Docetaxel, Radiation Therapy, and Prednisone in Treating Patients Who Have Undergone Surgery For Prostate Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Docetaxel, Radiation Therapy, and Prednisone in Treating Patients Who Have Undergone Surgery For Prostate Cancer (NCT00348816), a na phase 2 study. The primary outcome is Rate of Prostate-Specific Antigen (PSA) Decline Reported as the Number of Subjects Reaching a PSA Nadir of Zero Following the Intervention..

2. Clinical Question

3. Trial Design

This was a phase II, single-group study of docetaxel, radiation therapy, and prednisone in patients with prostate cancer after radical prostatectomy and persistent or rising PSA. The registry identifies allocation as not applicable and masking as none. These details are consistent with a study in which the listed participants received the study regimen without a separate randomized control arm. The record reports enrollment of 21 and lists the study status as terminated. It does not report why the study was terminated.

The arm description combines treatment and standard-of-care components. It specifies docetaxel 20mg/m2/week intravenously during radiation treatment for 7 cycles, prednisone 5mg twice a day, radiation therapy, and radical prostatectomy as standard of care. It also mentions docetaxel after radiation, but the schedule and dose for that part are not reported in the registry record. The official title describes concomitant radiation and docetaxel followed by docetaxel chemotherapy. The intervention description does not establish how consistently each component was received.

The record notes treatment deviations in the primary-outcome population description: one subject was non-compliant and taken off study, one did not receive docetaxel #7 during radiation because of a change in performance status, and one received only 1 post-radiation docetaxel. It also says two subjects did not receive something, but does not specify what in that description. The registry lists secondary outcomes concerning PSA-based progression-free survival, overall survival, and the association between subsequent PSA-failure velocity and survival. The statistical analysis plan, eligibility details beyond the stated clinical context, and reasons for termination 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: Subjects must have histologic diagnosis of prostate cancer and be post prostatectomy. They must have a PSA \> 0.2 ng/ml (verified on 2 separate tests, at least 2 weeks apart). CT abdomen/pelvis and bone scan must be negative. One subject was a screen failure due to CT showed lung mass (not related to prostate cancer).

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Exceptions to group description: (1) one subject non-compliant and taken off study (not included in analysis); (2) one subject did not receive docetaxel #7 during radiation due to change in performance status; (3) one subject received only 1 post radiation docetaxel; (4) two subjects did not receive post radiation docetaxel #4.

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: 21 patients were consented, 1 patient was screen failure due to lung mass found during staging.

6. Primary Endpoint

The registry lists the primary outcome as Rate of Prostate-Specific Antigen (PSA) Decline Reported as the Number of Subjects Reaching a PSA Nadir of Zero Following the Intervention., measured over 5 years.

The primary endpoint is the number of participants reaching a PSA nadir of zero after the intervention. PSA is a biomarker monitored after prostate cancer treatment. A nadir is the lowest observed PSA level over the relevant follow-up; in this endpoint, the specified level is zero. The record says participants were monitored for PSA decline for up to 5 years of follow-up, with a stated timeframe of 5 years.

A count of participants reaching a defined threshold is straightforward to describe: it records whether the specified PSA outcome occurred for each participant included in the endpoint analysis. It does not, by itself, describe the timing of a decline, the duration of a response, or the pattern of PSA values among participants who did not reach zero. Those questions require additional measures or analyses. The endpoint is therefore a specific measure of PSA response, rather than a complete summary of clinical course.

The primary endpoint title and description are present, but its observed count and the denominator used for the analysis are not reported in the registry record. The record notes one subject excluded from analysis and several treatment deviations, but it does not fully define the analysis population. Without the outcome count and a clear denominator, the degree of observed PSA response and its precision cannot be assessed from the posted endpoint data.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information in the registry is limited. It identifies the study as phase II and single-group, gives the primary endpoint as a participant count, and lists 0 analyses. A detailed statistical analysis plan is not reported in the registry record. The concepts below explain how the stated endpoint and design are generally interpreted; they do not assert that any particular unreported procedure was used in this trial.

What does a count-based endpoint capture?

In general, a count endpoint records how many participants meet a prespecified outcome definition. For this trial, the definition is reaching a PSA nadir of zero following intervention. To interpret such a count, readers need both the number meeting the definition and the number included in the analysis. The numerator describes participants who met the threshold; the denominator defines the group in which that numerator was assessed. Neither the observed numerator nor the analysis denominator is reported in the registry record. Enrollment alone cannot substitute for the analysis denominator when exclusions or treatment deviations are described.

A count also compresses information. Participants who reach a zero nadir at different times may contribute equally to the count, while participants whose PSA declines but does not reach zero are not counted as having met the endpoint. The endpoint does not itself summarize the amount or timing of PSA change. Other outcomes or analyses would be needed for those questions. The record's stated monitoring period is up to 5 years, but the rules for handling follow-up that ends earlier, missing PSA measurements, or a participant who does not reach the threshold are not reported.

How should precision be understood?

In general, a confidence interval expresses uncertainty around an estimated outcome. For a proportion based on a count, its width depends on the number of participants analyzed and the observed outcome pattern, as well as the interval method. A narrow interval indicates greater statistical precision under the method's assumptions; a wide interval indicates more uncertainty. The registry record does not report a confidence interval, an estimated proportion, or the endpoint count, so precision for the primary outcome cannot be judged from the posted endpoint information.

A p-value, when reported, addresses compatibility between data and a specified statistical model or null hypothesis. It is not a measure of clinical importance, and it does not replace an estimate with its uncertainty. No primary-endpoint p-value or analysis is reported in the registry record. The registry also does not report whether the endpoint was tested against a benchmark or whether any hypothesis test was planned.

What does the single-group design permit?

In general, a single-group study can describe outcomes among participants receiving a regimen. It does not supply a concurrent randomized comparison. Consequently, an outcome observed after treatment cannot, on its own, quantify a causal difference from another treatment or no treatment. Differences in patient characteristics, the natural course of disease, follow-up, and other care can affect comparisons made with groups outside the trial. The registry identifies allocation as not applicable and the model as single group; it does not report a comparator group or an adjusted comparative analysis.

Masking is listed as none. In general, lack of masking can influence subjective assessments or care decisions when those are relevant. A PSA value is a laboratory measurement, but the registry does not describe laboratory procedures, endpoint adjudication, or whether outcome assessors were otherwise kept unaware of treatment or clinical information. No further assumptions about assessment procedures are warranted from the record.

How should planning illustrations be read?

Sample-size calculations are planning tools, not observed results. A planning illustration based on an observed effect does not show that the trial had a particular probability of detecting an effect, and it is not observed power. The registry describes planning assumptions of a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a fraction of the observed effect. Those assumptions describe a hypothetical two-arm planning framework, whereas the trial itself is a single-group study. The registry record does not report the original sample-size justification or establish that this illustration formed part of the study's design.

For time-to-event outcomes, a planning calculation may be based on the total number of events rather than the number of participants per arm. For other outcomes, the record describes planning quantities as participants per arm. Such conventions do not establish that an analysis was conducted or that its assumptions fit the study. The actual planning outputs and their underlying observed effect are not reported in the registry record.

Why can over-dispersion matter?

In general, over-dispersion occurs when variability in count data exceeds what a chosen statistical model expects. If a model assumes less variability than is present, its uncertainty estimates may be too small, making results appear more precise than warranted. The relevant model and any assessment of over-dispersion are not reported in the registry record. The primary endpoint is described as a participant count, but the record does not state that a count regression model was used; the concept should not be mistaken for a description of the trial's analysis.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Docetaxel (Single Arm)")
n      <- c(19)
events <- c(12)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Docetaxel (Single Arm)  19  12  63.2  38.4  83.7  41.0  80.9  40.8  80.9

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 4 outcome measures and identifies a primary PSA endpoint alongside secondary outcomes for PSA-based progression-free survival, overall survival, and the correlation between subsequent PSA-failure velocity and survival. It lists 0 analyses. The registry record does not report which outcomes were analyzed, whether the listed outcomes were all prespecified in the same way, or whether any multiplicity adjustment was planned or performed. When multiple outcomes are examined, general statistical practice recognizes that the chance of at least one apparently unusual result can increase; adjustments or a hierarchy of outcomes may address that issue. No such approach can be attributed to this study from the record.

Missing-data handling is also not reported. The endpoint description says participants were monitored for PSA decline for up to 5 years, but it does not explain how incomplete follow-up, absent PSA measurements, or an unknown nadir were handled. The record notes one non-compliant subject taken off study and excluded from analysis, along with treatment deviations and a statement that two subjects did not receive something unspecified. It does not provide a complete participant flow or define an intention-to-treat, per-protocol, or other analysis population.

These omissions limit interpretation of both the endpoint estimate and its precision. The enrollment count cannot be assumed to be the denominator for every analysis, and the registry does not report enough information to reconstruct an endpoint denominator. The statistical analysis plan, missing-data assumptions, and sensitivity analyses are not reported in the registry record.

12. 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: infection with normal anc or grade 1 or 2 neutrophils (15.0%), stricture/stenosis gu: bladder neck (10.0%), pain - other: cardiac (10.0%), cardiac general - other: (10.0%), cns cerebrovascular ischemia (10.0%).

The adverse-event summary for the Docetaxel (Single Arm) group lists 20 participants at risk for serious adverse events, with 12 affected, and 20 at risk for other adverse events, with 20 affected. It also lists 12 deaths. These are separate entries in the registry's safety summary; the record does not explain participant-level overlap among the categories or establish that deaths were caused by treatment.

The listed serious-event terms include infection with normal ANC or Grade 1 or 2 neutrophils at 15.0%, bladder-neck stricture/stenosis at 10.0%, cardiac pain at 10.0%, other cardiac general events at 10.0%, CNS cerebrovascular ischemia at 10.0%, and mood alteration at 10.0%. The record does not provide event counts for each term, definitions of the percentage denominators, timing, duration, or severity details beyond the terms shown. The terms may overlap within participants and should not be added together.

These figures are descriptive and come from a single-arm study. Without a comparator, they do not estimate an excess risk relative to another treatment. The registry record does not report causality assessments or additional context needed to interpret the deaths or individual event terms.

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

The record establishes that a phase II, single-group study evaluated a regimen involving docetaxel, radiation therapy, and prednisone after radical prostatectomy in patients with persistent or rising PSA. It defines the primary endpoint as the count of participants reaching a PSA nadir of zero, monitored for up to 5 years. It also lists secondary outcomes and adverse-event summaries. Those descriptions identify the questions the study addressed, but they are not themselves outcome results.

The primary endpoint's observed count and analysis denominator are not reported in the registry record. The record also lists 0 analyses and does not provide numerical results for the secondary outcomes. Therefore, the posted information does not establish how often participants reached a zero PSA nadir, how precise any endpoint estimate was, or what the study found for progression-free survival or overall survival. No unreported result can be inferred from the study title, rationale, or treatment description.

Even if a within-group outcome result were available, the single-group design would not provide a randomized estimate against a control arm. It could describe outcomes among participants receiving the regimen, but would not by itself separate the contribution of each treatment component or establish a causal contrast with another approach. The registry's status of terminated is reported, but the reason for termination is not; it should not be interpreted as evidence about efficacy or safety.

The safety entries report affected-participant counts and selected event terms. They do not, on their own, demonstrate that treatment caused an event, nor do they allow comparison with another group. Overall, the record describes the study design, intended outcomes, some treatment deviations, and safety summaries, but it does not report the numerical primary efficacy result or the analysis information needed for a fuller assessment.

14. Why This Trial Matters Statistically

This trial illustrates why an endpoint definition and an endpoint result are different kinds of information. The registry specifies a clinically interpretable PSA threshold—reaching a nadir of zero—and a follow-up period of up to 5 years. But without the observed count and its denominator, readers cannot estimate how frequently that threshold was reached or how uncertain the estimate would be. A clearly named outcome is not a substitute for its numerical result.

The study also highlights the interpretive limits of a single-group design. A group receiving a multi-component regimen can be followed and described, but the absence of a randomized comparator prevents a like-for-like estimate of differences between treatment strategies. This is especially relevant when docetaxel, prednisone, and radiation therapy are combined: an outcome among treated participants cannot identify the contribution of each component by itself.

Reporting participant flow and analysis populations is central to interpreting results. The record gives enrollment of 21 and notes a subject excluded from analysis, multiple treatment deviations, and an incomplete statement about subjects who did not receive something. Without a clearly defined analysis denominator and missing-data rules, even a reported endpoint count would need context.

Finally, the registry lists multiple outcomes and adverse-event summaries but no analysis records. That contrast makes transparent statistical reporting important: readers need the outcome estimates, uncertainty, analysis populations, and methods to distinguish descriptive findings from comparative evidence. The record's omissions leave the trial's primary statistical result unresolved in the registry.

15. 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 interpreting this record is that the primary endpoint result is not reported. Neither the number reaching a PSA nadir of zero nor the analysis denominator appears in the registry record. The absence of those quantities prevents assessment of the observed endpoint and its precision.

The study has a single-group design, with no allocation to a separate control arm. This limits causal interpretation and precludes a randomized comparison with another treatment. The registry does not report an adjustment strategy that could address confounding in an external comparison, and no such method should be assumed.

The treatment description includes deviations and is incomplete about some participants. One non-compliant subject was taken off study and excluded from analysis; one did not receive docetaxel #7 during radiation because of a change in performance status; one received only 1 post-radiation docetaxel; and the description says two subjects did not receive something without specifying what. The endpoint analysis population and missing-data rules are not reported.

The registry reports termination but does not state its reason. It lists 0 analyses and does not report results for the primary or secondary outcomes. The statistical plan, endpoint assessment procedures, and handling of multiple outcomes are also not reported in the registry record. These limitations concern the available record and do not establish why information is absent or why the study ended.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Docetaxel, Radiation Therapy, and Prednisone in Treating Patients Who Have Undergone Surgery For Prostate Cancer — NCT00348816.
• Registry record last updated 2017-12-08; status last verified 2017-04.
• Results first posted 2017-05-15.
• 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.

19. Record Summary

NCT00348816 is a phase II, single-group study of docetaxel, radiation therapy, and prednisone in patients with prostate cancer after radical prostatectomy and persistent or rising PSA. The registry reports enrollment of 21, no masking, and terminated status. The primary endpoint is the number of participants reaching a PSA nadir of zero, monitored for up to 5 years. Its result and analysis denominator are not reported in the registry record.

The record notes treatment deviations and an exclusion from analysis, lists secondary outcomes related to PSA progression, overall survival, and PSA-failure velocity, and reports adverse-event summaries for the single arm. It lists 0 analyses. The reason for termination, detailed statistical plan, missing-data handling, and numerical efficacy results are not reported in the registry record.