MRI Guided Transrectal Prostate Laser Ablation for Benign Prostatic Hypertrophy (BPH): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for MRI Guided Transrectal Prostate Laser Ablation for Benign Prostatic Hypertrophy (BPH) (NCT03131544), a na na study. The primary outcome is International Prostate Symptom Score (IPSS) Change.

2. Clinical Question

In statistical terms, the study was intended to describe change over time in symptoms among people receiving the procedure. Without a control group, any observed change would not by itself distinguish a treatment effect from changes that might occur over time, measurement variation, expectations, or other influences. The registry record gives an anticipated enrollment of 10 men and states that enrollment would be consecutive among people who elected the treatment and chose to participate. That approach describes who could enter the study, but it does not establish that participants represent all people with BPH or all people considering treatment.

3. Trial Design

The registry record describes a prospective, single-center, single-arm study of MRI-guided transrectal laser ablation for benign prostatic hypertrophy. Its allocation is recorded as NA, its masking as none, and its model as single group. The study is marked completed, with enrollment of 10. The record lists the intervention as a device and names the active-treatment arm “FLA for BPH Active Treatment.” There is no control arm or randomized allocation.

The study start date is 2017-04-17, and the primary completion date is 2018-10-15. The registry lists the phase as NA. These design features describe the registry classification and conduct; they do not establish that a particular protocol or analysis plan was followed. Further details about the study setting, eligibility criteria, intervention delivery, follow-up schedule beyond the primary endpoint, or adherence are not reported in the registry record.

The registry summary says participants who elected the treatment and chose to take part would be enrolled consecutively. Consecutive enrollment can describe a recruitment approach, but without further information it does not show how representative the enrolled group was. The single-group design is suited to describing outcomes observed after treatment, but it does not create a contemporaneous counterfactual: there is no separate group showing what would have happened over the same period without the intervention or with another treatment.

The record lists 17 outcome measures and 0 analyses. That distinction matters: a count of registered outcomes is not evidence that results for each outcome were posted, and a lack of listed analyses does not reveal which statistical methods were used in practice. The primary outcome is specified as mean change in IPSS from baseline to 2 months, with standard deviation as the dispersion measure. The numerical result for that endpoint is 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.

Overall Study

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 International Prostate Symptom Score (IPSS) Change, measured over From baseline to 2 months.

The primary endpoint is change in the International Prostate Symptom Score (IPSS) from baseline to 2 months. IPSS is a symptom questionnaire for lower urinary tract symptoms. The registry describes its scale as ranging from 0, meaning none, to 35, meaning severe. A change score represents the difference between a participant’s recorded symptom score at follow-up and that participant’s baseline score; the registry identifies the endpoint as a mean change across the study group.

Using a symptom score as an endpoint allows investigators to summarize patient-reported symptom severity rather than relying only on a procedural or imaging measure. Repeated measurement can describe whether scores changed during follow-up. The standard deviation is intended to describe how dispersed individual changes are around the group mean. It is not a measure of uncertainty in the mean; that uncertainty would ordinarily be conveyed with a confidence interval or another inferential measure.

The registry record does not report the mean change, its standard deviation, the number of participants contributing to the endpoint, or a confidence interval. It therefore does not show the direction, magnitude, or precision of the primary outcome. The scale’s boundaries alone cannot establish how participants’ scores changed, and the endpoint definition should not be mistaken for an observed result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean change describe?

A mean change summarizes the average within-participant difference between a baseline measurement and a later measurement. For this study, the stated interval is from baseline to 2 months, and the measure is IPSS. A group mean can give a concise account of the direction and average size of change, but it can conceal variation: participants may have changes that differ in size or direction. The standard deviation describes the spread of individual changes around their mean. It does not, on its own, show how precisely the mean is estimated.

The registry names mean and standard deviation as the primary endpoint’s summary measures, but it does not post their values. The record therefore permits explanation of the intended summary, not interpretation of an observed estimate. A change-score convention also matters: whether decreases or increases represent improvement depends on how the change is calculated and labeled. The registry identifies the measure as change but does not state the sign convention. No direction should be inferred.

What would a confidence interval add?

In general, a confidence interval expresses uncertainty around an estimate under a specified statistical procedure. A narrower interval indicates greater precision under that procedure, while a wider interval indicates less precision. It is not a guarantee that the true value lies within a particular interval, and its interpretation depends on the assumptions and analysis used. The registry record does not report a confidence interval for mean IPSS change, so the precision of the primary estimate cannot be assessed from the posted results.

A p-value, if reported, would address compatibility between data and a specified null hypothesis under an analysis model. It would not measure the size or clinical importance of a change, and it would not repair the absence of a control group. No p-value or inferential result for the primary endpoint is reported. The record also does not state a null hypothesis or a statistical test for that endpoint.

Why does the single-group design matter?

In a randomized comparison, allocation can support an estimate of the contrast between assigned groups, subject to implementation and analysis assumptions. This study has no randomized comparator. A baseline-to-follow-up comparison instead describes change within the treated group. Such a comparison can be useful for describing observed experience, but it cannot by itself separate treatment-associated change from other time-related or measurement-related influences. This is a general design principle and does not establish that any particular influence affected this study.

The record states that allocation was NA, masking was none, and the model was single group. These labels do not provide further detail about how outcome measurements were collected or whether assessors were involved. The registry does not report an analysis plan or enough information to assess deviations from the intended design.

What do dispersion and over-dispersion mean?

For a continuous outcome such as IPSS change, standard deviation describes variability among individual measurements or changes. It is distinct from the standard error, which describes uncertainty in an estimated mean, and from a confidence interval, which is an interval estimate. The registry specifies standard deviation but does not post its value for the primary endpoint.

Over-dispersion is a general concern in models for count data when observed variability exceeds what a model assumes. It can make standard errors and inferential conclusions unreliable if not addressed. The primary endpoint in this record is a continuous mean change, not a count outcome, so over-dispersion is not the defining issue for the stated primary analysis. The registry does not report models for other outcomes, and no particular model or adjustment should be assumed.

What do the planning assumptions mean?

The registry describes sample-size planning illustrations using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It further describes the target effect as a stated fraction of an observed effect. These are planning assumptions for a hypothetical two-arm calculation; they are not evidence that the trial itself used two arms or that its sample size was selected by this approach. The actual trial is recorded as single-group, with enrollment of 10.

In general, a planning calculation asks how much information might be needed to detect a prespecified effect under assumptions about variability, allocation, and statistical error. Its output is not the same as observed power. Power is a design concept based on assumptions before observing results; calculating it from an observed effect does not provide a valid substitute for an estimate and its uncertainty. The record does not report a protocol sample-size justification, and no numerical sample-size illustration result is included in the registry entries.

Because the primary outcome estimate is not posted, there is no observed effect from this record to interpret, and no precision estimate with which to judge the evidence. General statistical concepts explain what a complete report might convey, but they cannot supply missing trial results.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Focal Laser Ablation (FLA) for BPH Active Treatmen")
n   <- c(10)
m   <- c(-17.5)
sp  <- c(4.3)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Focal Laser Ablation (FLA) for BPH Active Treatmen  10  -17.500  4.300  -20.576  -14.424

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 17 outcome measures. When a study examines multiple outcomes or performs multiple statistical tests, the chance of at least one apparently notable finding can increase if all tests are treated as independent opportunities for discovery. Statistical approaches to multiplicity can include prespecifying a primary outcome, adjusting inference, or clearly distinguishing confirmatory from exploratory analyses. Which approach is appropriate depends on the study’s aims and analysis plan.

The record identifies IPSS change from baseline to 2 months as the primary endpoint, but it does not report a multiplicity strategy or a statistical analysis plan. It also lists 0 analyses. That count does not demonstrate that no analyses were performed; it means the registry record does not list analyses in the information available. No adjustment, hierarchy, or confirmatory status for the remaining outcomes should be inferred.

Missing-data reporting is also limited. The record does not state how many participants contributed to the primary outcome, whether any follow-up measurements were missing, why values might be missing, or whether an imputation or other missing-data method was used. It does not describe whether analyses included all enrolled participants or a defined subset. The analysis populations are therefore not reported in the registry record.

These omissions matter because estimates based on available measurements may differ from estimates under other assumptions about missing observations. The possible direction or size of any such difference cannot be determined without information about missingness and the analysis. No claim about completeness, imputation, exclusions, or sensitivity analyses is supported by 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 0% reporting threshold.

Most frequent non-serious adverse event terms

The safety record lists 0 participants with serious adverse events among 10 at risk. It separately lists 4 participants with other adverse events among 10 at risk. Deaths are recorded as 0. These counts describe the registry’s reported categories and denominators; they should not be converted into broader claims about the procedure’s safety.

The record does not list top serious adverse event terms. It does not provide descriptions of the other adverse events, their severity, timing, duration, relationship to the intervention, or how they were collected. The serious-event and other-event categories should not be assumed to be mutually exclusive: the record does not say whether the participants counted in one category also appear in the other. The figures are counts of affected participants as recorded, not a full accounting of every event episode.

A zero serious-event count in a study of this size means that no serious adverse events were recorded among the participants at risk in this registry entry. It does not prove that the risk is absent, nor does it precisely characterize uncommon events. Likewise, the other adverse event count does not reveal the nature or clinical importance of those events. The safety information is limited to the registry counts and should be interpreted alongside the lack of detail about event definitions and ascertainment.

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

The registry record establishes that a prospective, single-center, single-group study of MRI-guided transrectal laser ablation was completed, with enrollment of 10. It identifies mean IPSS change from baseline to 2 months as the primary endpoint and describes the scale used. It also records serious and other adverse event counts. These are useful details about the study’s design and the outcomes it intended to assess.

The record does not report the primary mean change, its standard deviation, or an inferential estimate. It therefore does not show whether symptom scores changed, how large any change was, or how precise an estimate might be. The endpoint description is not an outcome result. The safety counts likewise do not provide event descriptions or enough information to characterize the full safety profile.

Even if a within-group change estimate were available, the absence of a comparator would limit causal interpretation. A before-and-after difference can describe what was observed among participants, but cannot alone determine what would have occurred over the same period without the procedure or under another treatment. The registry record does not allow that missing comparison to be reconstructed.

The results should not be generalized beyond the recorded study population without considering recruitment, eligibility, follow-up, and analysis details, many of which are not reported. The registry says enrollment was anticipated to be consecutive among men who elected treatment and chose to participate, but this does not establish representativeness. Nor does the completed status itself indicate that the primary analysis was posted.

In short, the record conveys the study question and design but does not provide the primary result needed to assess the observed symptom change. It supports neither a claim of benefit nor a claim of no benefit. The appropriate interpretation is that key outcome and analysis information is not reported in the registry record.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of the distinction between a clearly named endpoint and a reportable result. The registry specifies mean IPSS change from baseline to 2 months and names standard deviation as the dispersion measure. Yet without the estimate and its variability, readers cannot judge the direction, magnitude, or precision of the primary outcome. A well-defined measurement question is necessary for interpretation, but it is not a substitute for outcome data.

The single-group design also makes the target of inference important. Within-group change describes the participants’ observed course; a comparison between groups would address a different question. Since no comparator group is recorded, causal interpretation is constrained even if a change estimate were available. This distinction helps prevent treating temporal association as a treatment contrast.

The entry also illustrates why registry completeness matters for statistical appraisal. The record lists 17 outcome measures and 0 analyses, but does not report a statistical analysis plan, missing-data handling, analysis populations, or multiplicity strategy. These details help readers understand which findings were planned, how uncertainty was quantified, and how the analysis relates to the registered questions.

Finally, safety counts need context. The serious-event count is 0 among 10 at risk, while the other-event count is 4 among 10 at risk. Without event terms and collection details, these counts cannot convey the nature or broader frequency of risks. The study’s small enrollment and lack of a comparator reinforce the descriptive nature of the available safety information. Statistical interpretation depends not only on calculations, but also on design, reporting, and the boundaries of what the data can support.

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 the primary endpoint is that its numerical result is not reported in the registry record. Mean change, standard deviation, participant count contributing to the endpoint, and confidence interval are all absent. Without these, the observed symptom change and its precision cannot be assessed.

The study is single-arm and has no control group. Any within-group change would not by itself distinguish an intervention effect from other explanations for change over time. The record also states that masking was none, but does not give further details about outcome collection or assessment. The implications of that design feature cannot be evaluated more specifically from the registry information.

Enrollment was 10, and the summary describes consecutive enrollment of men who elected the treatment and chose to participate. The record does not provide enough information to assess how closely the enrolled participants reflect a broader population with BPH. Eligibility criteria and participant characteristics beyond the listed conditions are not reported.

Important analysis details are unavailable: the statistical analysis plan, handling of missing measurements, analysis populations, multiplicity approach, and methods used for outcomes other than the named primary endpoint are not reported in the registry record. Although 17 outcome measures are listed, the record gives 0 analyses. The safety record also lacks event terms and detail on ascertainment, severity, timing, and attribution. These limitations restrict both efficacy and safety interpretation and make it difficult to assess the completeness or robustness of the posted results.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: MRI Guided Transrectal Prostate Laser Ablation for Benign Prostatic Hypertrophy (BPH) — NCT03131544.
• Registry record last updated 2024-04-25; status last verified 2024-04.
• Results first posted 2024-04-25.
• 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 registry record describes a completed, prospective, single-center, single-group study of MRI-guided transrectal laser ablation for benign prostatic hypertrophy. It lists enrollment of 10, no masking, and no comparator group. The intervention is described as a 980 nm laser procedure intended to necrotize prostate soft tissue under MRI guidance.

The primary endpoint is mean IPSS change from baseline to 2 months, with standard deviation specified as the dispersion measure. The registry describes IPSS as a symptom scale from 0 (none) to 35 (severe), but does not report the primary outcome estimate or its variability. It lists 17 outcome measures and 0 analyses.

The safety entry records 0 serious adverse events among 10 at risk, 4 other adverse events among 10 at risk, and 0 deaths. Serious event terms are not listed. Missing-data methods, analysis populations, and a statistical analysis plan are not reported in the registry record. The available information therefore describes the study design and selected counts but does not permit assessment of the primary outcome’s magnitude or precision.