MRI- Guided Transurethral Ultrasound Ablation of Localized Prostate Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for MRI- Guided Transurethral Ultrasound Ablation of Localized Prostate Cancer (NCT03996005), a na na study. The primary outcome is Absence of Clinically Significant Cancer (CSC) on Control Biopsy at 1-year Follow-up..

2. Clinical Question

3. Trial Design

This was a completed, single-group study of MRI-guided transurethral ultrasound ablation of prostate tissue in localized prostate cancer. The registry record lists enrollment as 25 and the study status as completed. The listed start date is 2019-09-24, and the primary completion date is 2023-07-25. The phase is not reported in the registry record.

The intervention was a procedure: magnetic resonance imaging-guided transurethral ultrasound ablation of prostate tissue. The record does not describe a separate control arm. Allocation is listed as NA, and masking is listed as none. These features mean the study is not a randomized comparison. The posted safety information is associated with the treated group; it should not be read as a comparison against an untreated or differently treated group.

The primary objective was absence of clinically significant cancer on control biopsy at 1-year follow-up. Secondary objectives included biochemical response; presence of any clinically significant cancer on biopsy at 1- and 2-year follow-up; radical treatment-free survival; adverse events and clinical tolerance; urinary continence; erectile function; and quality of life. These objectives indicate a broad assessment of cancer findings, subsequent treatment, safety, and patient-related outcomes. The registry record does not report results for those objectives in the information available for this analysis.

Only one outcome measure is listed, and no analysis is listed. The record does not report the analysis population, the number with an evaluable 1-year biopsy, or the handling of participants without follow-up data. Nor does it report a statistical analysis plan or details of the biopsy assessment beyond the stated criteria. These omissions limit interpretation of how the planned endpoint was evaluated and how complete the observed follow-up was.

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.

Overall Study

Reasons for not completing this period:

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Absence of Clinically Significant Cancer (CSC) on Control Biopsy at 1-year Follow-up., measured over 1 year.

The primary endpoint is absence of clinically significant cancer on a control biopsy at 1-year follow-up. It is recorded as a count of participants. The registry defines clinically significant cancer as meeting at least one of the specified biopsy criteria: Gleason score ≥ 7, cancer core length > 3 mm regardless of Gleason score, or > 2 positive cores. Thus, the endpoint focuses on whether the biopsy shows cancer meeting the record's threshold for clinical significance, rather than on a general measure of all cancer findings.

A biopsy endpoint provides a tissue-based assessment at a stated follow-up time. That makes the result distinct from biochemical response, symptoms, or quality-of-life measures, which are listed separately as secondary objectives. The endpoint's interpretation depends on the biopsy being performed and assessed according to the stated criteria. Details such as the biopsy procedure, pathology review, and handling of missing biopsy results are not reported in the registry record.

The endpoint is clinically relevant to the study's stated objective of evaluating cancer control after the procedure. However, the endpoint description alone is not an outcome result. The registry record does not report the number of participants with absence of clinically significant cancer, the number with clinically significant cancer, or an estimate of uncertainty for this endpoint. Without those results, the record identifies what was intended to be measured but does not establish the observed frequency of the primary outcome.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins with the design. This study is listed as single-group, and no concurrent comparator is described. A single-group analysis can summarize outcomes among treated participants, but it cannot make a direct randomized comparison with another treatment. The registry's allocation entry is NA, and the listed masking is none. The record does not report a statistical analysis plan, so the intended methods for estimating the primary endpoint or handling possible sources of bias are unknown.

What does the primary endpoint count?

The primary measure is a count of participants with absence of clinically significant cancer on control biopsy at 1-year follow-up. The definition of clinically significant cancer is based on biopsy findings: Gleason score ≥ 7, cancer core length > 3 mm regardless of Gleason score, or > 2 positive cores. Because the endpoint is framed as absence of clinically significant cancer, interpreting a count would require knowing which participants had an evaluable biopsy and how the criteria were applied. The registry record does not report the observed count, the denominator used for the analysis, or biopsy completion.

For a binary outcome, the underlying information is whether a participant meets the endpoint definition or does not. A count can be informative, but a count without its analysis denominator is hard to interpret as a frequency. A proportion would ordinarily relate the count meeting the definition to the number evaluated under the analysis approach. No such proportion is reported, and no new one can be derived from the enrollment figure alone. Enrollment and endpoint evaluation are not necessarily interchangeable because the record does not state how many participants contributed an observed biopsy result.

What would an uncertainty interval mean?

In general, a confidence interval describes the range of parameter values reasonably compatible with the observed data under a specified statistical method. It communicates precision as well as the direction and size of an estimate. A narrow interval generally reflects more precise information than a wide interval, while neither an interval nor a point estimate resolves limitations in design or data collection. No primary endpoint estimate or confidence interval is reported in the registry record, so precision for the biopsy outcome cannot be assessed.

In general, binary outcomes may be analyzed using methods suited to counts or proportions. The choice can depend on the analysis population, the number of observed events, and whether observations are independent. The registry record does not identify a method for the primary endpoint, report an analysis population, or provide an analysis result. It therefore does not support a claim about which method the sponsor used. No recalculated result is available from the posted summary information.

How should the design affect interpretation?

A single-group study describes outcomes in the group receiving the procedure. Without a comparator, it does not separate the effect associated with the procedure from other influences on outcome. A randomized comparison, when present, can support a different kind of inference because treatment assignment creates a basis for comparing groups; that is not the design recorded. The lack of a control group does not make descriptive counts meaningless, but it limits causal and comparative conclusions.

The record's planning illustration is explicitly based on an observed effect and describes assumptions of two-sided significance level 0.05, equal allocation between two arms, and a normal approximation. It states that the effect to detect is a stated fraction of the observed effect. Those are planning assumptions, not the study's own design or an observed-power result. They do not correspond to the listed single-group design with no comparator. The record does not report a trial-specific sample-size justification. Planning sample sizes should not be read as evidence that the completed study had a particular probability of detecting an effect.

What does over-dispersion mean in general?

For count outcomes, over-dispersion means that observed variability is greater than a chosen model would expect. If a model assumes less variability than is present, its uncertainty estimates can be too optimistic. This is a general statistical consideration, not a reported feature of this study. The primary endpoint is listed as a participant count, and the registry record does not report a model, dispersion estimate, or analysis that would allow assessment of over-dispersion. It would not be appropriate to assert that over-dispersion occurred.

The safety information is also count-based. The record reports participants at risk and participants affected for serious and other adverse events, as well as a death count and selected serious-event terms. These are descriptive registry figures. They do not establish an exposure-adjusted rate, a time-to-event estimate, or a treatment comparison; such analyses are not reported. In general, rates may require person-time or other exposure information, while a time-to-event analysis requires event timing and censoring information. Those details are not reported in the registry record.

Finally, statistical methods cannot compensate for absent outcome reporting. The endpoint definition, study design, and listed safety counts provide useful context, but the primary count, denominator, uncertainty interval, and analysis method are not reported. Without those elements, the central efficacy question remains unanswered by the posted results.

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("MRI Guided Transurethral Ultrasound")
n      <- c(23)
events <- c(8)
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  MRI Guided Transurethral Ultrasound  23  8  34.8  16.4  57.3  18.8  55.1  18.8  55.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary objective and several secondary objectives, including biochemical response; biopsy findings at 1- and 2-year follow-up; radical treatment-free survival; adverse events and clinical tolerance; urinary continence; erectile function; and quality of life. When a study examines multiple outcomes or time points, multiplicity can arise: the more questions assessed, the greater the chance that some findings appear notable by chance alone. In general, approaches to multiplicity may prioritize a primary endpoint, adjust inference across a family of tests, or treat secondary analyses as exploratory. Which approach was intended for this study is not reported in the registry record.

The record lists one outcome measure and no analyses. It does not report whether additional outcomes were collected, whether they were analyzed, or how their results were selected for posting. No multiplicity adjustment, testing hierarchy, or prespecified interpretation of secondary outcomes is reported. Accordingly, no claim about control of multiplicity can be made.

Missing data are also important for a biopsy endpoint at a fixed follow-up. Participants may have a result, may not complete the assessment, or may have a result that cannot be classified; the registry record does not say how these situations were handled. It does not report the number completing the control biopsy, reasons for missing follow-up, an imputation method, or a sensitivity analysis. The number enrolled cannot be assumed to be the endpoint denominator.

The analysis population is not reported in the registry record. It is therefore unclear whether the planned analysis was based on everyone enrolled, participants who received the procedure, participants with a follow-up biopsy, or another defined group. These details affect both the meaning of the endpoint count and the interpretation of any estimated frequency. The posted record does not provide enough information to determine whether missingness or analysis-population choices could have influenced the results.

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

Serious events with the highest arm-level rate: renal failure (4.0%), urinary retention (4.0%), coronary artery disease (4.0%).

The registry lists 25 participants at risk for serious adverse events and 3 participants affected. For other adverse events, it lists 25 at risk and 0 affected. The death count is 1. These are descriptive figures from the treated group, not comparisons with a control group. The record also lists renal failure, urinary retention, and coronary artery disease among the top serious adverse event terms, each reported as 4.0%.

The figures should not be treated as a complete account of safety without the accompanying definitions and context. The registry record does not report event timing, duration, severity grading beyond the serious-event category, attribution to the procedure, or the details needed to understand whether the listed terms occurred in the same or different participants. The relation between the listed terms and the overall count of participants with serious adverse events is not described in the information. The death count is not accompanied by a reported cause or attribution.

In general, adverse-event counts describe what was recorded during a study; they do not alone establish causation. A single-group record also does not estimate how these counts compare with another treatment or background risk. The listed figures can be reported as they stand, but they do not support a comparative safety conclusion or a broader estimate of risk.

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

The registry record describes a completed study of MRI-guided transurethral ultrasound ablation in localized prostate cancer and specifies a biopsy-based primary endpoint at 1-year follow-up. It also records several secondary objectives and selected adverse-event counts. These details show what the study set out to assess and provide a limited descriptive account of safety reporting.

The record does not report the primary biopsy outcome count, an analysis estimate, or a measure of uncertainty. It therefore does not show how many participants had absence of clinically significant cancer, how many had clinically significant cancer, or how precise any estimate might be. The study's completed status is not itself a result. Nor can the enrollment figure be substituted for the number with a completed, evaluable biopsy.

The single-group design also shapes what the evidence could establish. A result from the treated group could describe the outcomes observed in that group, but without a concurrent comparator it would not directly show how outcomes differed from another treatment or control condition. The record does not provide a randomized comparison, and its posted information does not support a causal treatment contrast.

The safety counts indicate that the registry recorded serious adverse events in 3 participants, other adverse events in 0 participants, and 1 death. These figures do not establish whether an event was caused by the procedure, how events unfolded over time, or how safety compares with an alternative. The record's listed serious-event terms add detail but do not replace a fuller account of event definitions and context.

The most defensible interpretation is consequently limited to the study design, endpoint definition, and reported safety counts. The primary result and the methods needed to assess its completeness and precision are not reported in the registry record. Neither a favorable nor an unfavorable efficacy conclusion follows from the absence of that result.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of the gap between a clearly stated clinical question and an interpretable posted result. The registry specifies a clinically focused biopsy endpoint, gives criteria for clinically significant cancer, and identifies a follow-up time. Those details make the intended outcome understandable. But without the endpoint count, denominator, and analysis estimate, readers cannot assess the observed biopsy outcome or its precision.

The single-group design is equally important. Descriptive results can characterize what happened among participants treated in the study, but a comparison with another approach requires a suitable comparator. The registry does not list one. This distinction helps prevent a within-group outcome from being mistaken for evidence of a comparative treatment effect.

The record also illustrates why endpoint definitions and follow-up completeness matter together. A biopsy-based endpoint depends on an observed and classifiable biopsy, yet the number completing the assessment and the handling of missing results are not reported. A clear endpoint definition cannot answer questions about who contributed data or how missing observations were treated.

Finally, the safety counts need careful framing. They document events recorded in the registry, but do not provide a comparison or the detailed context needed to assess timing and attribution. Statistical interpretation is not only about calculating estimates; it is also about matching claims to the design, available data, and reporting. Here, the record supports a description of the study and its stated outcome framework, while leaving the principal efficacy result unresolved.

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.

Several limitations specific to this study affect interpretation. The registry describes a single-group design and no concurrent comparator. This prevents a direct estimate of how outcomes differ from another treatment or control condition. The record lists no masking, so outcome assessment was not masked according to the registry entry; details of biopsy assessment and pathology review are not reported.

The primary endpoint is a control-biopsy outcome at 1-year follow-up, but the record does not report its observed count, denominator, estimate, or uncertainty interval. It also does not report how many participants completed the biopsy or how missing or unclassifiable results were handled. These gaps prevent assessment of the primary outcome's frequency and precision.

Enrollment is listed as 25, while the analysis population is not reported. The record does not describe participant eligibility characteristics beyond localized prostate cancer, procedural delivery, or follow-up completeness. The sample-size justification and statistical analysis plan are not reported in the registry record. Although the record describes a planning illustration with two-arm assumptions, those assumptions do not describe the listed single-group study and should not be interpreted as observed power.

The registry lists safety counts but does not provide event timing, attribution, duration, or a detailed account of the death. The secondary objectives are identified, but their results and the approach to multiplicity are not reported. Together, these omissions restrict interpretation to the recorded design, endpoint definition, and descriptive safety figures; they do not permit a complete appraisal of efficacy, safety, or precision.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: MRI- Guided Transurethral Ultrasound Ablation of Localized Prostate Cancer — NCT03996005.
• Registry record last updated 2026-01-08; status last verified 2025-12.
• Results first posted 2026-01-08.
• 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

The record describes a completed, single-group study of MRI-guided transurethral ultrasound ablation of prostate tissue for localized prostate cancer. Enrollment is listed as 25. The primary objective was absence of clinically significant cancer on control biopsy at 1-year follow-up, using the stated biopsy criteria. Several secondary objectives addressed cancer findings, biochemical response, subsequent treatment, adverse events, function, and quality of life.

No primary outcome count, analysis estimate, or uncertainty interval is reported. The analysis population, missing-data handling, and statistical analysis plan are not reported in the registry record. Safety entries list 3 participants with serious adverse events, 0 with other adverse events, and 1 death, with selected serious-event terms. With no concurrent comparator and no posted primary result, the record supports a description of the study and its stated aims, but not a comparative efficacy conclusion.