Hot Snare Versus Hot Snare Polypectomy With Saline Injection for Colorectal Polyps: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Hot Snare Versus Hot Snare Polypectomy With Saline Injection for Colorectal Polyps (NCT02239536), a randomized na study. The primary outcome is Complete Resection Rate.

2. Clinical Question

The clinical rationale recorded for the trial is that complete removal is important to prevent recurrence and potential interval cancers, while incomplete resection has been reported in endoscopic removal of neoplastic colorectal polyps. The registry describes the optimal technique for complete resection as unknown and notes limited comparison data for these approaches. These statements explain the study question; they do not establish whether either approach produces better outcomes.

3. Trial Design

NCT02239536 is a completed, randomized, parallel-group trial comparing two polypectomy procedures. One group received hot snare polypectomy, and the other received hot snare polypectomy after saline injection. The registry lists no masking. Enrollment is recorded as 362. The condition is polyp of large intestine, and the sponsor is Bo-In Lee.

The registry gives a start date of 2014-06 and a primary completion date of 2017-12. The phase is listed as NA. The trial description focuses on the removal of colorectal polyps; its brief summary identifies polyps 5 mm or larger, while the stated aim refers to 5-10mm sized polyps. The record does not provide further detail on the eligibility criteria or the characteristics of participants and polyps included in each analysis.

The primary outcome is complete resection rate, with the unit recorded as participants and the timeframe recorded as 2 weeks after. Complete resection is defined as absence of residual polyp in the resection margin. Lateral margin is listed as a secondary outcome. The registry indicates two outcome measures and three analyses, but the primary outcome has several categories or time points and is not reduced to one comparison. The corresponding analysis details and outcome values are not reported in the registry record.

Random allocation supports a planned comparison between the assigned approaches, but the record does not describe the allocation procedure or the analysis population. It also does not report the protocol, sample-size justification, details of follow-up, or the statistical plan. Those omissions limit what can be concluded about how the trial was conducted and how its outcomes were analyzed.

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 Complete Resection Rate, measured over 2 weeks after.

The primary endpoint is complete resection rate. The registry defines complete resection as the absence of residual polyp in the resection margin and gives the timeframe as 2 weeks after. This endpoint is intended to capture whether polyp tissue remains at the resection margin after removal, rather than a later clinical outcome.

The registry records the unit as participants. That matters for interpretation: a participant-based count is not automatically interchangeable with a count of polyps, particularly when a participant could contribute more than one polyp. The record does not explain how multiple polyps, if present, were handled in the endpoint definition or analysis. The primary-outcome population field is empty, and the denominator used for the reported endpoint is not available.

In general, a resection-margin endpoint can assess completeness of removal at a defined assessment time. It does not by itself describe longer-term recurrence or the development of interval cancers. Those are mentioned in the trial rationale, but the primary endpoint as recorded is a margin finding at 2 weeks after. No primary endpoint counts or single comparison are reported in the registry record, so the direction and precision of the trial’s primary result cannot be assessed from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The trial is recorded as randomized, parallel-group, and unmasked. These design labels describe the intended structure of the comparison, but the registry does not report the detailed statistical methods used for the outcome analyses. The explanations below are general statistical context, not claims about procedures used in this trial.

What does randomization contribute?

In general, randomization assigns participants to groups by chance. Its purpose is to make treatment assignment independent of measured and unmeasured baseline characteristics on average, thereby supporting a fair comparison. It does not guarantee that groups will be identical in a particular trial, especially for characteristics that are not measured or when the analysis includes only a subset of randomized participants. The record says allocation was randomized but does not describe how the sequence was generated, how assignments were concealed, or which population was used for analysis.

What does a parallel-group design mean?

In a parallel-group design, participants are assigned to one group and followed under that assigned approach rather than crossing between the study procedures. Here, the two recorded groups correspond to hot snare polypectomy and hot snare polypectomy after saline injection. The registry does not describe whether individual participants or individual polyps were the unit of randomization. That distinction can matter when a participant contributes more than one polyp, because observations from the same participant may be related.

How should a binary endpoint be analyzed?

In general, a binary outcome classifies an observation into one of two states, such as complete resection or residual polyp present. An analysis could compare the number or proportion of participants in each state between groups. The choice of effect measure and statistical model should reflect the randomized unit, the endpoint denominator, and any clustering or repeated observations. The registry records the endpoint unit as participants, but does not report an effect measure, model, adjustment variables, or method for handling multiple polyps.

A useful treatment comparison usually includes an effect estimate with uncertainty, rather than only a count or a significance test. In general, a confidence interval describes uncertainty around an estimated contrast under the chosen method and assumptions. Its width depends on factors including the amount of information and variability in the data. No primary endpoint effect estimate or confidence interval is reported in the registry record, so its magnitude and precision cannot be evaluated.

Why does the analysis population matter?

In general, an intention-to-treat analysis compares participants according to their randomized group, regardless of whether they completed the assigned procedure. Other analysis populations may restrict attention to participants who received treatment or met specified criteria. These approaches can answer different questions and can be affected differently by missing data or exclusions. The registry record does not identify the primary analysis population, report participant flow, or explain how missing endpoint observations were handled. The adverse-event at-risk counts should not be treated as proof of the primary endpoint denominator.

What can be said about planning calculations?

The registry’s planning assumptions describe an illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation; the target effect is stated as a fraction of the observed effect. Such calculations are prospective planning illustrations, not observed power and not evidence that an effect is present. They do not replace the trial’s observed outcome estimate or its uncertainty. The record does not report the trial’s own sample-size justification, so the planning illustration should not be interpreted as the protocol’s design rationale.

What is not established by the methods record?

The registry lists three analyses and two outcome measures, but does not provide enough detail to identify all analysis methods or their relationship to the primary endpoint. It does not report whether analyses were adjusted, whether subgroup analyses were planned, or whether there were interim analyses. Those details cannot be inferred from a randomized design or from the existence of analysis records. In general, transparent reporting of the prespecified analysis, estimate, uncertainty, and analysis population is needed to assess whether the statistical conclusions follow from the design.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and three analyses, and identifies lateral margin as a secondary outcome. It also notes that the primary outcome has several categories or time points and was not reduced to one comparison. The record does not describe how those categories or time points relate to the analyses, which comparison was primary, or whether a particular result was designated as the principal estimate.

In general, testing multiple outcomes, time points, or subgroups can increase the chance of a finding that appears noteworthy by chance. Statistical plans may address this through a prespecified hierarchy or an adjustment for multiple comparisons. The registry does not report whether any such approach was planned or used. Without that information and the full results, the impact of multiplicity cannot be assessed.

The registry record also does not report missing primary-outcome data, reasons for missingness, exclusions, or the methods used to address missing observations. Missingness can affect interpretation if the probability of an observed outcome differs across groups or depends on outcome status. This is general context; the available record does not establish that primary-outcome data were missing.

The endpoint population field is empty, and the record does not identify whether the primary analysis followed an intention-to-treat approach or another analysis population. It also does not provide participant flow for the primary endpoint. Thus, enrollment and adverse-event denominators cannot establish who contributed to the endpoint analysis. The registry record does not report a protocol or a detailed statistical analysis plan, so prespecification of endpoints, time points, and analysis choices cannot be assessed.

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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: perforation (0.0%).

The registry records serious adverse events, other adverse events, and deaths separately. In the hot snare polypectomy group, 0 serious adverse events were recorded among 167 at risk, 17 other adverse events among 167 at risk, and 0 deaths. In the hot snare polypectomy after saline injection group, 0 serious adverse events were recorded among 155 at risk, 13 other adverse events among 155 at risk, and 0 deaths. The listed serious-event term perforation is recorded as 0.0%.

These are counts as entered in the registry, with the stated at-risk denominators. A count of zero means that no event was recorded in that category for the reported group; it does not establish that the underlying risk is zero. In general, safety counts are interpreted in light of how events were defined, collected, and followed, along with the duration of observation. Those details are not reported in the registry record.

The record does not give a statistical comparison, confidence interval, or explanation of how the perforation listing relates to the serious-event totals. The counts should therefore be read descriptively and separately from the primary complete-resection endpoint. They do not, by themselves, establish a difference in safety between the approaches.

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

The record establishes that a randomized, parallel-group comparison was conducted between hot snare polypectomy and hot snare polypectomy after saline injection. It also defines the primary endpoint as complete resection, meaning absence of residual polyp in the resection margin, with a timeframe of 2 weeks after. These details clarify the intended comparison and the outcome concept.

The record does not, however, report a single primary-outcome comparison. It therefore does not allow readers to determine the observed complete-resection result in either group, the estimated difference between groups, or the precision of that estimate. The missing comparison is not evidence that the procedures had the same outcome, nor evidence that one was better. It leaves the principal question unresolved in this registry entry.

The safety entries provide recorded counts for serious events, other events, deaths, and a serious-event term. These are descriptive figures. They do not establish a causal safety difference, and they are not a substitute for complete-resection results. The record does not provide the follow-up details and analysis information needed to interpret these counts beyond their recorded categories and denominators.

In general, a trial result is most informative when the outcome definition, analysis population, effect estimate, uncertainty, and missing-data handling can all be assessed together. Here, the endpoint definition is available, but the primary result and several key analysis details are not reported in the registry record. The study’s rationale explains why comparing the techniques was of interest; it does not determine the result. Conclusions about the relative performance of the approaches should not be drawn from the design description alone.

13. Why This Trial Matters Statistically

This trial’s statistical question is a direct comparison of two procedure strategies, but the registry record illustrates why a clearly stated question and a reported estimate are both needed. The trial is randomized and parallel-group, and the endpoint definition is specific about residual polyp at the margin and the assessment timeframe. Yet without a single primary-outcome comparison, readers cannot connect those design features to an estimate of the difference between groups.

Endpoint units also matter. The primary outcome is recorded in participants, while the clinical procedure concerns polyps. If participants can contribute more than one polyp, the analysis needs to make clear how those observations relate. The registry does not explain this issue, so the endpoint unit and analysis denominator cannot be independently understood from the record alone.

Another statistical lesson is that safety counts and primary efficacy outcomes answer different questions. Adverse-event counts can describe events recorded in each group, while complete resection addresses the specified margin endpoint. Neither set of information can stand in for the other. Likewise, a planning illustration based on an observed effect is not an observed treatment effect and does not resolve the missing primary comparison.

For clinical research readers, this record underscores the value of complete outcome reporting: arm-specific results, a prespecified contrast, an effect estimate with uncertainty, analysis-population details, and an account of missing data. These elements allow readers to distinguish the size of a result from its precision and to judge whether the analysis aligns with the question. Their absence places clear limits on statistical interpretation.

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 primary limitation for interpretation is that the registry does not report one primary-outcome comparison. Although complete resection is defined, no arm-specific endpoint counts or comparative estimate are available in the record. It is therefore not possible to assess the direction, magnitude, or precision of the primary result.

The primary-outcome population field is empty, and the record does not specify the denominator or analysis population for that endpoint. It does not describe how multiple polyps per participant were handled, whether the participant or polyp was randomized, or whether any clustering was considered. These details are relevant because the endpoint is recorded in participants while the procedure concerns polyps.

Other missing details include eligibility criteria beyond the stated size descriptions, participant and polyp characteristics, participant flow, missing endpoint data, and reasons for exclusions. The record does not provide the statistical analysis plan, sample-size justification, adjustment methods, interim-analysis details, or multiplicity approach. These items are not reported in the registry record and cannot be reconstructed from the design labels.

The adverse-event entries are presented as counts with at-risk denominators, but the registry does not describe event definitions, collection procedures, or safety follow-up. Nor does it provide a comparative safety analysis. Finally, the primary endpoint is a margin assessment at 2 weeks after; the registry does not report longer-term outcomes in the material available for this analysis. These limitations constrain what can be inferred from the posted record, rather than indicating that any particular unreported result occurred.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Hot Snare Versus Hot Snare Polypectomy With Saline Injection for Colorectal Polyps — NCT02239536.
• Registry record last updated 2020-04-14; status last verified 2020-04.
• Results first posted 2020-04-14.
• 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

NCT02239536 is a completed randomized, parallel-group trial with no masking listed. It compared hot snare polypectomy with hot snare polypectomy after saline injection for colorectal polyps. Enrollment is recorded as 362, with a start date of 2014-06 and a primary completion date of 2017-12.

The primary endpoint is complete resection, defined as absence of residual polyp in the resection margin, with a timeframe of 2 weeks after. Lateral margin is listed as a secondary outcome. The registry does not report a single primary-outcome comparison or the statistical details needed to interpret one. It records adverse-event counts for both groups, but these do not answer the primary endpoint question. The available record describes the trial design and endpoint, while leaving the principal comparative result unreported.