This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Cryoablation for Invasive Breast Carcinoma Following Neoadjuvant Therapy (NCT01388777), a na phase 2 study. The primary outcome is Rate of Complete Tumor Ablation.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01388777 |
| Phase | Phase 2 |
| Condition | Breast Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 1 |
| Arms in the primary outcome | n/a |
| Lead sponsor | M.D. Anderson Cancer Center |
| Results posted | Yes |
2. Clinical Question
Population
Participants with invasive breast cancer following neoadjuvant therapy. The registry record lists an enrollment of 1.
Intervention
Ultrasound-guided cryoablation using the Visica 2™ Treatment System, followed by re-imaging and complete surgical resection.
Comparator
There is no separate comparator arm. This is a single-group study, and allocation is listed as not applicable.
Primary question
How many participants have complete tumor ablation in the target lesion, as assessed by pathologic review of the surgical specimen?
The study also sets out to examine the safety of the procedure. The registry describes cryoablation as freezing and destroying cancer tissue with a thin probe, and identifies ultrasound guidance as part of the approach under study. The planned sequence matters to interpretation: the lesion is treated, re-imaged, and then surgically removed, allowing the primary endpoint to be assessed in the surgical specimen.
This is a question about a pathology finding after a procedure, not a comparison of outcomes between randomized treatment groups. The registry record does not report a comparator or a reported primary-endpoint result. It therefore does not establish how the finding would compare with another treatment, nor does it provide an estimate of the frequency of complete ablation in a larger group. The posted record describes the question the pilot was designed to address, but does not give an efficacy analysis that answers it.
3. Trial Design
This is a Phase 2 pilot study with a single-group model. The registry lists allocation as not applicable and masking as none. The intervention description gives a sequence of cryoablation therapy, re-imaging, and complete surgical resection. The study title and official title identify the setting as invasive breast carcinoma following neoadjuvant therapy; the listed condition is breast cancer.
The registry lists enrollment as 1 and the status as terminated. Its recorded start date is 2012-01-24, and its primary completion date is 2017-06-14. Those record entries describe the study timeline and status; they do not explain why the study was terminated. The reason for termination is not reported in the registry record.
Because there is no separate control group, this design cannot make a randomized, like-for-like comparison of cryoablation with another intervention. The single-group structure can describe what was observed among participants in that group, if outcome results are reported, but it cannot by itself separate an intervention effect from other possible explanations for an observation. Here, the registry record does not include a primary outcome analysis, so even a descriptive estimate of the primary endpoint is unavailable.
The record identifies the Visica 2™ Treatment System and cryoablation as intervention entries, and lists surgical resection as another procedure. It does not report a masking procedure or a comparator. Further details about the protocol, conduct, or rationale for the sample size are not reported in the registry record. In particular, the record does not provide a reason for the enrollment of 1 or explain the termination.
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.
Before assignment: Early termination leading to small number of subjects analyzed.
Overall Study
| Stage | All Participants Enrolled and Started Treatment |
|---|---|
| STARTED | 1 |
| Cryoablation | 1 |
| COMPLETED | 1 |
| NOT COMPLETED | 0 |
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.
Population: Overall number of baseline participants does not differ from the number of participants assigned to the arms/overall.
| Characteristic | Unit | All Participants Enrolled and Started Treatment |
|---|---|---|
| Participants analysed | 1 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 1 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 |
| Race (NIH/OMB): White | Participants | 0 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | Participants | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Rate of Complete Tumor Ablation, measured over From cryoablation through 30 days from surgery.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is titled Rate of Complete Tumor Ablation. It is expressed as a count of participants, and the registry description says that complete ablation in the target lesion will be evaluated by pathologic review of the surgical specimen. The stated timeframe runs from cryoablation through 30 days from surgery.
Pathologic review after surgical removal provides an assessment of the treated lesion in tissue. In general, a pathology-based endpoint can characterize what is found in the specimen after an intervention, rather than relying only on imaging or symptoms. That is the role this endpoint is intended to serve in this study. The registry does not report a definition of the pathology criteria used to classify complete ablation, so the operational details of that classification are not available.
The record specifies a count measure, but it does not post the observed count or a rate. No efficacy analysis is listed. Consequently, the endpoint description establishes what investigators intended to assess, but the posted record does not show how many participants met the criterion, how the result was estimated, or how precise an estimate might be. The endpoint should not be read as a reported finding simply because it appears as the primary outcome.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central statistical limitation is that the registry record contains no reported primary-endpoint analysis. It lists one outcome measure and 0 analyses, while enrollment is listed as 1. The endpoint is described as a count of participants whose target lesion shows complete tumor ablation on pathologic review, but the record does not state the observed count. There is therefore no posted efficacy estimate to interpret, and no basis in the record for describing the frequency of complete ablation.
The study is a single-group pilot, not a randomized comparison. Even if a result were available, a finding within this group would not directly establish how the outcome compares with another treatment or with a control condition. Without a comparator, differences attributable to the intervention cannot be distinguished from other explanations using a between-group contrast. In this record, the absence of an outcome result means that even a within-group endpoint estimate cannot be described.
Precision is also a major concern. With enrollment listed as 1, any reported proportion based on the full enrolled group would be highly dependent on the outcome for that participant. A confidence interval, if reported, would communicate uncertainty around an estimate; no confidence interval or other uncertainty measure is reported. It would be inappropriate to substitute a confidence interval or test result that the registry does not provide.
The safety entries should be interpreted separately from efficacy. The adverse-event group is titled All Participants Enrolled and Started Treatment and lists 1 participant at risk for serious adverse events, with 0 affected, and 1 at risk for other adverse events, with 0 affected. Deaths are listed as 0. These counts describe the posted safety fields; they do not establish that risks are absent or precisely estimated. A small denominator gives little information about uncommon outcomes, and the registry record does not give additional safety analysis or follow-up detail.
The status is terminated, but the record does not report a termination reason. The available information cannot establish whether termination was related to efficacy, safety, recruitment, funding, or another consideration. The record supports a limited description of the intended design, endpoint, and posted event counts, not a conclusion about treatment effect or comparative safety.
Planning illustrations elsewhere on the page should likewise be kept separate from observed evidence. They are not observed power and do not repair the absence of a reported endpoint result. The posted trial design is single-group, whereas the described planning assumptions concern equal allocation between two arms. Those calculations are illustrative rather than the trial's own design or analysis.
9. Statistical Methods Explained
The registry record identifies a binary primary outcome measured as a count of participants, but it reports no analysis. The explanations below are general statistical context, not a description of methods confirmed to have been used in this study.
What a count endpoint can show
For a binary endpoint, each participant is classified according to whether the defined event occurred. A count reports how many participants meet the criterion; a rate or proportion relates that count to the relevant group size. In this study, the intended event is complete tumor ablation in the target lesion, assessed on the surgical specimen. The record gives neither the observed count nor a reported rate. It also does not specify the pathology criteria in enough detail to assess how consistently the classification could be applied.
When a binary result is estimated from a small group, the estimate can be very imprecise. A confidence interval is a way to express the uncertainty associated with an estimate under a statistical model. It is not a guarantee about the result, and its width depends in part on the amount of information in the data. No estimate or confidence interval for this endpoint is reported in the registry record. Because enrollment is listed as 1, any hypothetical estimate would be especially sensitive to the outcome of that participant; this is a general observation about sparse binary data, not a substitute for the missing analysis.
Why a comparison group matters
A single-group study can describe outcomes among the participants who receive the intervention. It does not provide a concurrent comparison that helps distinguish an intervention-associated outcome from other influences. Random allocation, when used in a comparative trial, is one way to support a fair comparison by assigning participants to groups. This study lists allocation as not applicable and its model as single group. It therefore has no randomized contrast to interpret. These design features do not invalidate a descriptive observation, but they limit the kinds of causal or comparative conclusions a study can support.
What inferential results would add
In general, an analysis might report an effect estimate alongside an uncertainty interval, and could use a statistical test if a relevant hypothesis and analysis plan had been specified. A p-value, where appropriate, describes how compatible the observed data are with a stated null model under the assumptions of the test. It does not measure the size or clinical importance of an effect. Here, no test, p-value, effect estimate, or interval is reported. The statistical analysis plan is not reported in the registry record, so it is not possible to say which methods were intended or whether an analysis was performed outside the posted record.
Why sparse data need care
General statistical methods for counts often rely on assumptions about how outcomes vary across participants. Over-dispersion is a general term for variability greater than a model expects; when present, methods that assume less variation can make uncertainty appear smaller than it is. The registry record does not report an over-dispersion assessment, and the available information does not support assessing one. With an enrollment of 1, there is also very little information for assessing the shape or variability of a group-level outcome distribution. This is a general limitation of the data scale, not evidence that a particular model was used or violated.
Planning calculations are not evidence about the observed result. The sample-size illustrations use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a stated fraction of the observed effect. They are planning illustrations, not the trial's design, and do not represent observed power. The trial itself is a single-group study. The registry record does not report the underlying observed effect or a trial-specific sample-size justification, so the illustrations should not be mistaken for a protocol calculation or a validation of this study's enrollment.
What can be concluded from the posted methods information
The record describes the intervention sequence and the intended pathology endpoint, but it does not provide enough information to reconstruct an analysis. The primary outcome population is blank, and no analysis population or handling of missing endpoint assessments is reported. It is also not reported whether the endpoint was evaluated for every participant who began treatment, how the pathology assessment was conducted, or whether any outcome data were unavailable. These details are important because the denominator and classification process affect interpretation of a count or rate. Without those details and without posted outcome results, the appropriate statistical reading is descriptive: the registry states what was to be measured, but it does not report the analysis needed to quantify that endpoint.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure, identified as the primary endpoint, and 0 analyses. It does not report a broader family of endpoints, a statistical testing hierarchy, or an adjustment for multiple comparisons. Whether additional outcomes were assessed outside the posted record is not reported in the registry record. General statistical practice treats multiplicity as relevant when several outcomes or hypotheses are tested, because interpreting many tests without a plan can increase the chance of highlighting a result that appears unusual by chance. The record does not allow that issue to be assessed beyond the listed outcome measure.
The primary outcome population field is blank. The record therefore does not define which participants were included in an efficacy analysis, or whether an intention-to-treat, per-protocol, or other analysis population was planned. Those labels describe different ways of defining who contributes to an analysis; none should be assigned to this study without documentation. The adverse-event table has its own listed group, titled All Participants Enrolled and Started Treatment, but that label does not establish the population used for the primary endpoint.
Missing endpoint data and their handling are not reported in the registry record. The entry does not say whether any pathology assessments were unavailable, how missing values would be treated, or whether a sensitivity analysis was planned. In general, missing outcome information can affect both the denominator and the interpretation of a result. Since no primary result is posted, the extent or effect of missingness cannot be evaluated.
The analysis plan, including any prespecified approach to multiplicity, missing data, or population definitions, is not reported in the registry record. The absence of these details should be read as a limitation of the available record, not as evidence that a particular method was or was not used elsewhere.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| All Participants Enrolled and Started Treatment | 0 | 1 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| All Participants Enrolled and Started Treatment | 0 of 1 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| All Participants Enrolled and Started Treatment | 0 of 1 |
The posted adverse-event group is titled All Participants Enrolled and Started Treatment. It lists 1 participant at risk for serious adverse events and 0 affected. For other adverse events, it lists 1 at risk and 0 affected. Deaths are listed as 0. These are the counts shown in the registry record, not an estimate of risk with a reported uncertainty interval.
A zero count in a group this small does not show that an event is impossible or that the procedure has no safety risk. It means that no affected participant is recorded in these entries for the listed group. A small denominator provides limited information about events that may occur infrequently, and these figures cannot establish comparative safety because there is no control group.
The registry record does not provide additional detail about event definitions, severity grading, duration of follow-up, or how the safety counts were collected. It also does not report a safety analysis beyond the posted counts. The entries should therefore be read narrowly: they summarize the recorded serious-event, other-event, and death counts for the listed group, without supporting broader conclusions.
12. What the Result Does, and Does Not, Mean
The record establishes that a Phase 2 pilot study was registered to examine ultrasound-guided cryoablation for invasive breast carcinoma following neoadjuvant therapy. It identifies a single-group treatment sequence and a primary endpoint based on pathologic review of the surgical specimen. It also gives safety counts for a group listed as having enrolled and started treatment.
What the record does not establish is the rate of complete tumor ablation. Although the endpoint is named and described, no observed primary-outcome count, rate, effect estimate, or uncertainty measure is posted. There is consequently no efficacy result to characterize as favorable or unfavorable, precise or imprecise. The absence of a reported result is not itself a result about the procedure.
The design also does not support a randomized comparison. There is no separate comparator arm, and the record lists allocation as not applicable. Thus, the posted information cannot show how outcomes compare with another approach. Nor can the safety counts establish that the procedure is safer or less safe than an alternative.
The enrollment of 1 and the terminated status are important context, but the registry record does not explain the reason for termination. It would be speculation to attribute that status to an outcome, safety concern, recruitment difficulty, or any other cause. The record also does not report the analysis population, the handling of missing data, or a statistical analysis plan. These absences limit interpretation independently of the small enrollment.
In general, pilot studies can be informative about whether a research question and measurement approach merit further study, but this record does not report enough outcome or process detail to judge those aspects. Its strongest supported contribution is to describe the planned question and document the small enrolled group and posted event counts. It cannot establish treatment effectiveness, comparative benefit, or a precise safety profile.
13. Why This Trial Matters Statistically
This trial is statistically notable because the gap between a clearly stated endpoint and an absent endpoint result is especially visible. The registry names a pathology-based measure of complete tumor ablation, but posts 0 analyses and no observed result for that measure. For readers, this distinction is fundamental: registration of an outcome does not mean that its analysis or result is available in the record.
The design also illustrates what a single-group study can and cannot answer. It can be structured to describe an outcome among participants who receive an intervention. Without a control group, it cannot provide a randomized estimate of how that outcome differs from an alternative. A pilot can frame a question for further investigation, but a pilot label does not by itself supply evidence of efficacy or establish an adequate sample size.
The enrollment of 1 makes the importance of uncertainty concrete. Statistical summaries based on very sparse data are limited, and even a count needs its denominator and endpoint classification rules to be interpretable. Here, the registry does not provide the primary outcome count, interval, or analysis details. The absence of those items prevents readers from judging either the observed result or its precision.
Finally, the record shows why safety counts must be read in context. Zero affected participants are posted for both serious and other adverse events, but the group at risk is listed as 1. Such counts are not a complete characterization of safety, and they do not support comparison with another treatment. The terminated status adds context, but without a stated reason it cannot be used to infer what happened. Statistically, the most responsible reading is to distinguish documented design and counts from conclusions the registry does not report.
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.
Several limitations specific to this study constrain interpretation. The registry lists enrollment as 1, leaving very little information for estimating a group-level endpoint or characterizing variability. More importantly, it does not report the observed primary-endpoint count or any analysis. The endpoint is described, but its result cannot be reconstructed from the record.
The single-group design has no comparator arm, so it does not support a randomized comparison. The masking entry is none, and the record does not describe how pathology assessment was performed or whether outcome classification was masked. The detailed criteria for complete tumor ablation are not reported in the registry record, so readers cannot assess how the endpoint was operationalized.
The status is terminated, but the reason is not reported in the registry record. The record does not say whether termination was planned, related to recruitment, related to safety, or due to another consideration. The primary outcome population is blank; analysis populations and the handling of missing endpoint data are also not reported. These omissions leave uncertainty about the intended denominator and the process used to reach an endpoint result.
The timeframe is stated as from cryoablation through 30 days from surgery, but further detail about assessment timing and follow-up is not available. The registry identifies the intervention components, yet does not provide enough information to assess implementation or adherence. No sample-size justification, statistical analysis plan, or inferential result is reported. The planning illustrations should not be treated as the trial's own design or as a substitute for those missing details.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Cryoablation for Invasive Breast Carcinoma Following Neoadjuvant Therapy — NCT01388777.
- Registry record last updated 2018-07-17; status last verified 2018-06.
- Results first posted 2018-07-17.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry describes a Phase 2 pilot study of cryoablation for invasive breast carcinoma following neoadjuvant therapy. It is a single-group study with allocation listed as not applicable and masking listed as none. The intervention sequence is cryoablation, re-imaging, and complete surgical resection. Enrollment is listed as 1; the study status is terminated.
The primary endpoint is the count of participants with complete tumor ablation in the target lesion, assessed by pathologic review of the surgical specimen. The record lists one outcome measure and 0 analyses, and does not report an efficacy result. The adverse-event entries list 1 participant at risk and 0 affected for serious events, 1 at risk and 0 affected for other events, and 0 deaths.
The termination reason, primary analysis population, missing-data approach, and statistical analysis plan are not reported in the registry record. The posted information describes the study question and design but does not establish an efficacy estimate or comparative safety finding.