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 Omission of Surgery in Clinically Low-risk HER2positive Breast Cancer With High HER2 Addiction and a Complete Response Following Standard Anti-HER2-based Neoadjuvant Therapy (NCT04578106), a non-randomized phase 2 study. The primary outcome is Disease-free Survival at 3years.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04578106 |
| Phase | Phase 2 |
| Condition | HER2-positive Breast Cancer, Stage I Breast Cancer |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 5 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Fundacio Clinic Barcelona |
| Results posted | Yes |
2. Clinical Question
Population
Women with primary operable HER2-positive breast cancer, described as HER2-enriched and ERBB2-high, with clinically low-risk disease. The study focused on patients who achieved a complete response after neoadjuvant therapy. The record reports that 5 patients enrolled; 3 showed complete response assessed by MRI. The registry record does not report a complete response assessment for the other 2 using stereotactic-guided vacuum-assisted breast biopsy.
Intervention
Neoadjuvant paclitaxel with trastuzumab and pertuzumab, followed by omission of loco-regional surgery for patients meeting the response criteria. The treatment description specifies weekly intravenous paclitaxel for 12 weeks and a subcutaneous fixed-dose combination of trastuzumab and pertuzumab. The treatment duration after the regimen description is incomplete in the registry record.
Comparator
There was no randomized comparator. The registry describes a prospective, single-arm, non-randomized, open-label study. Although the record includes descriptions labelled omission of surgery and surgery, it does not describe a randomized, like-for-like comparison between those groups. Their presence should not be read as establishing comparative treatment effects.
Primary question
The study aimed to estimate loco-regional invasive disease-free survival at 3 years among patients with a complete response on imaging and stereotactic-guided vacuum-assisted biopsy who omitted loco-regional surgery. The record says participants were lost to follow-up before the 3-year time point, and does not report a numerical survival estimate or confidence interval.
The central statistical question is therefore one of estimation: whether the intended outcome could be assessed in a very small group selected by tumour subtype and response after treatment. The registry record reports enrollment of 5, with 3 MRI-assessed complete responses and no surgery for 2 patients who lacked stereotactic-guided biopsy assessment. It does not provide enough follow-up information to quantify the primary outcome at the stated time point. The design does not support a randomized comparison of surgery with omission of surgery, so the study cannot estimate a causal difference between those approaches from the registry information.
3. Trial Design
This is a prospective, single-arm, open-label, single-centre exploratory phase 2 study. The allocation is non-randomized, and the registry record lists enrollment of 5. The study was intended for women with primary operable HER2-positive breast cancer, specifically HER2-enriched disease with high ERBB2 expression according to a predefined cutoff. The conditions are listed as HER2-positive breast cancer and stage I breast cancer.
The treatment strategy began with neoadjuvant paclitaxel, trastuzumab, and pertuzumab. The arm descriptions specify intravenous paclitaxel at 80 mg/m2 weekly for 12 weeks, alongside a subcutaneous trastuzumab and pertuzumab fixed-dose combination. The descriptions include a loading dose and subsequent maintenance doses, but the treatment duration after the word “for” is absent. The study objective concerned omitting loco-regional surgery and sentinel lymph node dissection in patients who achieved a complete response after treatment.
The registry also contains descriptions labelled omission of surgery and surgery. However, the study is identified as single-group and non-randomized, and the record explicitly warns that these are not like-for-like control groups. No randomized treatment contrast should be inferred from the labels. The record does not report how patients were allocated to those descriptions or provide a basis for comparing outcomes between them.
The study status is terminated. Enrollment was 5. The primary completion date is recorded as 2024-07-16. These registry entries describe the scale and registry status, but do not explain why the study was terminated. The reason for termination, planned enrollment target, and any sample-size justification are not reported in the registry record. Nor does the registry record report an interim-analysis plan or a detailed statistical analysis plan. The small enrollment and loss to follow-up are important when interpreting whether the planned endpoint could be estimated; they do not, by themselves, explain the reasons for the study’s status.
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: Out of 20 patients screened, 13 patients did not fulfill the study criteria (PAM50 subtype other than HER2-Enriched, ERBB2 high, liver metastasis, multicentric tumor). Finally only 5 patients that fulfilled all eligibility criteria and signed the ICF were included
Study treatment
| Stage | Treatment Arm |
|---|---|
| STARTED | 5 |
| COMPLETED | 5 |
| NOT COMPLETED | 0 |
Follow-up after 1 year
| Stage | Treatment Arm |
|---|---|
| STARTED | 5 |
| COMPLETED | 4 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | Treatment Arm |
|---|---|
| Lost to Follow-up | 1 |
Follow up at 3 yrs
| Stage | Treatment Arm |
|---|---|
| STARTED | 4 |
| COMPLETED | 0 |
| NOT COMPLETED | 4 |
Analysis population for the primary outcome, as defined in the registry: After completion of neoadjuvant therapy with paclitaxel and Trastuzumab/pertuzumab, out of 5 patients, only 3 patients showed complete response (assessed by MRI) and 2 patients (no stereo-guided VAB assessment) did not undergo surgery. However, the participants were lost to follow-up before 3-year assessments, so no evaluable 3-year survival data are available
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: The baseline analysis population is the same as the treatment population
| Characteristic | Unit | Treatment Arm |
|---|---|---|
| Participants analysed | 5 | |
| Age, Customized: >= 40 yrs | participants | 5 |
| Sex: Female, Male: Female | Participants | 5 |
| Sex: Female, Male: Male | Participants | 0 |
| Race/Ethnicity, Customized: Caucasian | participants | 5 |
| Region of Enrollment: Spain | participants | 5 |
| Menopausal Status: Postmenopausal (min 12 mnths without menses before neoadyuvance treatment) | participants | 4 |
| Menopausal Status: premenopausal | participants | 1 |
| ECOG baseline: Grade 0 | participants | 4 |
| ECOG baseline: Grade 1 | participants | 1 |
| Previous cancer history: Yes | participants | 0 |
| Previous cancer history: No | participants | 5 |
6. Primary Endpoint
The registry lists the primary outcome as Disease-free Survival at 3years, measured over 3 years.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | years |
| Endpoint classification | Time-to-Event Analysis |
The primary endpoint is described as loco-regional invasive disease-free survival at 3 years. It concerns whether invasive disease-free survival in the breast and regional area can be assessed over the specified follow-up period among patients selected for a complete response and omission of loco-regional surgery. The registry labels the measure as median disease-free survival, with years as the unit and a 95% confidence interval as the dispersion measure. It does not report a median estimate or confidence-interval bounds.
Time-to-event endpoints are used when the timing of an event matters and participants may have different lengths of follow-up. In general, they can use information from participants followed for differing durations, provided event and censoring information is available and handled under an appropriate analysis. Censoring means that a participant’s exact event time is not observed during available follow-up; it does not establish that the event did or did not occur later.
In this study, the registry description says participants were lost to follow-up before 3 years. The record therefore does not establish a complete 3-year outcome assessment for the intended population. The endpoint’s purpose is clear, but the reported information does not allow readers to quantify the 3-year disease-free survival or its precision.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes an exploratory study of surgery omission after anti-HER2-based neoadjuvant therapy, enrolling 5 patients. It reports that 3 showed a complete response by MRI. It also states that 2 patients had no stereotactic-guided vacuum-assisted biopsy assessment and did not undergo surgery. These details do not amount to a complete response determination for all participants using both intended assessment methods.
The primary outcome was intended to estimate loco-regional invasive disease-free survival at 3 years in patients meeting response criteria and omitting surgery. The record says participants were lost to follow-up before the 3-year time point. It gives no numerical estimate, confidence interval, event count, or follow-up distribution for this endpoint. The registry’s description of a median measure and a 95% confidence interval is not itself a reported result. Without the estimate and its uncertainty, the primary endpoint cannot be interpreted quantitatively from this record.
The study has no randomized control group. Consequently, the record cannot establish what would have happened to comparable patients under surgery, nor can it identify a causal effect of omitting surgery. The treatment-arm labels in the record do not change this limitation: the study is classified as single-group and non-randomized, and the record warns that the labelled groups are not a like-for-like comparison. Comparisons between those descriptions should not be treated as randomized evidence.
The small enrollment limits how much information the study can contribute even if outcomes are available. In general, estimates based on few participants can be highly sensitive to each participant’s outcome, and confidence intervals may be wide. That general concern is especially relevant when follow-up is incomplete, because missing outcome information can further reduce the information available for estimating a time-to-event endpoint. The registry record does not provide an endpoint estimate or confidence interval with which to judge the actual precision.
Safety reporting records no serious adverse events among the participants listed as at risk in the treatment groups. Other adverse events are recorded for all participants at risk in each listed group. These are descriptive counts, not a comparison of safety between treatments. The repeated group counts may refer to exposure categories involving the same participants and should not be added as though they were distinct people.
Overall, the posted information documents the study’s aim, design, small enrollment, response-assessment details, loss to follow-up, and adverse-event counts. It does not report a usable 3-year primary outcome result. The study record therefore supports a description of what was attempted and what information was captured, but not a precise estimate of the endpoint or a treatment-effect conclusion.
9. Statistical Methods Explained
The design determines which statistical conclusions are available. This study is prospective, open-label, non-randomized, and described as single-group. In general, randomization helps balance measured and unmeasured prognostic factors across comparison groups, so differences in outcomes can be attributed more credibly to the assigned strategies. Without randomized allocation, differences between groups may reflect patient selection or other factors. Here, the record does not support a randomized comparison, so statistical language about a comparative treatment effect would go beyond what the design establishes.
What does a time-to-event estimate represent?
A time-to-event analysis describes how long it takes for an event of interest to occur, while accounting for participants whose event time is not observed during follow-up. A survival curve is one general way to display the estimated proportion remaining event-free over time. A median time-to-event value, when estimable, is the time by which the estimated event-free proportion has reached a specified midpoint. It is not the same quantity as the event-free proportion at a particular time point. The registry record describes a primary endpoint at 3 years but labels its measure as median disease-free survival. It reports no numerical estimate that would clarify the result.
Why does follow-up completeness matter?
Participants lost to follow-up have unknown outcomes after their last observed contact. In general, time-to-event methods can retain information up to that point, but the validity of the resulting estimate depends on how censoring relates to the chance of an event. If loss to follow-up is associated with prognosis or outcome, a standard analysis may not represent the full enrolled group. The registry record says participants were lost before 3 years, but does not provide dates of last contact, event information, the number with complete follow-up at each time, or an analysis addressing the loss. The effect of missing follow-up on the endpoint estimate cannot therefore be assessed.
How should a confidence interval be read?
In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the analysis. A narrower interval indicates greater precision, while a wider interval indicates less precision; neither a point estimate nor an interval resolves limitations in study design or missing data. The record specifies a 95% confidence interval as the intended measure of dispersion for the primary outcome, but does not provide interval bounds. Precision cannot be judged from the specification alone.
Why are the treatment-arm labels not a control comparison?
The registry lists treatment descriptions for omission of surgery and surgery, but also classifies the trial as non-randomized and single-group and flags that the arms are not a like-for-like control comparison. Statistical comparisons require groups that provide an interpretable basis for estimating a contrast. Without information on allocation, comparability, and a prespecified analysis, a numerical difference between labelled groups would not establish an effect of surgery omission. No analysis records are listed in the registry.
What do the planning illustrations mean?
General sample-size calculations can illustrate how many participants might be needed under stated assumptions to detect an effect of a specified size. The registry’s accompanying planning description says such illustrations use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; for time-to-event outcomes, the calculation concerns total events, while other calculations express participants per arm. It also states that the effect to detect is a fraction of the observed effect. These are planning assumptions, not the trial’s own design justification and not observed power. The registry record does not report the trial’s sample-size justification. Because the study was not randomized and does not report a numerical primary outcome, the planning illustration should not be read as evidence that the study had a particular probability of detecting a treatment effect.
In general, over-dispersion describes variability greater than a chosen statistical model expects. When present, it can make standard errors and confidence intervals too optimistic if the model does not account for the extra variability. The registry information does not identify a count model or report an over-dispersion assessment for this endpoint, so that issue cannot be evaluated as a feature of the trial analysis. More broadly, the statistical analysis plan, handling of missing outcomes, analysis populations, and interim analyses are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity arises when a study tests or estimates multiple outcomes, time points, subgroups, or treatment contrasts. In general, repeated testing can increase the chance of at least one apparently notable finding by chance; prespecified priorities and suitable methods can help readers distinguish confirmatory from exploratory results. The registry lists a primary outcome and secondary outcomes of pathological complete response rate and patient-reported global health status. It reports three outcome measures overall but no analysis records. A multiplicity adjustment or testing hierarchy is not reported in the registry record, so it is not possible to determine whether or how the secondary outcomes were incorporated into a formal testing strategy.
Missing information is a central concern for the primary endpoint. The registry states that participants were lost to follow-up before 3 years and describes 2 patients without stereotactic-guided vacuum-assisted biopsy assessment who did not undergo surgery. The record does not report the number of endpoint events, the follow-up available for each participant, or a method for handling missing response or outcome information. It also does not report sensitivity analyses that would show whether conclusions change under alternative assumptions about missing data.
The analysis population is not described in enough detail to identify who was included in any endpoint analysis. Although enrollment was 5 and 3 patients showed MRI-assessed complete response, the registry provides no numerical primary endpoint result or analysis population count. The protocol’s intended population may be apparent from the study description, but the number actually analyzed for the primary endpoint is not reported in the registry record. No details are given about exclusions, deviations, or how participants who did not meet response criteria were handled. These omissions limit assessment of both the intended analysis and the consequences of incomplete follow-up.
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 |
|---|---|---|---|
| Treatment Arm (Treatment With Paclitaxel) | 0 | 5 | 0.0% |
| Treatment Arm (Treatment With Trastuzumab) | 0 | 5 | 0.0% |
| Treatment Arm (Treatment With Pertuzumab) | 0 | 5 | 0.0% |
| Treatment Arm (Adjuvant Treatment With TDM1) | 0 | 3 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Treatment Arm (Treatment With Paclitaxel) | 0 of 5 |
| Treatment Arm (Treatment With Trastuzumab) | 0 of 5 |
| Treatment Arm (Treatment With Pertuzumab) | 0 of 5 |
| Treatment Arm (Adjuvant Treatment With TDM1) | 0 of 3 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Treatment Arm (Treatment With Paclitaxel) | 5 of 5 |
| Treatment Arm (Treatment With Trastuzumab) | 5 of 5 |
| Treatment Arm (Treatment With Pertuzumab) | 5 of 5 |
| Treatment Arm (Adjuvant Treatment With TDM1) | 3 of 3 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Treatment Arm (Treatment With Paclitaxel) | Treatment Arm (Treatment With Trastuzumab) | Treatment Arm (Treatment With Pertuzumab) | Treatment Arm (Adjuvant Treatment With TDM1) |
|---|---|---|---|---|---|
| diarrhea | Gastrointestinal disorders | 1 of 5 | 4 of 5 | 4 of 5 | 0 of 3 |
| asthenia | General disorders | 2 of 5 | 1 of 5 | 1 of 5 | 1 of 3 |
| alopecia | Skin and subcutaneous tissue disorders | 4 of 5 | 0 of 5 | 0 of 5 | 0 of 3 |
| dysguesia | Metabolism and nutrition disorders | 2 of 5 | 1 of 5 | 1 of 5 | 0 of 3 |
| hiporexya | Metabolism and nutrition disorders | 1 of 5 | 1 of 5 | 1 of 5 | 1 of 3 |
| erythema arms and hands | Skin and subcutaneous tissue disorders | 3 of 5 | 0 of 5 | 0 of 5 | 0 of 3 |
| alat increase | Hepatobiliary disorders | 0 of 5 | 0 of 5 | 0 of 5 | 3 of 3 |
| anemia | Blood and lymphatic system disorders | 1 of 5 | 1 of 5 | 0 of 5 | 0 of 3 |
| headache | Nervous system disorders | 2 of 5 | 0 of 5 | 0 of 5 | 0 of 3 |
| cough | Respiratory, thoracic and mediastinal disorders | 0 of 5 | 1 of 5 | 1 of 5 | 0 of 3 |
The registry lists treatment exposure groups for paclitaxel, trastuzumab, pertuzumab, and adjuvant TDM1. For the first three groups, 5 participants are recorded as at risk for serious adverse events and 0 as affected; 5 are recorded as at risk for other adverse events and 5 as affected. For adjuvant TDM1, 3 participants are recorded as at risk for serious adverse events and 0 as affected; 3 are recorded as at risk for other adverse events and 3 as affected. No deaths are recorded in these groups, and no serious adverse-event terms are listed.
These counts are descriptive registry entries. The repeated counts of 5 across treatment categories should not be added to estimate the number of unique participants, because the groups describe different treatment exposures and may include the same people. The record does not provide event descriptions for the other adverse events, their severity, timing, duration, or relationship to treatment. Nor does it give a comparison group suitable for estimating relative safety. In general, observing no serious adverse events in a small group does not establish that serious events cannot occur. The counts should be read as the reported experience in this study, not as a precise estimate of risk or a comparative safety conclusion.
12. What the Result Does, and Does Not, Mean
The study addresses a clinically and statistically important question: whether selected patients who have a complete response after anti-HER2-based neoadjuvant treatment can be followed without loco-regional surgery. Its registry objective is to estimate loco-regional invasive disease-free survival at 3 years in patients meeting response criteria and omitting surgery. That objective is an estimation question, not a randomized test of surgery against no surgery.
The registry record does show that 5 patients enrolled and that 3 had a complete response assessed by MRI. It also records that 2 patients had no stereotactic-guided vacuum-assisted biopsy assessment and did not undergo surgery. The record states that participants were lost to follow-up before 3 years. It does not report a numerical disease-free survival estimate, confidence interval, event count, or complete follow-up summary. As a result, the intended primary outcome cannot be quantified from the registry record.
This absence of a reported estimate should not be interpreted as a finding that no events occurred, nor as evidence that the endpoint was achieved. In general, an unreported result is different from a zero-event result. The registry does report zero serious adverse events in the listed treatment groups, but that safety observation is separate from the disease-free survival endpoint.
The non-randomized, single-group design also means that no causal comparison with surgery can be made from the record. Descriptions labelled surgery and omission of surgery are not a substitute for a randomized control group, particularly because the record warns that the arms are not like-for-like. The results therefore cannot establish the comparative effect of either strategy.
The study can be read as a small exploratory effort that documents feasibility-related aspects of response assessment and follow-up in a narrowly selected population. It cannot, on the information recorded, provide a precise estimate of the primary outcome or a comparative treatment conclusion. Those are limits on what the registry record establishes, rather than evidence for or against a clinical strategy.
13. Why This Trial Matters Statistically
The statistical importance of this trial lies in the distinction between an appealing clinical question and the evidence needed to answer it. A strategy that omits surgery after a complete response requires careful definition of the eligible population, reliable response assessment, and sufficiently complete follow-up for the outcome of interest. The record makes those elements visible: it specifies HER2-enriched, ERBB2-high disease, describes imaging and biopsy-based response criteria, and targets loco-regional invasive disease-free survival at 3 years.
It also shows how quickly estimation can become difficult in a small exploratory study. Enrollment was 5, with 3 MRI-assessed complete responses; the record notes missing biopsy assessment for 2 patients and loss to follow-up before 3 years. In general, each participant contributes a substantial share of the information when the study is this small. Incomplete outcome data can further reduce precision and make an estimate depend heavily on assumptions about what happened after follow-up ended. Here, the registry does not report an endpoint estimate or confidence interval to assess.
The single-group, non-randomized design is another key statistical feature. It can document what happened in the enrolled group, but it does not provide the randomized comparison needed to isolate the effect of omitting surgery. The treatment labels in the record should not be mistaken for a controlled contrast.
Finally, the registry illustrates why registration details and outcome results must be read separately. A stated endpoint and its planned confidence interval do not constitute an observed result. A sample-size planning illustration is not a statement of observed power, and it does not replace the trial’s own design justification, which is not reported. Together, these distinctions help define what the record can support: a description of a small exploratory study and its reported follow-up limitations, not a precise estimate or treatment-effect conclusion.
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 affect interpretation. Enrollment was 5, leaving little information for estimating a time-to-event endpoint. The registry reports 3 MRI-assessed complete responses, while 2 patients had no stereotactic-guided vacuum-assisted biopsy assessment and did not undergo surgery. The intended population was defined using response on imaging and biopsy, so incomplete assessment makes it difficult to determine how the enrolled participants map onto the population specified for the primary objective.
The record states that participants were lost to follow-up before 3 years, the endpoint’s stated time point. It does not report participant-level follow-up, event counts, a survival estimate, or confidence-interval bounds. The effect of the loss to follow-up on the estimated outcome is therefore unknown. The primary outcome is described as a median measure, but no median result is presented.
The study was non-randomized and single-group. The record’s descriptions of surgery and omission of surgery do not create a valid randomized comparison, and the registry explicitly cautions that these groups are not like-for-like controls. The reason for termination, the planned enrollment target, and the sample-size justification are not reported in the registry record. The statistical analysis plan, analysis populations, interim analyses, handling of missing data, and any multiplicity strategy are also not reported.
The record does not provide enough detail to assess patient-reported outcome results or the secondary pathological complete response outcome. Safety entries lack event descriptions and timing for the other adverse events. Together, these limitations mean the registry supports a limited account of study conduct and reported counts, but not a comprehensive assessment of efficacy, comparative effects, or safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Omission of Surgery in Clinically Low-risk HER2positive Breast Cancer With High HER2 Addiction and a Complete Response Following Standard Anti-HER2-based Neoadjuvant Therapy — NCT04578106.
- Registry record last updated 2026-01-06; status last verified 2026-01.
- Results first posted 2026-01-06.
- 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.
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18. Record Summary
NCT04578106 is a terminated phase 2, prospective, open-label, non-randomized, single-group exploratory study sponsored by Fundacio Clinic Barcelona. It enrolled 5 women with primary operable HER2-positive breast cancer, focusing on HER2-enriched, ERBB2-high disease. The study evaluated omission of loco-regional surgery after neoadjuvant paclitaxel, trastuzumab, and pertuzumab among patients with a complete response.
The primary objective was to estimate loco-regional invasive disease-free survival at 3 years. The registry reports 3 MRI-assessed complete responses, notes that 2 patients did not have stereotactic-guided biopsy assessment and did not undergo surgery, and states that participants were lost to follow-up before 3 years. No numerical primary endpoint estimate or confidence interval is reported. The treatment descriptions labelled surgery and omission of surgery are not a randomized, like-for-like comparison.
The listed treatment groups report no serious adverse events and no deaths. Other adverse events are recorded for all participants at risk in each group. The registry does not report the trial’s sample-size justification, statistical analysis plan, missing-data methods, or reason for termination.