Comparative Analysis of Transperineal Versus Transrectal Approaches for MRI-Targeted Biopsy of the Prostate for the Detection and Characterization of Prostate Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparative Analysis of Transperineal Versus Transrectal Approaches for MRI-Targeted Biopsy of the Prostate for the Detection and Characterization of Prostate Cancer (NCT03366792), a na na study. The primary outcome is Core Cancer Length.

2. Clinical Question

The study’s stated purpose was to investigate whether a transperineal biopsy approach, using MRI targeting, could facilitate access to the whole prostate gland and provide limited risk of infectious complications after biopsy. That purpose describes the motivation for studying the procedure, not a result. The record also lists a secondary outcome concerning the percentage of high-grade prostate cancer using Gleason Score, but does not report its result. These endpoint descriptions identify the questions the study intended to examine; they do not establish that the available record contains enough information to answer them.

3. Trial Design

The registry classifies this study as single-group, with allocation listed as not applicable and masking listed as none. Its single arm is named MRI Targeted Biopsy. The intervention is the Artemis™ software system, categorized as a device. These design details do not describe a randomized comparison between separate transperineal and transrectal groups. Although the primary outcome description refers to TP, TR, and TP+TR core cancer length, the design information does not say how those measurements were obtained or compared.

The record lists enrollment as 46 and the study status as terminated. It gives a start date of 2017-10-17 and a primary completion date of 2021-02-26. The reason for termination is not reported in the registry record. The record lists prostate cancer as the condition under study. The brief summary describes an investigation of transperineal MRI-targeted biopsy and its intended access to the prostate gland and limited risk of infectious complications; this is a statement of purpose, not an outcome finding.

The primary outcome is core cancer length, measured in millimeters, with the median and inter-quartile range specified at 2 Months. The description says that results are reported for TP, TR, and TP+TR. A secondary outcome is the percentage of high-grade prostate cancer using Gleason Score. The record lists two outcome measures, but no numerical results for either outcome and no analyses. It does not describe the analysis population, the handling of missing measurements, or a statistical analysis plan. Those details are not reported in the registry record and cannot be inferred from the single-group classification or the outcome wording.

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 Core Cancer Length, measured over 2 Months.

The primary endpoint is core cancer length in millimeters. The record specifies that it is summarized using a median and inter-quartile range at 2 Months. Its description states that greater tumor length per core provides better diagnostic information. That rationale explains why the measure was selected; it does not itself show that any approach produces longer cores or better diagnostic information in this study.

The median is a measure of the center of a distribution: it identifies the middle value when observations are ordered. The inter-quartile range describes the spread of the middle portion of the observations. These summaries can be useful when measurements are not well represented by a mean and standard deviation, or when the distribution is skewed. That is a general statistical explanation, not a claim about the distribution of core cancer length in this study. The registry record does not report the median, the inter-quartile range, the number of cores contributing to each summary, or any uncertainty interval.

The outcome description names three sets of measurements: TP, TR, and TP+TR. It does not explain how the combined measure was constructed, whether observations were paired within participants, or whether the values represent cores, participants, or another analysis unit. Those distinctions matter when interpreting a comparison: multiple cores from one person are not necessarily independent observations. The record does not report an analysis that accounts for any such dependence. Without the numerical endpoint results and analysis details, the endpoint definition can be described, but its observed values and comparative meaning cannot be assessed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the primary endpoint using a median and inter-quartile range. These are descriptive summaries. A median locates the center of ordered observations, while the inter-quartile range describes the spread of the middle half of observations. They provide information about a distribution, but they do not by themselves quantify uncertainty about a treatment contrast. An inferential comparison would ordinarily require a clearly defined estimand, an analysis method, and enough information to assess uncertainty. The registry record does not report these for core cancer length.

Because the endpoint uses a median, an analysis focused on means would not necessarily address the same question. Statistical methods should correspond to the outcome’s scale and the scientific question. For example, a comparison may target a difference in typical values or may compare the full distributions; these are distinct targets. This is a general distinction, not a description of an analysis performed in this study. No test, model, confidence interval, or effect estimate is reported in the registry record.

A confidence interval, in general, expresses the uncertainty of an estimate under a specified statistical method and its assumptions. It is not a guarantee that the true value lies within the interval, and its interpretation depends on the analysis design. Here, no confidence interval for core cancer length or a TP-versus-TR contrast is reported. Without one, the precision of a comparative estimate cannot be evaluated. The absence of a reported interval is not evidence that the difference is precisely zero, nor is it evidence that a clinically meaningful difference exists.

The study is classified as single-group. The outcome description nevertheless names TP, TR, and TP+TR values. A within-participant comparison, if that was the intended structure, would call for methods that account for the relationship between measurements from the same participant. A comparison of independent groups would call for a different analysis structure. Repeated cores from a participant may also be correlated; treating every core as independent can make uncertainty appear smaller than it is. These are general considerations. The registry record does not identify the data structure or report a method addressing dependence.

The median and inter-quartile range can also conceal important features of the data. Distributions with the same median and inter-quartile range can differ in their tails, clustering, or number of zero measurements. A complete interpretation may therefore benefit from graphical and numerical descriptions beyond those two summaries. This is a general point about descriptive statistics, not a claim that such features occurred. The registry record does not report the underlying distribution or participant-level measurements.

The record lists two outcome measures and zero analyses. It does not report which analysis was considered primary for inference beyond naming core cancer length as the primary outcome, whether the secondary outcome was tested, or whether any adjustment for multiple testing was planned. When several outcomes or contrasts are examined, the chance of at least one apparently unusual result can increase if each is interpreted without regard to multiplicity. Whether or how that concern was handled is not reported in the registry record. No p-values are available to interpret.

The record’s sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is framed as a stated fraction of the observed effect. For time-to-event tables, the description refers to total events, while other illustrations are described as participants per arm. Such quantities are hypothetical planning illustrations, not observed power and not evidence about the original study’s design. The record does not report the original sample-size justification. In particular, a hypothetical two-arm planning framework does not change the study’s single-group classification or establish that its participants were allocated to two arms.

Over-dispersion is a general statistical issue that can arise when variability in observed data exceeds what a model assumes. If a method ignores over-dispersion, standard errors and confidence intervals may be too small, and tests may be too optimistic. Whether over-dispersion is relevant depends on the outcome and model. The registry record does not report a model for the primary endpoint, so it cannot be determined whether over-dispersion was assessed or addressed.

For the secondary percentage outcome, interpretation would depend on the numerator, denominator, and method used to account for the way participants and measurements entered the analysis. The record names a percentage of high-grade prostate cancer using Gleason Score but does not report the count, denominator, interval estimate, or model. Therefore, no rate or comparative uncertainty can be reconstructed from the registry information. More generally, descriptive summaries and analysis methods are not interchangeable: a reported measure tells readers what was summarized, while the analysis plan explains how estimates and uncertainty were derived. The latter is not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures: the primary outcome of core cancer length and the secondary outcome concerning the percentage of high-grade prostate cancer using Gleason Score. It does not report an analysis for either outcome. A plan for controlling multiplicity, such as a prespecified hierarchy or adjustment across tests, is not reported in the registry record. Because no inferential results are reported, there are no p-values or confidence intervals whose multiplicity handling can be assessed.

Missing-data procedures and analysis populations are also not reported in the registry record. The enrollment is 46, but that does not establish how many participants had evaluable measurements, whether all had both TP and TR values, or how many cores contributed to the summaries. The record does not describe exclusions, incomplete outcome data, or any imputation approach. These details matter because the analyzed population and missingness pattern can affect how descriptive results represent participants in the study.

The record lists zero analyses. This means that the registry entry does not give an analysis result or explain the analysis population; it should not be interpreted as proof that no analyses were performed outside the registry. Whether interim analyses occurred, how any analysis was selected, and whether the stated outcomes were changed are not reported in the registry record. The record also does not report a statistical analysis plan. Without those details, readers cannot assess prespecification, selective reporting, or the handling of multiple outcomes and measurements.

11. 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 registry lists one group, MRI Targeted Biopsy, with 46 participants at risk for serious adverse events and 0 affected. It also lists 46 at risk for other adverse events and 2 affected, with 0 deaths. These are the safety figures recorded for this group. No serious adverse event terms are listed among the top serious terms.

These counts should be read as registry summaries, not as a complete account of every possible safety event. The record does not describe the event types behind the two other adverse events, their timing, severity, or relationship to the procedure. It does not report a detailed safety analysis or explain the methods for collecting and classifying events. The zero serious events listed does not establish that serious risks are absent; it describes the count reported in this record for the group and the period covered by its safety reporting.

The study has no separately described comparison group, so the safety counts cannot establish a relative risk versus a control approach. Nor can the zero deaths be interpreted as evidence of a treatment effect. The record’s stated purpose refers to limited risk of infectious complications, but the safety counts alone do not establish whether infection risk was reduced. The infection-specific results are not reported in the registry record.

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

The record describes a study intended to investigate transperineal MRI-targeted prostate biopsy and lists core cancer length as its primary outcome. It also describes TP, TR, and combined measurements. However, the record reports no numerical primary outcome values and no analyses. It therefore does not show the observed core cancer lengths, the amount of variation, or the size and precision of a comparison between approaches.

The study’s single-group classification and lack of a separate control arm are important when interpreting its comparative framing. Merely listing TP and TR measurements does not show that participants were assigned to comparable groups or that a valid between-group estimate was made. The record does not explain whether measurements were paired, how the combined value was formed, or how repeated cores were handled. It is not possible from the registry record to determine what comparison, if any, was statistically conducted.

The secondary outcome about high-grade prostate cancer using Gleason Score is also an endpoint description rather than a result. Its percentage, denominator, and uncertainty are not reported. Similarly, the safety record lists 0 serious adverse events among 46 at risk, 2 other adverse events among 46 at risk, and 0 deaths, but does not describe the other events or offer a comparison. Those counts should not be used to claim that the procedure is safer or that infection risk is limited.

The record’s purpose describes hoped-for access to the whole prostate gland and a limited risk of infectious complications. Those aims are not findings. The record’s terminated status does not explain why the study ended or indicate whether the intended analyses were completed. Overall, the available registry information establishes the study’s stated aims, classification, listed outcomes, and recorded safety counts. It does not support a conclusion that one biopsy approach is superior, equivalent, or safer, and it does not quantify the precision of any such conclusion.

13. Why This Trial Matters Statistically

This record illustrates why a study title and outcome wording do not replace the design description. The title frames the work as a comparative analysis, and the primary outcome description names TP, TR, and TP+TR measurements. Yet the registry classifies the study as single-group and lists allocation as not applicable. Statistical interpretation depends on how data were actually structured and analyzed, not solely on the language used to describe the research question.

It also highlights the distinction between an outcome definition and an outcome result. Naming core cancer length, its measurement unit, summary statistic, and timeframe gives readers a useful outline of what was intended to be measured. Without numerical values, a denominator, and an analysis, however, readers cannot assess the observed pattern or its precision. The same issue applies to the secondary percentage outcome.

The registry record also shows why enrollment and safety counts should be interpreted narrowly. Enrollment of 46 does not identify the analysis population for each endpoint, and the safety counts do not provide event descriptions or a comparative risk estimate. A count reported for one group cannot by itself answer a question about relative effects.

Finally, the listed planning assumptions are distinct from the original study design and from observed evidence. Planning illustrations can explore how sample size might relate to a specified effect under stated assumptions, but they are not observed power and do not supply missing outcome results. Taken together, these features make the record a useful example of how design classification, endpoint reporting, analysis methods, and results must align before a comparative statistical conclusion can be drawn.

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 central limitation for interpretation is that the registry record reports no numerical result for the primary outcome, despite specifying the measurement and timeframe. The median and inter-quartile range for TP, TR, and TP+TR core cancer length are not reported in the registry record. No effect estimate, confidence interval, or test result is reported, so neither the direction nor precision of a comparison can be evaluated.

The study is classified as single-group, without a separate like-for-like control comparison. Although the endpoint description names measurements associated with two approaches, the record does not explain whether data were paired, how the combined measurement was defined, or whether repeated cores were analyzed as clustered within participants. Those omissions prevent assessment of the comparison structure and the assumptions that an analysis might require.

The record lists enrollment as 46, but the number contributing to each outcome and the analysis population are not reported. Missing-data handling, eligibility criteria, participant characteristics, and the denominator for the secondary outcome are also not reported in the registry record. These gaps limit assessment of representativeness and potential bias.

The study is marked terminated, but the reason is not reported in the registry record. No statistical analysis plan, multiplicity strategy, interim-analysis information, or sample-size justification for the original study is reported. The sample-size assumptions describe planning illustrations and do not fill those gaps. Finally, safety reporting gives event counts but does not describe the two other adverse events or report infection-specific results. These limitations mean the registry record supports a design-level description, but not a robust assessment of comparative diagnostic performance or safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Comparative Analysis of Transperineal Versus Transrectal Approaches for MRI-Targeted Biopsy of the Prostate for the Detection and Characterization of Prostate Cancer — NCT03366792.
• Registry record last updated 2022-03-23; status last verified 2022-02.
• Results first posted 2022-03-23.
• 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.

18. Record Summary

The registry record describes a prostate cancer study of MRI-targeted biopsy using the Artemis™ software system. It is classified as single-group, with allocation not applicable and no masking. Enrollment is listed as 46; the status is terminated. The record gives a start date of 2017-10-17 and a primary completion date of 2021-02-26.

The primary outcome is core cancer length in millimeters, summarized by median and inter-quartile range at 2 Months, with TP, TR, and TP+TR measurements named. A secondary outcome concerns the percentage of high-grade prostate cancer using Gleason Score. Numerical outcome results and analyses are not reported in the registry record. Safety entries list 0 serious adverse events among 46 at risk, 2 other adverse events among 46 at risk, and 0 deaths. The reason for termination, the analysis population, and the statistical analysis plan are not reported.