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 Microwave Ablation With MRI-Guided SBRT Boost in Renal Cell Carcinoma (NCT02782715), a na phase 1, phase 2 study. The primary outcome is Dose-limiting Toxicity With SBRT Combined With Microwave Ablation for Renal Cell Carcinoma.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02782715 |
| Phase | Phase 1, Phase 2 |
| Condition | Carcinoma, Renal Cell |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Wisconsin, Madison |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned patients with non-operable renal cell carcinoma. The registry record lists an enrollment of 3. It also notes that 1 participant did not undergo ablation, which is relevant when considering who could contribute to an endpoint defined around treatment and the period after ablation. Further eligibility details and the characteristics of participants who enrolled are not reported in the registry record.
Intervention
The planned approach combined MRI-guided stereotactic body radiation therapy (SBRT) with microwave ablation (MWA). The record describes a 3+3 dose-escalation design in which three SBRT dose levels would be evaluated: 6 Gy x 5 fractions, 8 Gy x 5 fractions, and 10 Gy x 5 fractions. The record does not establish which dose levels were actually administered.
Comparator
There was no separate control group. The study is recorded as a single-group trial with allocation listed as NA and masking listed as none. Consequently, the registry record does not define a randomized or like-for-like comparison between the combined treatment and another treatment or a control condition.
Primary question
The primary endpoint was the number of dose-limiting toxicities associated with SBRT combined with microwave ablation. A DLT was defined as grade 4 or higher non-hematologic toxicity attributable to treatment, with toxicity defined per NCI CTCAE v5.0. The assessment period was until 30 days after ablation, described as up to 12 weeks on study. The registry record does not report the observed primary endpoint result.
In practical terms, the study was intended to examine whether the combined approach could be delivered while monitoring for treatment-attributable toxicity, as well as to assess local control, survival, and pathologic response. Those secondary aims appear in the record, but their results are not reported in the registry record. The available information therefore describes the research question and design more fully than it describes what happened to participants during follow-up.
3. Trial Design
This was a Phase 1 and Phase 2, single-group study sponsored by the University of Wisconsin, Madison. The registry lists enrollment of 3 and a status of terminated. The study started on 2018-06-28, and the primary completion date is listed as 2023-01-10. The reason for termination and the circumstances surrounding the decision are not reported in the registry record.
The planned intervention paired MRI-guided stereotactic body radiation therapy with microwave ablation. The arm description identifies a 3+3 dose-escalation approach and names three SBRT dose levels: 6 Gy x 5 fractions, 8 Gy x 5 fractions, and 10 Gy x 5 fractions. These are planned dose levels in the description; the registry record does not report whether each level was reached, how many participants received each level, or whether the planned escalation proceeded as intended. Detailed information about treatment delivery beyond the listed dose levels is not reported in the registry record.
There was no random allocation or masking. Because the study had a single group, its design does not support a randomized between-group estimate of the combined treatment's effect. Any interpretation must instead focus on the observations recorded for this small group and on the limits of that design. The listed enrollment is not evidence that all enrolled participants received both interventions or contributed data to every outcome.
The primary endpoint concerned dose-limiting toxicity after the combined approach. Secondary outcomes included local control by RECIST criteria, progression-free survival, overall survival, and tumor pathology of a post-SBRT specimen using H&E staining. The record lists six outcome measures, but it does not provide results for those outcomes in the registry record for this analysis. A participant did not undergo ablation, and the record does not explain how that participant was handled in each analysis. Analysis populations, follow-up completeness, and the actual treatment received by each participant are not reported in the registry record.
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
| Stage | Radiotherapy & Microwave Ablation |
|---|---|
| STARTED | 3 |
| On Treatment | 3 |
| Off Treatment | 3 |
| Completed Ablation | 2 |
| COMPLETED | 2 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | Radiotherapy & Microwave Ablation |
|---|---|
| Withdrawal by Subject | 1 |
Analysis population for the primary outcome, as defined in the registry: 1 participant did not undergo ablation
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.
| Characteristic | Unit | Radiotherapy & Microwave Ablation |
|---|---|---|
| Participants analysed | 3 | |
| Age, Customized: 70-79 years old | Participants | 2 |
| Age, Customized: 80-89 years old | Participants | 1 |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 2 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 3 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | 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 | 0 |
| Race (NIH/OMB): White | Participants | 3 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Dose-limiting Toxicity With SBRT Combined With Microwave Ablation for Renal Cell Carcinoma, measured over Until 30 days after ablation (up to 12 weeks on study).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | dose limiting toxicities |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the number of dose-limiting toxicities associated with SBRT combined with microwave ablation for renal cell carcinoma. The record defines a DLT as grade 4 or higher non-hematologic toxicity attributable to treatment. Toxicities were to be defined according to NCI CTCAE v5.0. Toxicities not caused by treatment, such as pain due to tumor progression, were excluded by the stated definition. The assessment period was until 30 days after ablation, described in the record as up to 12 weeks on study.
A dose-limiting toxicity endpoint is used in early-phase treatment research to characterize serious treatment-attributable toxicity while a treatment approach or dose is being evaluated. In general, a count communicates how many qualifying events were observed under the endpoint definition; interpretation also depends on the number of participants who received the relevant treatment and were assessable during the specified period. A count alone does not describe the full range, timing, or severity of all adverse events.
Here, the registry record says that 1 participant did not undergo ablation, but it does not report the primary endpoint count or give an explicit analysis population for that endpoint. It therefore does not allow the DLT result, or the completeness of DLT ascertainment, to be determined. The record's definition and observation window clarify what the endpoint was intended to capture, but they are not a report of the observed endpoint outcome.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a small, single-group study of MRI-guided SBRT combined with microwave ablation. It lists enrollment of 3 and identifies a primary endpoint based on dose-limiting toxicity. However, the primary endpoint result is not reported in the registry record. The posted information therefore cannot establish how many participants experienced a qualifying DLT or how precisely the study estimated the frequency of such events.
The adverse-event figures are separate from the primary endpoint. The record lists 0 participants with serious adverse events among 3 at risk, and 2 participants with other adverse events among 3 at risk. It also lists 0 deaths. These counts describe the recorded adverse-event categories; they do not supply the missing DLT result. The record does not list serious-event terms, and the available information does not describe the type, severity, timing, or attribution of the other adverse events.
The study's single-group design means there is no randomized control group against which to compare outcomes. Even if outcome results were available, observations from this design would not by themselves separate effects associated with the combined treatment from other explanations, including the underlying condition, participant characteristics, or other care. There is also no basis in the record for comparing the three planned dose levels, because actual dose-level enrollment and outcomes are not reported.
The intended secondary outcomes address different aspects of follow-up. Local control was to be assessed by RECIST criteria, and the record also names progression-free survival, overall survival, and tumor pathology. Their results, definitions beyond the stated descriptions, follow-up duration, and analysis details are not reported in the registry record. These outcomes cannot be inferred from the enrollment figure or the adverse-event counts.
For a reader considering the posted evidence, the central distinction is between a stated study aim and an observed result. The registry record specifies what investigators planned to assess, but the primary outcome data needed to evaluate that aim are absent. Likewise, a terminated status does not explain why the study ended or indicate what the unreported outcomes would have been. The available record supports a description of the design and selected safety counts, not a conclusion about treatment benefit, comparative effectiveness, or the precision of the primary endpoint estimate.
Any planning illustration based on an observed effect must be interpreted cautiously in this setting. The primary result and the observed effect are not reported in the registry record, and planning calculations do not describe trial outcomes or observed power. In addition, a two-arm planning assumption does not match the recorded single-group design. These distinctions matter when using a planning result to think about a future study: it is a conditional illustration, not evidence that the present study demonstrated an effect.
9. Statistical Methods Explained
What does a single-group design tell us?
In general, a single-group study records outcomes among participants receiving the study approach without a concurrent comparison group. Such a design can describe observed events and generate information for further research, but it does not provide a randomized estimate of how outcomes would differ under another treatment or control condition. In this study, the registry records one group receiving the combined SBRT and microwave ablation approach. Allocation is listed as NA, and masking as none. No causal or comparative effect should be inferred from this structure alone.
How should a dose-escalation plan be read?
The registry describes a 3+3 dose-escalation plan with SBRT dose levels of 6 Gy x 5 fractions, 8 Gy x 5 fractions, and 10 Gy x 5 fractions. In general, a dose-escalation design evaluates tolerability at planned dose levels according to prespecified rules. The details of those rules, the actual dose assignments, and the decisions made during escalation are not reported in the registry record. The stated design should therefore not be mistaken for evidence that participants received every listed dose level or that a recommended dose was established.
What does a count endpoint represent?
The primary outcome is a count of dose-limiting toxicities, with a defined treatment-attribution requirement, toxicity threshold, and observation period. In general, a count is a direct way to describe the number of events meeting a definition. To interpret it as a frequency or rate, readers also need a clearly defined denominator and consistent follow-up. A count does not, by itself, describe event timing, recurrence, or the distribution of severity below the specified threshold. The registry record does not report the observed DLT count or the analysis population used for this endpoint.
General statistical interpretation of small counts requires particular caution. When only a small group is observed, a change in the classification of even an event can materially alter the descriptive picture. Estimates based on few observations are typically imprecise; a confidence interval, when reported, represents a range of values compatible with the data and a specified statistical method. No primary endpoint estimate or confidence interval is reported in the registry record, so no such precision assessment can be made from the registry entries.
Why can over-dispersion matter?
In general, count-data methods often rely on assumptions about how much counts vary around their expected value. Over-dispersion means that observed variability exceeds what a simpler count model assumes. If present, ignoring it can make uncertainty appear smaller than it is. Whether over-dispersion is relevant depends on the outcome structure and data; the registry record does not report a count model, dispersion estimate, or analysis of this kind. The primary endpoint is a count, but the name of an endpoint alone does not establish which statistical model was used.
What can be learned from the adverse-event counts?
The posted adverse-event information gives counts of participants at risk and affected for serious and other adverse-event categories. In general, a participant count affected is not necessarily the same as an event count: a participant may experience more than one event, while a participant-level summary records whether any event occurred. The registry record does not provide event-level detail for the other adverse events, nor does it list serious-event terms. The serious and other adverse-event summaries should not be substituted for the DLT endpoint, which has its own definition and attribution rules.
How should planning calculations be interpreted?
The record describes a planning illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that the effect to detect is a specified fraction of the observed effect. In general, sample-size calculations describe how much information a hypothetical study might require under stated assumptions. They are not observed power and do not show whether the completed study had a particular probability of detecting an effect. The registry record does not report the observed primary effect needed to interpret a calculation based on that effect.
The planning assumptions also differ from this study's recorded design: the study is single-group, whereas the illustration assumes equal allocation between two arms. A planning result based on two arms cannot be read as the sample size actually used in this trial or as a direct description of its design. The record states that time-to-event planning tables use total events, while other planning tables use participants per arm; those conventions apply to planning illustrations, not to observed participant outcomes. The actual calculations and their numeric outputs are not reported in the registry record.
What analysis details are unavailable?
The registry lists 0 analyses. It does not report a statistical analysis plan, inferential test for the primary endpoint, confidence interval method, interim analysis, adjustment strategy, or handling of incomplete outcome data. These details should not be inferred from the phase labels, the dose-escalation description, or the endpoint definition. General statistical explanations describe how methods can work; they do not establish that a particular method was used in this study.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists several outcomes: the primary dose-limiting toxicity endpoint and secondary outcomes concerning local control, progression-free survival, overall survival, and tumor pathology. Considering multiple outcomes raises the general issue of multiplicity: when many statistical questions are tested, the chance of at least one apparently notable result can increase unless the analysis plan accounts for that. The registry record does not report whether any multiplicity adjustment was planned or used. It also does not report inferential results for the listed secondary outcomes.
The record names six outcome measures and 0 analyses, but does not provide the analysis methods or results needed to understand how those measures were assessed. It does not state whether secondary outcomes were exploratory, how outcome time points were selected, or how any subgroup or dose-level analyses were handled. Those details are not reported in the registry record and cannot be reconstructed from the outcome titles alone.
Missing-data interpretation is also limited. The record states that 1 participant did not undergo ablation, but it does not explain the reason, whether that participant received SBRT, or how the participant was included in each outcome analysis. It does not report outcome-specific denominators, withdrawals, loss to follow-up, or how missing measurements were handled. The enrollment figure should not be assumed to be the analysis population for every endpoint.
In general, conclusions can depend on which participants are included and how missing outcomes are treated. This is especially important when the group is small and the endpoint is tied to treatment exposure and a defined follow-up period. The registry record does not describe an intention-to-treat population, a safety population, or an endpoint-specific evaluable population. Consequently, the available information cannot establish whether outcome ascertainment was complete or whether exclusions affected the results.
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 |
|---|---|---|---|
| Radiotherapy & Microwave Ablation | 0 | 3 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Radiotherapy & Microwave Ablation | 0 of 3 |
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 |
|---|---|
| Radiotherapy & Microwave Ablation | 2 of 3 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Radiotherapy & Microwave Ablation |
|---|---|---|
| Nausea | Gastrointestinal disorders | 2 of 3 |
| anemia | Blood and lymphatic system disorders | 1 of 3 |
| lymphopenia | Immune system disorders | 1 of 3 |
| headache | General disorders | 1 of 3 |
| Fatigue | General disorders | 1 of 3 |
| back pain | Musculoskeletal and connective tissue disorders | 1 of 3 |
The adverse-event record lists 0 serious adverse events among 3 participants at risk, 2 participants with other adverse events among 3 at risk, and 0 deaths. These are the registry's reported participant-level counts for the listed categories. The record does not list serious adverse-event terms. For the other adverse events, it does not provide the event names, grades, timing, treatment attribution, or number of events per affected participant.
These summaries should be distinguished from the primary endpoint. The primary outcome concerns dose-limiting toxicities defined as grade 4 or higher non-hematologic toxicity attributable to treatment within the specified period. The adverse-event figures do not show how many events met that definition, and the primary endpoint result is not reported in the registry record. The category “other adverse events” should not be read as a count of DLTs.
In general, a zero count in a small study means that no events in that category were recorded among the listed participants at risk; it does not establish that the event cannot occur or precisely characterize its frequency in a wider population. The record does not report the completeness or duration of adverse-event follow-up beyond the endpoint timeframe. These counts therefore describe the posted safety information without providing a complete account of safety outcomes.
12. What the Result Does, and Does Not, Mean
The registry record identifies a study that set out to assess the safety and feasibility of combining MRI-guided SBRT with microwave ablation for non-operable renal cell carcinoma. It specifies a primary endpoint based on treatment-attributable dose-limiting toxicity and lists additional outcomes for local control, survival, and tumor pathology. It also provides limited adverse-event counts. These details help define the research question and the type of information the study was intended to collect.
They do not establish the observed primary endpoint result. The DLT count is not reported in the registry record, and the record does not give an endpoint analysis population. Results for the listed secondary outcomes are also not reported. Accordingly, the available information does not show the local-control, survival, or pathologic-response outcomes, or how those outcomes varied across the planned dose levels.
The listed adverse-event counts describe what was recorded in the serious and other categories, but they do not replace the DLT endpoint or provide a full account of event types and severity. The study's single-group design also means that the record does not provide a randomized comparison with another treatment or control condition. Without such a comparison, observed outcomes would not by themselves establish that the combined approach caused a particular result.
The status is terminated, but the reason for termination is not reported in the registry record. That status alone cannot explain the amount of follow-up, the availability of outcome data, or the decision to stop. It should not be treated as a favorable or unfavorable result.
Statistically, the record supports a cautious description of the planned design, endpoint definition, enrollment, and selected adverse-event counts. It does not support a conclusion about efficacy, comparative benefit, or the precision of a DLT estimate. Planning calculations are illustrations under stated assumptions, not observed power and not evidence that an effect was detected. The distinction between design information and reported outcome data is essential when interpreting a registry entry with limited results.
13. Why This Trial Matters Statistically
This study is statistically informative as an example of the gap that can arise between a clearly described research question and the outcome information available in a registry record. The study identifies a defined primary safety endpoint, a specified attribution rule, and an observation window. Those features matter because they determine which events would count as dose-limiting toxicity and when they would be assessed. Yet the observed DLT result and its analysis population are not reported in the registry record.
The single-group design is another important feature. It is suited to describing observations within the treated group, but it does not create a randomized comparison for estimating differences between treatment strategies. This limits what can be concluded even when outcomes are available. The recorded design should therefore shape interpretation before any numerical result is considered.
The dose-escalation description also highlights the difference between planned and observed treatment. The record lists three intended SBRT dose levels, but does not state which were administered or how participants were distributed across them. Without those details, readers cannot assess dose-specific safety or connect an outcome to a particular level.
Finally, small enrollment and incomplete outcome reporting make precision and missingness central concerns. The adverse-event counts offer some safety information, but no primary endpoint estimate or secondary outcome results are available in the registry record. Sample-size planning illustrations, if considered, remain assumption-based planning tools and do not substitute for observed results. Together, these features show why study design, analysis populations, outcome reporting, and uncertainty must be considered separately when interpreting early-phase clinical research.
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 registry record identifies enrollment of 3, a single-group design, and a terminated status, but gives limited information about the conduct and results of the trial. The reason for termination is not reported in the registry record. Nor does the record say whether the planned dose-escalation proceeded through all listed levels, which participants received each level, or what treatment each participant actually received.
One participant did not undergo ablation, but the record does not explain why or how that participant was handled in the primary and secondary outcome analyses. It does not report outcome-specific denominators, withdrawals, follow-up completeness, or missing-data methods. This makes it difficult to determine which participants could contribute to the endpoint that was defined around the period after ablation.
The primary endpoint result is not reported, and secondary outcome results are also absent. The record does not provide event-level details for other adverse events or serious-event terms. It does not report a statistical analysis plan, inferential methods, uncertainty estimates, or the handling of multiple outcomes. These omissions limit assessment of both the study findings and their precision.
The design itself imposes a further limitation: there was no randomized comparator. The study therefore cannot provide a direct randomized comparison with another approach. The planned dose levels do not constitute separate comparison groups unless actual allocation and outcome information support such an analysis, and those details are not reported in the registry record. The available information is consequently insufficient to evaluate dose-specific outcomes, comparative effects, or the completeness of safety follow-up.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Microwave Ablation With MRI-Guided SBRT Boost in Renal Cell Carcinoma — NCT02782715.
- Registry record last updated 2024-03-20; status last verified 2024-02.
- Results first posted 2024-03-20.
- 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
The registry record describes a Phase 1 and Phase 2, single-group study of MRI-guided SBRT combined with microwave ablation for non-operable renal cell carcinoma. Enrollment is listed as 3; the study status is terminated. The primary endpoint was the number of treatment-attributable dose-limiting toxicities, defined using grade 4 or higher non-hematologic toxicity and assessed until 30 days after ablation, described as up to 12 weeks on study. One participant did not undergo ablation.
The record lists 0 serious adverse events among 3 at risk, 2 participants with other adverse events among 3 at risk, and 0 deaths. It does not report the primary endpoint result, secondary outcome results, the reason for termination, or the actual treatment and dose-level experience of participants. The single-group design provides no randomized control comparison. Interpretation is therefore limited to the stated design and posted adverse-event counts.