 of 0 |
| Rash | Skin and subcutaneous tissue disorders | 2 of 5 | 0 of 0 |
| Tinnitus | Ear and labyrinth disorders | 1 of 5 | 0 of 0 |
| Constipation | Gastrointestinal disorders | 1 of 5 | 0 of 0 |
The registry separates serious adverse events from other adverse events. For the 48 Hour Drug Stop Point group, it lists 5 participants at risk and 0 affected by a serious adverse event. It also lists 5 at risk and 5 affected by other adverse events. These are counts, not rates adjusted for follow-up time, and the registry does not give event descriptions for the other-event count in this record.
For the 24 Hour Drug Stop Point group, the registry lists 0 participants at risk and 0 affected in both categories. A zero denominator means no participants are represented as at risk in that group in these adverse-event entries; it should not be interpreted as evidence that participants in that group had no events. The study enrollment is listed as 5 overall, but the record does not explain the relationship between that total and the group-specific adverse-event entries.
The death count is not reported. No serious adverse-event terms are listed. These entries do not provide enough information for a comparative safety assessment, and they should not be treated as a complete account of all possible harms.
12. What the Result Does, and Does Not, Mean
The record documents a phase II study of sorafenib before radical prostatectomy, with planned assessment of tissue gene-expression changes and complete pathologic response. It also documents a treatment schedule and two described intervals between the end of sorafenib and surgery. The registry's non-randomized design and small enrollment are important context for interpreting any comparison between those stop-point groups.
The record does not report the primary outcome data or analyses. It therefore does not establish whether transcript profiles changed, how many participants had complete pathologic response, or what the uncertainty around any such finding would be. The listed secondary outcomes likewise have no reported results. No conclusion about treatment effect can be drawn from endpoint descriptions alone.
Statistically, this distinction is central: a study can state a biologically interesting question and collect methods intended to investigate it, while the registry record still lacks the data needed to estimate an effect. The absence of a reported analysis is not evidence that an effect was absent, nor is it evidence that an effect was present. It leaves the size and direction of the outcomes unknown from this record.
The non-randomized stop-point groups also cannot establish that one timing strategy caused a different outcome from the other. Any causal interpretation would require adequate outcome data and a design or analysis capable of addressing differences between groups. The registry does not report such an analysis. The most defensible reading is therefore descriptive: the record states what the study planned to examine and gives limited safety counts, but it does not provide an interpretable estimate of efficacy or a full comparative safety result.
13. Why This Trial Matters Statistically
This study illustrates why a registry description and a results record answer different statistical questions. The design description identifies the population, treatment schedule, timing around surgery, and planned biological measurements. Those details help readers understand the intended inquiry, but they do not supply estimates of outcomes. In this case, the primary outcome population is recorded as data not collected and the analysis count is 0, making the distinction especially clear.
The study also highlights the limits of comparing non-randomized groups. Different intervals between drug completion and surgery may be scientifically relevant, but the allocation method does not provide the protections of randomization. Without a reported analysis and information on group composition, a difference between groups could not be attributed confidently to the timing interval.
A further statistical lesson is that biological measurements and clinical or pathologic outcomes are not interchangeable. Transcript-profile analysis may describe molecular patterns, while complete pathologic response is a distinct tissue outcome and PSA reduction is another endpoint. Each needs a clear definition, an analysis population, and a reported estimate with appropriate uncertainty. Multiplicity and missing-data handling also matter when several outcomes or many molecular features are considered, yet those methods are not reported.
Finally, planning illustrations should be read as conditional calculations rather than evidence about what a trial actually observed. When outcomes are not reported, planning assumptions cannot stand in for results. This record therefore offers a useful example of how design, endpoint definition, allocation, reporting completeness, and statistical inference must be considered together.
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.
Several limitations specific to this study constrain interpretation. Enrollment is listed as 5, and the registry does not report detailed participant characteristics or group sizes in the main study description. The non-randomized allocation and lack of masking further limit the interpretation of any comparison between the drug-stop groups. The record itself cautions that the groups are not a like-for-like control comparison.
The most substantial reporting limitation is the absence of primary outcome data: the outcome population is listed as data not collected, and no analyses are reported. Results for the listed secondary outcomes are also absent. The registry does not report confidence intervals, p-values, or other measures of precision. It is consequently not possible to assess the magnitude or reliability of outcome findings.
Important analysis details are not reported in the registry record, including a sample-size justification, endpoint operational definitions, analysis populations, handling of missing data, multiplicity procedures, and any adjustment for differences between groups. The description of a minimum 50 day interval between specimens is not reconciled with the plan for surgery at approximately day 43. The adverse-event record includes a 24-hour group with no participants listed at risk, and the death count is not reported. Together, these omissions limit assessment of efficacy, safety, and the intended timing of specimen collection.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Sorafenib Tosylate and Gene Expression Analysis in Patients Undergoing Surgery For High-Risk Localized Prostate Cancer — NCT00466752.
- Registry record last updated 2017-11-22; status last verified 2017-11.
- Results first posted 2017-11-22.
- 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.
Continue through the Clinical Biostats statistical pathway
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18. Record Summary
NCT00466752 is a completed, non-randomized, unmasked phase II study sponsored by the University of Washington. It enrolled 5 participants and examined sorafenib tosylate before radical prostatectomy for high-risk localized prostate cancer. The treatment descriptions differ in whether the drug was stopped 48 hours or 24 hours before surgery.
The primary outcome description concerns pre- versus post-treatment transcript profiles and complete pathologic response. The registry lists the primary outcome population as data not collected and reports 0 analyses. It also lists secondary outcomes for complete pathologic response and PSA reduction of at least 25%, without reported results. Serious adverse-event entries list 0 affected among 5 at risk in the 48-hour group; the 24-hour group has 0 participants listed at risk. Deaths are not reported. The record therefore describes the study's intent and limited safety counts but does not provide an efficacy estimate or a randomized comparison.