Radiofrequency Ablation for Patients With Esophageal Squamous Cell Neoplasia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Radiofrequency Ablation for Patients With Esophageal Squamous Cell Neoplasia (NCT02047305), a na na study. The primary outcome is Complete Response.

2. Clinical Question

3. Trial Design

This is a completed, single-center trial of endoscopic radiofrequency ablation using the HALO ablation system. The registry lists the design as single group, with allocation NA and masking NONE. Those details mean the record describes a treatment group without a separate randomized comparison group, and it does not indicate masking. The registry lists enrollment as 96 and the condition as esophageal squamous cell carcinoma. Phase is listed as NA.

The registry dates the study start to 2009-01 and primary completion to 2016-08; status is COMPLETED. These entries describe the registered study timeline, not the dates when particular participants were treated or assessed. The record does not report whether enrollment reached its planned target, whether all enrolled participants completed follow-up, or the number included in each outcome analysis.

The treatment plan in the summary is radiofrequency ablation at 3 month intervals until complete eradication. All patients were to undergo endoscopy at 12 months after baseline. Patients with CR were to undergo annual endoscopy with biopsies for 5 years. These are descriptions of the planned treatment and follow-up; the registry record does not report adherence, the number of procedures performed, or follow-up completeness.

The primary outcome is a binary participant-level endpoint, described as the percentage demonstrating complete response at 12 months. The registry lists one outcome measure and reports no analyses. It does not report a control condition, a statistical analysis plan, or a sample-size justification. Sponsor information is listed as Covidien, GI Solutions.

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 Complete Response, measured over 12 Month.

The primary endpoint is Complete Response at 12 months. The registry describes it as complete histological clearance of MGIN, HGIN and SCCA in the treatment area after the initial ablation procedure. The summary also describes CR as no MGIN or worse in biopsies. These definitions make the endpoint a tissue-assessment outcome rather than a symptom measure or a measure of procedure use.

The endpoint is recorded as a count of participants, while its description refers to a percentage. In a binary endpoint, each participant is classified as meeting or not meeting the response definition, and a group percentage expresses the share meeting it. The registry record does not report the observed count or percentage, so no response rate can be interpreted from the posted results described in the record.

Histological clearance is used to assess whether the targeted abnormal tissue remains detectable in the treatment area. Biopsy and endoscopy are the assessment methods named in the study summary. In general, a prespecified endpoint helps make the intended treatment outcome explicit and anchors interpretation to a defined time point. Here, the 12-month assessment is measured from the initial ablation procedure in the primary endpoint description. The registry record does not report the detailed biopsy procedures, criteria for classifying borderline findings, or how unavailable assessments were handled.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a binary primary endpoint: participants either meet the complete-response definition at 12 months or they do not. The endpoint is titled Complete Response and is defined by histological clearance in the treatment area. The record describes the result as a percentage, while its unit is participants and its parameter is a count. These descriptions indicate the intended outcome is participant-level and categorical, but the observed count and percentage are not reported in the registry record.

What does a binary outcome measure?

As a general statistical explanation, a binary outcome records whether a defined event or condition is present for each participant. For this trial, the relevant condition is meeting the CR definition at the specified assessment. A count reports how many participants meet that definition, while a proportion relates that count to the number of participants assessed. The denominator is important: participants enrolled, participants treated, and participants with an evaluable 12-month assessment may not be the same set. The registry record does not report the endpoint denominator or explain how participants without an assessment were handled.

What would uncertainty around a response proportion mean?

As a general statistical explanation, a confidence interval gives a range of values compatible with the observed data under a stated method. It conveys how precisely a response proportion has been estimated; it does not guarantee that the true value lies in the interval, and it does not remove possible bias from study design or missing observations. No observed primary-endpoint estimate or confidence interval is reported in the registry record, so the precision of the response estimate cannot be evaluated.

What can a single-group design estimate?

In general, a single-group study can describe outcomes among the participants observed, subject to how participants were selected, treated, and assessed. It does not by itself provide a direct estimate of the difference between treatment and a control condition. A comparison with an external benchmark would require that benchmark and a rationale for its comparability; neither is reported in the registry record. The trial’s single-group designation and allocation listed as NA are consistent with the absence of a randomized arm-level contrast.

How should the treatment schedule be interpreted?

The study summary describes repeat ablation at 3 month intervals until CR, followed by a 12-month endoscopy for all patients and annual endoscopy with biopsies for patients with CR for 5 years. This describes the intended clinical schedule, not an analysis method. A repeated treatment process can affect how an endpoint is interpreted because participants may have different exposure to treatment before assessment. The registry record does not report session counts, treatment exposure by participant, or the timing of each participant’s CR assessment.

In general, an analysis of a time-specific binary endpoint needs a rule for participants whose assessment is absent or delayed. Analysts may define an analysis population, specify how missing outcomes are treated, or use methods that account for incomplete follow-up. No such rule is reported in the registry record. It is therefore not possible to determine whether the intended estimate was based on all enrolled participants, those treated, or those with an observed assessment.

What is the role of a planning calculation?

In general, a sample-size calculation is a planning exercise: it describes how much information a proposed study might need under stated assumptions. It is not an observed result and does not show that a study had a particular probability of detecting an effect after the data were collected. The registry describes planning illustrations based on the 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 a stated fraction of the observed effect. It also distinguishes participant-per-arm planning for non-time-to-event outcomes from total-event planning for time-to-event outcomes. Those assumptions do not establish that this single-group trial used such a design, and the record does not report the trial’s own sample-size justification or a planning result specific to its primary endpoint.

The registry reports no analyses. It does not describe a statistical model, a confidence-interval method, an adjustment strategy, or a prespecified hypothesis test for the primary outcome. The methods needed to reproduce or evaluate an inferential analysis are therefore not reported in the registry record. The endpoint and design can be described, but they are not substitutes for an analysis plan or observed statistical 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("Radiofrequency Ablation")
n      <- c(96)
events <- c(81)
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  Radiofrequency Ablation  96  81  84.4  75.5  91.0  75.8  90.3  75.8  90.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and no analyses. It does not report whether additional outcomes were assessed outside the listed measure, which outcomes were considered primary or secondary in a full protocol, or whether any formal multiplicity adjustment was planned. As a general statistical principle, multiplicity arises when several hypotheses or outcomes are tested: repeated testing can increase the chance of a false-positive finding unless the analysis accounts for it. Without a reported analysis plan, the handling of multiplicity cannot be assessed.

The record does not describe missing primary-endpoint assessments, exclusions, withdrawals, or the number of participants included in an analysis population. Enrollment is listed as 96, but that does not establish the endpoint denominator. As a general statistical principle, missing outcome data can affect an estimated response proportion when the participants with observed assessments differ systematically from those without assessments. Methods such as prespecified missing-data rules or sensitivity analyses can help evaluate this concern, but no such approach is reported in the registry record.

The registry does not state whether the primary analysis was intended to include all enrolled participants, only treated participants, or only those with an evaluable 12-month assessment. It also does not report the handling of participants who did not reach CR, received repeated ablation, or lacked a biopsy at the specified time. These analysis-population and missing-data details are not reported in the registry record, so the primary outcome cannot be independently reconstructed.

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 registry lists 0 serious adverse events affected and 25 other adverse events affected. It lists 96 at risk for each of those event categories and 0 deaths. No serious adverse event terms are listed. These are counts recorded for the radiofrequency ablation group; they are not comparative estimates because the trial has no separate control group.

Counts at risk identify the group for which the registry records the safety outcome, but the entry does not explain how follow-up time, repeated events, or incomplete safety reporting were handled. The 25 other adverse events affected should not be interpreted as a rate or as a count of event episodes: the record does not provide a definition of whether the affected figure represents participants, episodes, or a particular reporting convention. No event descriptions, severity grading, timing, duration, or assessment of relationship to ablation are reported.

A zero serious-event entry means the registry reports no participants affected in that category; it does not establish that risk is absent. The record also does not provide a comparator or enough detail to characterize the safety profile beyond these listed counts. The reported figures are therefore a limited description of recorded adverse events, not a complete account of all harms or a basis for comparing treatments.

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

The trial’s stated purpose is to study safety and effectiveness of radiofrequency ablation using the HALO system in completely eradicating diseased epithelium in patients with ESCN. The primary endpoint operationalizes the response question as histological clearance of MGIN, HGIN and SCCA in the treatment area at 12 months after the initial ablation procedure. This makes the intended outcome specific to tissue findings at a defined time, rather than a general claim about all aspects of disease or health.

The registry record does not report an observed primary-endpoint count, percentage, confidence interval, or analysis. As a result, it cannot show how often participants met the CR definition or how precisely such a response was estimated. The endpoint definition tells the reader what the study intended to measure; it does not state what the measurements found. The record’s lack of a reported primary result should not be read as evidence of either response or nonresponse.

The single-group design also means the trial does not provide a randomized comparison with another treatment or control. Any outcome observed in this group would describe participants treated within this trial, but would not by itself establish the outcome that would have occurred under an alternative approach. Differences in participant characteristics, treatment exposure, assessment, or follow-up could affect comparisons with other groups, and those comparisons are not reported.

The safety information has similar boundaries. The record lists 0 serious adverse events affected, 25 other adverse events affected, and 0 deaths, but gives no event-level descriptions or comparative group. Those counts do not establish the full nature or severity of adverse events, and they cannot quantify comparative risk.

Thus the registry supports understanding of the study’s population, intervention, intended follow-up, endpoint definition, and recorded safety counts. It does not support a conclusion about the magnitude of complete response, causal effectiveness, or comparative safety. Such conclusions would require outcome analyses and details that are not reported in the registry record.

14. Why This Trial Matters Statistically

This trial is statistically notable for the distinction between a clearly stated endpoint and a reported endpoint result. The registry defines Complete Response through histological clearance in the treatment area at 12 months, which identifies what the investigators intended to measure. Yet it lists no analyses and does not report the observed response count or percentage. A reader therefore cannot estimate the endpoint or its precision from the registry information.

The design also matters. A single-group trial can describe outcomes in its treatment group, but it lacks a concurrent randomized group for estimating a treatment contrast. This distinction is central to interpretation: a defined outcome and a completed study do not, by themselves, provide comparative evidence. The registry labels allocation as NA and masking as NONE, and it does not report a control condition.

The treatment schedule adds an important interpretive feature. Ablation was described at 3 month intervals until CR, with a 12-month endoscopy for all patients and subsequent annual endoscopy with biopsies for participants with CR for 5 years. The primary endpoint is therefore embedded in a treatment and surveillance plan, but adherence and participant-level treatment histories are not reported. Those details would help readers understand the observed population and assessment process if results were available.

The safety entries offer counts but limited context. Without event descriptions, follow-up detail, or a comparator, counts alone cannot support broad claims about safety. The record’s omissions also illustrate why reporting analysis populations, missing outcomes, and methods is important: without them, even a prespecified endpoint may not be independently interpretable.

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 registry record has important reporting limitations for interpreting the primary outcome. Although it identifies Complete Response at 12 months and describes the histological definition, it does not report the number of participants meeting that definition, the number assessed, or the response percentage. It also reports no analyses. This prevents evaluation of the primary result and its precision.

The trial is single group, with allocation listed as NA and masking as NONE. There is no separate control group in the record, so comparative treatment effects cannot be estimated from the described design. The record does not report a statistical analysis plan, a hypothesis test, a confidence-interval method, or an adjustment approach. A sample-size justification is not reported in the registry record.

The relationship between enrollment and endpoint assessment is also unclear. Enrollment is listed as 96, but the registry does not state how many participants received ablation, reached 12-month endoscopy, had biopsies available, or entered an analysis population. It does not report missing-data handling, withdrawals, or deviations from the planned treatment and follow-up schedule.

The safety entries are limited to event counts and at-risk counts. No serious adverse event terms are listed, and the record does not describe the 25 other adverse events, their timing, severity, duration, or relationship to the intervention. It also does not define the reporting convention for affected counts. These limitations constrain both efficacy interpretation and safety characterization.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Radiofrequency Ablation for Patients With Esophageal Squamous Cell Neoplasia — NCT02047305.
• Registry record last updated 2020-05-21; status last verified 2020-03.
• Results first posted 2020-05-21.
• 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 NCT02047305, a completed, single-center trial of radiofrequency ablation using the HALO ablation system for esophageal squamous cell neoplasia. Enrollment is listed as 96; the study start is 2009-01 and primary completion is 2016-08. The design is single group, allocation is NA, masking is NONE, and phase is NA.

The primary outcome is Complete Response at 12 months, defined by histological clearance of MGIN, HGIN and SCCA in the treatment area. The study summary describes repeated ablation at 3 month intervals until CR, followed by endoscopy and biopsy follow-up. The registry lists one outcome measure and no analyses, and it does not report the observed primary response result.

Safety entries list 0 serious adverse events affected, 25 other adverse events affected, and 0 deaths; 96 are listed at risk in each adverse-event category. These counts have limited event-level detail and no comparative context. The registry therefore describes the study question, design, endpoint, and selected safety counts, but does not provide an analyzed primary outcome or comparative treatment estimate.