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 Vitamin D in Treating Patients With Prostate Cancer (NCT00524680), a randomized phase 2 study. The primary outcome is Pattern of Response of Serum 25(OH) D3 Levels.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00524680 |
| Phase | Phase 2 |
| Condition | Prostate Cancer |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 148 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Roswell Park Cancer Institute |
| Results posted | Yes |
2. Clinical Question
Population
Patients with prostate cancer were eligible for the study. The primary outcome population is described as all treated and eligible patients. The registry record does not report the eligibility criteria or explain how eligibility and treatment status were determined for the outcome analyses.
Intervention
Participants were assigned to daily oral cholecalciferol, also described as vitamin D3, at one of four dose levels: 4,000 IU, 6,000 IU, 8,000 IU, or 10,000 IU. The registry describes the intervention as a dietary supplement.
Comparator
The comparison is among the four assigned dose levels. The record does not describe a placebo group, usual-care group, or untreated control group. It therefore addresses variation in response across dose assignments rather than a comparison of supplementation with no supplementation.
Primary question
The stated primary outcome is the pattern of response in serum 25(OH) D3 levels. The record describes change from baseline at 1, 3, and 6 months across the 4,000 IU, 6,000 IU, 8,000 IU, and 10,000 IU dose levels. The central statistical question is how serum levels changed from baseline at those follow-up times within the dose levels. The registry says a one-sample t-test was used, but it does not report the numerical changes, their standard deviations, confidence intervals, or test results. It also does not report a single summary contrast that ranks the doses or estimates a difference between dose groups. Consequently, the study question can be described from the outcome definition, but its primary numerical findings cannot be reconstructed from the registry record.
3. Trial Design
This is a randomized, parallel-group phase II study of oral cholecalciferol in patients with prostate cancer. The record describes four dose arms: 4,000 IU daily, 6,000 IU daily, 8,000 IU daily, and 10,000 IU daily. Masking is listed as none. The study therefore compares assigned dose groups without reported masking, rather than comparing a blinded supplement with a control treatment.
The registry reports enrollment of 148 and lists Roswell Park Cancer Institute as the sponsor. The recorded study start is 2007-06, primary completion is 2011-05, and status is completed. Those record details establish the study’s scope and administrative status; they do not describe how participants were recruited, how randomization was implemented, or how the study was monitored. Those details are not reported in the registry record.
The primary outcome population is described as all treated and eligible patients. That wording does not establish that every enrolled participant contributed measurements at every time point, nor does it identify the number analyzed for each dose and visit. Arm-level numbers at risk are reported for adverse-event outcomes, but these are not interchangeable with the primary-outcome analysis populations. The registry record does not report the sequence-generation method, allocation concealment, adherence to assigned dose, treatment discontinuation, or the handling of participants who had no follow-up measurement.
The listed secondary outcomes concern parathormone response, toxicity, and the occurrence of infections, deep vein thrombosis, vascular events, and falls. The record lists four outcome measures and 24 analyses, but does not provide a full account of how each analysis corresponds to the outcomes and follow-up times. A complete protocol or detailed statistical analysis plan is not reported in the registry record, so the design can be characterized only to the extent described in the entry.
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: Total 148 patients were treated but only 128 patients were eligible for study outcome analysis.
Overall Study
| Stage | Arm I: Vitamin D 4000 IU Daily | Arm II: Vitamin D 6000 IU Daily | Arm III: Vitamin D 8000 IU Daily | Arm IV: Vitamin D 10,000 IU Daily |
|---|---|---|---|---|
| STARTED | 37 | 35 | 36 | 40 |
| COMPLETED | 34 | 34 | 33 | 34 |
| NOT COMPLETED | 3 | 1 | 3 | 6 |
Reasons for not completing this period:
| Reason | Arm I: Vitamin D 4000 IU Daily | Arm II: Vitamin D 6000 IU Daily | Arm III: Vitamin D 8000 IU Daily | Arm IV: Vitamin D 10,000 IU Daily |
|---|---|---|---|---|
| progression | 0 | 0 | 0 | 1 |
| Adverse Event | 2 | 0 | 0 | 1 |
| Other | 0 | 1 | 2 | 3 |
| Withdrawal by Subject | 1 | 0 | 1 | 1 |
Analysis population for the primary outcome, as defined in the registry: All treated and eligible patients
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: All treated and eligible patients
| Characteristic | Unit | Arm I: Vitamin D 4000 IU Daily | Arm II: Vitamin D 6000 IU Daily | Arm III: Vitamin D 8000 IU Daily | Arm IV: Vitamin D 10,000 IU Daily | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 37 | 35 | 36 | 40 | 148 | |
| Age, Continuous | years | 68.2 (SD 8.1) | 65.4 (SD 8.7) | 67.9 (SD 8.7) | 66.4 (SD 9.3) | 66.5 (SD 8.7) |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 37 | 35 | 36 | 40 | 148 |
6. Primary Endpoint
The registry lists the primary outcome as Pattern of Response of Serum 25(OH) D3 Levels, measured over Baseline, at 1, 3, 6 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | ng/mL |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the pattern of response in serum 25(OH) D3 levels. The registry defines the outcome as change from baseline at 1, 3, and 6 months, measured in ng/mL, for the four daily dose levels. It identifies the summary measure as a mean and the dispersion measure as a standard deviation. These choices describe a continuous outcome: each participant’s measurement can take values across a scale, and the group response can be summarized by an average and the spread of observations around that average.
Using change from baseline focuses the analysis on how measurements differ from each participant’s starting value, rather than reporting follow-up concentrations alone. Repeated time points allow the registry’s stated outcome to describe response over follow-up, not just at a single visit. Comparing the pattern across assigned doses is relevant to the study’s stated purpose of examining serum 25(OH) D3 variability in response to different doses. This is a description of the measurement strategy, not evidence that a particular dose produced a larger or more favorable response.
The registry names a one-sample t-test but does not report the tested reference value, the mean changes, standard deviations, confidence intervals, or p-values. A one-sample test generally evaluates a sample mean against a specified reference value; the exact reference and implementation are not reported in the registry record. Without the numerical outcome data and test results, the size and precision of the observed changes cannot be assessed from this entry.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry entry identifies the question and outcome structure, but it does not report numerical results for the primary endpoint. In particular, it gives no mean change in serum 25(OH) D3, standard deviation, confidence interval, or p-value for any dose and follow-up time. The stated outcome is therefore interpretable as a planned measurement and analysis target, but not as a reported estimate of the response. No conclusion about the direction, magnitude, or precision of serum-level changes can be drawn from the information in the registry record.
The design is randomized and parallel, with four daily dose assignments and no masking. These characteristics describe how the study was organized, but do not substitute for outcome estimates. Randomization can support comparisons between assigned groups when the allocation process is implemented appropriately and analyzed as intended; details of the process and the actual group comparisons are not reported in the registry record. The listed primary analysis is a one-sample t-test, not a named direct comparison of each dose with another. The record does not specify the null value tested or show whether dose groups were compared statistically.
Four dose levels and measurements at baseline and follow-up create a response pattern across both dose and time. A reader would need estimates at the relevant visits, the numbers contributing data, and uncertainty around those estimates to judge how clearly the pattern is characterized. Those details are not reported in the registry record. The number of listed analyses does not itself reveal which tests were confirmatory, how repeated measurements were handled, or whether any adjustment was made for multiple testing.
The adverse-event entry reports arm-specific numbers at risk and affected counts. In the 4,000 IU arm, serious adverse events are reported for 2 among 37 at risk; in the 6,000 IU arm, 0 among 35; in the 8,000 IU arm, 1 among 36; and in the 10,000 IU arm, 5 among 40. These counts describe the posted registry data and do not establish that any difference between dose groups is statistically reliable. The registry also lists other adverse-event counts, but provides no comparative analysis or uncertainty estimates for these figures. Death counts are not reported in the registry record.
For the serious-event terms, the record lists Monarthritis and Hospitalisation at 2.8%, and Pancytopenia, Arrhythmia, Gastrointestinal haemorrhage, and Pain at 2.7%. The denominator and calculation details for these percentages are not reported in the registry record, so they should not be treated as directly comparable rates across groups without further information. Overall, the posted results are insufficient to quantify the primary response or establish a dose-response pattern, and the safety figures are descriptive counts rather than a comparative estimate.
9. Statistical Methods Explained
What does a mean and standard deviation describe?
General statistical explanation: A mean describes the central value of a set of measurements. A standard deviation describes how much individual measurements vary around that mean. These summaries answer different questions: the mean concerns the average level or change, while the standard deviation concerns the spread among observations. A mean alone does not show whether participants had similar responses or widely differing responses.
For this trial, the registry identifies the primary outcome as a mean change in serum 25(OH) D3 and names standard deviation as the dispersion measure. These labels tell readers what types of summaries were intended, but the numerical means and standard deviations are not reported in the registry record. Without those values, neither the average response nor its variability can be described from the entry.
How should change from baseline be understood?
General statistical explanation: A change score is calculated by comparing a follow-up measurement with a starting measurement for the same participant. Summarizing these changes can describe whether measurements tended to rise or fall from baseline. A change-score analysis is not identical to comparing follow-up values alone, and the choice of analysis can affect interpretation. The registry states that change from baseline was assessed at 1, 3, and 6 months. It does not report the individual-level data, numerical change estimates, or additional model details needed to assess how the repeated measurements were handled.
The fact that the endpoint is measured at several visits makes the timing of the estimate important. A response at one visit does not by itself describe the response at another. The registry’s use of the phrase pattern of response indicates that outcomes across time are of interest, but no single numerical trajectory or joint analysis is reported in the registry record.
What does a one-sample t-test do?
General statistical explanation: A one-sample t-test evaluates whether a sample mean is compatible with a specified reference value, taking account of the observed variability and the amount of information in the sample. The result is usually interpreted through a test statistic, a p-value, and ideally an estimate with a confidence interval. A p-value alone does not measure the size or practical importance of an effect; an estimate and its uncertainty are needed to understand magnitude and precision.
The registry says that statistical analysis was done using a one-sample t-test. It does not identify the reference value, specify whether tests were run separately for each dose and time point, or report test statistics, p-values, or confidence intervals. It also does not describe a model for direct comparisons among the four dose groups. Therefore, the named test gives limited information about the analysis, and it cannot be used to infer unreported results.
Why does uncertainty matter?
General statistical explanation: A confidence interval gives a range of values compatible with the data and the estimation procedure, under its assumptions. A narrower interval indicates greater precision for the estimate; a wider interval indicates more uncertainty. It is not a guarantee that the true value lies in the interval, and it does not replace judgment about the size or relevance of an estimated change.
No confidence intervals for the primary endpoint are reported in the registry record. As a result, the precision of the mean changes cannot be evaluated. The arm sizes reported for safety outcomes do not supply the missing precision for the continuous primary outcome, because the analysis populations and outcome measurements may differ.
How should planning calculations be distinguished from trial findings?
General statistical explanation: A sample-size calculation is a planning exercise: it asks how much information a future study might need under stated assumptions about an effect, variability, allocation, and a statistical test. It is not an estimate of the probability that the completed study found a true effect. In particular, a calculation based on an observed effect is a planning illustration and should not be described as observed power.
The record describes planning assumptions involving a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as fractions of an observed effect. It distinguishes participant counts per arm from total event counts for time-to-event calculations. These assumptions do not establish that the trial was originally designed using those calculations. The protocol’s own sample-size justification is not reported in the registry record. Because the primary effect estimates needed to interpret such illustrations are not reported in the registry record, the planning assumptions do not fill the gap in the clinical results.
Why can over-dispersion matter?
General statistical explanation: Over-dispersion occurs when observed variation is greater than a statistical model expects. If a model assumes less variability than the data contain, uncertainty may be understated and tests may appear more decisive than warranted. The issue is especially relevant for outcomes that are counts or event rates and for models that rely on a particular variance structure. This trial’s primary endpoint is described as a continuous measure analyzed with a one-sample t-test, and the registry does not report a count model or an over-dispersion analysis. It would therefore be inappropriate to assert that over-dispersion was present or that it affected the trial’s findings.
More broadly, methods should match the outcome, measurement schedule, and research question. The registry record does not report enough analysis detail to determine whether all dependencies among repeated measurements or all differences between dose groups were incorporated. That absence limits statistical interpretation; it is not evidence that any particular method was or was not used beyond the one-sample t-test explicitly named.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome spans four dose levels and follow-up measurements at 1, 3, and 6 months. Considering several dose-and-time results creates a multiplicity question: when many hypotheses are tested, the chance of at least one apparently noteworthy result can rise if each test is interpreted separately. General statistical explanation: Prespecified testing strategies or adjustments can help control the interpretation of multiple comparisons, but the appropriate approach depends on the questions and analysis plan.
The registry lists 24 analyses, but does not explain which analyses belong to the primary outcome, which are secondary or exploratory, or whether any multiplicity procedure was used. No adjustment method, hierarchy of hypotheses, or prespecified primary contrast is reported in the registry record. The one-sample t-test description alone does not resolve these questions.
Missing-data handling is also not reported in the registry record. The primary outcome population is described as all treated and eligible patients, but the entry does not state how many had measurements at each visit or how incomplete follow-up was handled. It does not report whether an analysis used only observed measurements, imputed values, or another method. Nor does it describe sensitivity analyses for missing outcomes. The adverse-event at-risk counts should not be assumed to be the denominators for the primary outcome, since the record does not establish that these populations coincide.
The record also does not report a detailed analysis population definition beyond the phrase all treated and eligible patients. It does not specify whether participants were analyzed according to assigned dose, treatment received, or another rule. The randomized design makes the analysis population especially important for interpreting dose comparisons, but the registry’s brief description does not establish which approach was used. These omissions prevent a full assessment of multiplicity, missing-data bias, and the relationship between randomization and the reported analyses.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Arm I: Vitamin D 4000 IU Daily | 2 | 37 | 5.4% |
| Arm II: Vitamin D 6000 IU Daily | 0 | 35 | 0.0% |
| Arm III: Vitamin D 8000 IU Daily | 1 | 36 | 2.8% |
| Arm IV: Vitamin D 10,000 IU Daily | 5 | 40 | 12.5% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Arm I: Vitamin D 4000 IU Daily | 3 of 37 |
| Arm II: Vitamin D 6000 IU Daily | 3 of 35 |
| Arm III: Vitamin D 8000 IU Daily | 3 of 36 |
| Arm IV: Vitamin D 10,000 IU Daily | 9 of 40 |
Most frequent serious adverse event terms
| Event term | Organ system | Arm I: Vitamin D 4000 IU Daily | Arm II: Vitamin D 6000 IU Daily | Arm III: Vitamin D 8000 IU Daily | Arm IV: Vitamin D 10,000 IU Daily |
|---|---|---|---|---|---|
| Hospitalisation | Surgical and medical procedures | 0 of 37 | 0 of 35 | 1 of 36 | 1 of 40 |
| Pancytopenia | Blood and lymphatic system disorders | 1 of 37 | 0 of 35 | 0 of 36 | 0 of 40 |
| Arrhythmia | Cardiac disorders | 1 of 37 | 0 of 35 | 0 of 36 | 0 of 40 |
| Gastrointestinal haemorrhage | Gastrointestinal disorders | 1 of 37 | 0 of 35 | 0 of 36 | 0 of 40 |
| Chest pain | General disorders | 0 of 37 | 0 of 35 | 0 of 36 | 1 of 40 |
| Pain | General disorders | 1 of 37 | 0 of 35 | 0 of 36 | 0 of 40 |
| Diverticulitis | Infections and infestations | 0 of 37 | 0 of 35 | 0 of 36 | 1 of 40 |
| Pneumonia | Infections and infestations | 1 of 37 | 0 of 35 | 0 of 36 | 0 of 40 |
| Investigation | Investigations | 0 of 37 | 0 of 35 | 0 of 36 | 1 of 40 |
| Monarthritis | Musculoskeletal and connective tissue disorders | 0 of 37 | 0 of 35 | 1 of 36 | 0 of 40 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Arm I: Vitamin D 4000 IU Daily | Arm II: Vitamin D 6000 IU Daily | Arm III: Vitamin D 8000 IU Daily | Arm IV: Vitamin D 10,000 IU Daily |
|---|---|---|---|---|---|
| Aspartate aminotransferase increased | Investigations | 1 of 37 | 1 of 35 | 0 of 36 | 1 of 40 |
| Hypoglycaemia | Metabolism and nutrition disorders | 0 of 37 | 2 of 35 | 0 of 36 | 0 of 40 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 0 of 37 | 0 of 35 | 1 of 36 | 1 of 40 |
| Lymphopenia | Blood and lymphatic system disorders | 0 of 37 | 0 of 35 | 0 of 36 | 1 of 40 |
| Tinnitus | Ear and labyrinth disorders | 0 of 37 | 0 of 35 | 0 of 36 | 1 of 40 |
| Asthenia | General disorders | 0 of 37 | 0 of 35 | 0 of 36 | 1 of 40 |
| Thirst | General disorders | 1 of 37 | 0 of 35 | 0 of 36 | 0 of 40 |
| Herpes zoster | Infections and infestations | 0 of 37 | 0 of 35 | 1 of 36 | 0 of 40 |
| Influenza | Infections and infestations | 0 of 37 | 0 of 35 | 1 of 36 | 0 of 40 |
| Oral fungal infection | Infections and infestations | 0 of 37 | 0 of 35 | 1 of 36 | 0 of 40 |
Serious events with the highest arm-level rate: monarthritis (2.8%), hospitalisation (2.8%), pancytopenia (2.7%), arrhythmia (2.7%), gastrointestinal haemorrhage (2.7%).
The registry reports serious adverse-event counts by arm, alongside the number at risk. For the 4,000 IU daily arm, the serious-event count is 2 among 37 at risk. For the 6,000 IU daily arm, it is 0 among 35; for the 8,000 IU daily arm, 1 among 36; and for the 10,000 IU daily arm, 5 among 40. These are descriptive registry figures. They do not, by themselves, show whether the groups differ beyond what could be expected from sampling variation, and no comparative statistical analysis or confidence intervals for these counts are reported in the registry record.
The registry also lists other adverse-event counts: 3 among 37 at risk in the 4,000 IU arm, 3 among 35 in the 6,000 IU arm, 3 among 36 in the 8,000 IU arm, and 9 among 40 in the 10,000 IU arm. The entry distinguishes these figures from the serious-event counts, but does not provide enough detail to establish the event definitions, duration at risk, or whether people with multiple events are counted once or more than once. These counts should not be added together or treated as mutually exclusive categories.
Listed serious-event terms include Monarthritis and Hospitalisation at 2.8%, and Pancytopenia, Arrhythmia, Gastrointestinal haemorrhage, and Pain at 2.7%. The basis and denominator for these percentages are not reported in the registry record. Death counts are also not reported in the registry record; a blank death entry should not be interpreted as evidence that no deaths occurred.
12. What the Result Does, and Does Not, Mean
The study is described as a randomized phase II comparison of four daily cholecalciferol doses in patients with prostate cancer. Its primary question concerns changes from baseline in serum 25(OH) D3 at 1, 3, and 6 months. The registry record establishes that these measurements and a one-sample t-test were the stated focus, but it does not report the numerical endpoint results. It therefore does not show the size, direction, variability, or precision of changes at any dose or visit.
The record cannot support a conclusion about which dose produced a larger change, whether responses differed across dose levels, or whether the measured changes were statistically distinguishable from a reference value. Those conclusions would require estimates and uncertainty, as well as clear descriptions of the tested contrasts and analysis populations. None of those numerical primary-outcome results are reported in the registry record.
The adverse-event counts are useful as descriptive information about what the registry recorded in each arm. They are not a causal comparison, and the reported counts do not establish that one dose is safer or less safe than another. The entry lacks comparative estimates, uncertainty measures, detailed exposure or follow-up information, and an account of the event ascertainment needed for a fuller safety assessment. The listed serious-event percentages also lack reported denominator details.
More generally, a completed trial record is not necessarily a complete statistical report. Trial status, randomization, and enrollment describe administrative and design features, while an assessment of results needs numerical outcome estimates and methods. In this case, the registry’s description can clarify what was studied, but it cannot establish the efficacy or safety of supplementation, or support medical advice. The absence of results in the registry entry should be treated as an information limitation, not as evidence for or against a treatment effect.
13. Why This Trial Matters Statistically
This trial illustrates why a research question and an outcome definition are not substitutes for reported estimates. The registry specifies a continuous serum measure, a change-from-baseline framework, several follow-up times, and four assigned dose levels. Those details identify the structure of the question. Statistical interpretation still depends on the observed means, their variability, the number of measurements contributing to each estimate, and uncertainty around the results. The numerical primary findings are not reported in the registry record.
The entry also illustrates the distinction between a test and an effect estimate. Naming a one-sample t-test signals a type of statistical procedure, but does not reveal the tested reference value, the resulting p-values, or the magnitude and precision of any change. A test result, even if reported, would not replace an estimate with uncertainty. For multiple dose-and-time results, a reader also needs to know how the analyses were organized and how multiplicity was addressed.
The safety record underscores the same principle. Counts at risk and affected counts are informative descriptions, but raw counts alone do not quantify uncertainty or establish group differences. Definitions, time at risk, analysis populations, and event handling affect how such figures should be understood. The serious-event percentages are listed without denominator details in the registry record.
Finally, planning assumptions should remain separate from findings. Sample-size planning illustrations depend on assumptions and do not represent observed power or prove that the completed study was adequately powered for every question. The registry does not report the trial’s original sample-size justification. This record is therefore useful for identifying design and reporting questions that matter to biostatistical review, while leaving the main quantitative response unanswered.
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 limitation for interpretation is that the primary endpoint is described without its numerical results. The registry record does not report mean changes, standard deviations, confidence intervals, p-values, or the number of patients contributing data at each visit and dose level. As a result, the primary response cannot be quantified or compared across doses from the registry entry.
The analysis description is brief. Although a one-sample t-test is named, the reference value, testing structure, and treatment of repeated measurements are not reported in the registry record. No direct between-dose comparison is specified. The record lists 24 analyses but does not describe their allocation across outcomes or provide a multiplicity plan. It also does not report missing-data procedures, sensitivity analyses, or a detailed definition of the analysis population.
The primary outcome population is described as all treated and eligible patients, but the entry does not report eligibility criteria or the number analyzed at each assessment. It does not describe adherence, discontinuations, or exposure duration. These details matter when interpreting changes over time and understanding whether the measurements represent the randomized groups.
For safety, arm-level counts are reported, but event definitions, ascertainment details, follow-up time at risk, and uncertainty estimates are not reported in the registry record. The denominators behind the listed serious-event percentages are also not given, and death counts are not reported. The record’s completed status does not resolve these reporting gaps. A protocol, full statistical analysis plan, or more complete results report is not described in the registry record, so it is not possible to determine whether omitted details were specified elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Vitamin D in Treating Patients With Prostate Cancer — NCT00524680.
- Registry record last updated 2015-11-02; status last verified 2015-09.
- Results first posted 2015-11-02.
- 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
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry identifies NCT00524680 as a completed, randomized phase II study of daily oral cholecalciferol in patients with prostate cancer. It lists four dose levels—4,000 IU, 6,000 IU, 8,000 IU, and 10,000 IU—and no masking. Enrollment is reported as 148, with Roswell Park Cancer Institute listed as sponsor.
The primary outcome is the pattern of serum 25(OH) D3 response, measured as change from baseline at 1, 3, and 6 months. The outcome is described using a mean and standard deviation, and a one-sample t-test is named. The numerical primary-outcome results and key analysis details are not reported in the registry record. Adverse-event counts are listed by arm, but the record does not provide comparative estimates or uncertainty for those counts. The entry establishes the study’s topic and broad design, while leaving the magnitude and precision of the primary findings unresolved.