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 Conformal Radiation Therapy in Treating Patients With Metastatic Cancer Outside the Brain (NCT00550654), a na phase 2 study. The primary outcome is 6-month Local Control (i.e., Complete Response, Partial Response, or Stable Disease) at All Treated Sites of Metastatic Disease.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00550654 |
| Phase | Phase 2 |
| Condition | Kidney Cancer, Melanoma (Skin), Metastatic 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 | National Institutes of Health Clinical Center (CC) |
| Results posted | Yes |
2. Clinical Question
Population
The intended population was patients with metastatic cancer outside the brain. The registry lists kidney cancer, melanoma, metastatic cancer, ovarian cancer, sarcoma, and an unspecified adult solid tumor as conditions. It does not provide detailed eligibility criteria in the record. The population available for efficacy assessment is especially important to interpret: the record states that no data or specimens were collected and that the study was terminated due to poor accrual.
Intervention
The study evaluated hypofractionated, highly conformal radiation delivered with helical tomotherapy. The arm description specifies treatment once every other day over 5 days, for a total of 3 fractions. Listed interventions also include 3-dimensional conformal radiation therapy, image-guided radiation therapy, tomotherapy, and questionnaire administration.
Comparator
This was a single-group study, with allocation recorded as NA and masking as none. There was no like-for-like control group identified in the registry. The study therefore was not designed as a randomized comparison of radiation against another treatment or against no radiation.
Primary question
The primary question concerned local control at 6 months across treated metastatic sites. Local control was defined as complete response, partial response, or stable disease. The endpoint describes status at treated sites, rather than overall disease control or a comparison between treatment groups. The registry reports no collected data or specimens, so it does not provide an observed primary endpoint result. It also does not report an estimate of the proportion with local control or its uncertainty.
3. Trial Design
The registry describes a phase II, single-group study of conformal radiation therapy for metastatic cancer outside the brain. The sponsor was the National Institutes of Health Clinical Center (CC). The study started in 2007-10, had a primary completion date of 2010-05, and is listed as terminated. Enrollment is recorded as 1. The registry attributes termination to poor accrual.
The treatment arm was called Radiation Therapy in Metastatic Cancer. Its description specifies hypofractionated, highly conformal radiotherapy using helical tomotherapy once every other day over 5 days, for a total of 3 fractions. The intervention list also names 3-dimensional conformal radiation therapy and image-guided radiation therapy, as well as tomotherapy and questionnaire administration. The registry does not report how these listed intervention terms were implemented in relation to each other beyond the arm description.
Allocation is recorded as NA, masking as none, and the model as single-group. There is therefore no randomized control arm to support a between-group treatment comparison. The registry record does not report a detailed statistical analysis plan, an interim-analysis plan, or a sample-size justification. The sample-size planning illustrations associated with the posted results are not evidence of the original protocol's intended enrollment or design.
The study included a primary local-control endpoint at 6 months and secondary outcomes concerning adverse events, local progression, 12-month local control, motion during treatment, pain, and tumor doubling times. However, the registry says no data or specimens were collected. It reports no analyses. Consequently, the design and planned measures can be described, but they do not establish that efficacy outcomes were measured or that treatment exposure and follow-up were completed as intended.
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 | Radiation Therapy in Metastatic Cancer |
|---|---|
| STARTED | 1 |
| COMPLETED | 1 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: No data/specimens were collected. Study was terminated due to poor accrual.
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 | Radiation Therapy in Metastatic Cancer |
|---|---|---|
| Participants analysed | 1 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 |
| Age, Categorical: >=65 years | Participants | 1 |
| Age, Continuous | years | 71.6 (SD NA) |
| Gender: Female | Participants | 0 |
| Gender: Male | Participants | 1 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 1 |
| 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 | 1 |
| 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 6-month Local Control (i.e., Complete Response, Partial Response, or Stable Disease) at All Treated Sites of Metastatic Disease, measured over 6 months.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was local control at 6 months across all treated sites of metastatic disease. The registry defined local control as complete response, partial response, or stable disease. Complete response meant disappearance of the target lesion. Partial response was defined as a decrease of at least 50% in maximal dimension compared with pretreatment imaging. Stable disease meant the lesion did not qualify as complete response, partial response, or progression. Progression was defined as an interval increase in the target lesion's maximal dimension.
In general, a local-control endpoint focuses on what happens at the sites that received local treatment. It can describe whether treated lesions have disappeared, decreased, remained stable, or progressed by the specified assessment time. That is a different question from whether cancer is controlled throughout the body, whether new sites develop, or whether patients live longer. The registry also listed 12-month local control among secondary outcomes, but the primary time point was 6 months.
The endpoint is clinically interpretable only when the treated sites are assessed consistently and the response categories are applied as defined. The registry record does not report collected data or specimens, and it provides no primary endpoint result. Thus, the endpoint definition is available, but the posted record does not show an observed local-control estimate or its precision.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The key interpretive fact is that this study has no reported primary endpoint result. Although the registry defines local control at 6 months and describes a treatment schedule, it states that no data or specimens were collected. It also records termination due to poor accrual and reports no analyses. The listed enrollment is 1, but enrollment alone does not establish that an efficacy assessment was collected, that the treatment was delivered, or that follow-up for the endpoint occurred.
The trial was single-group, with no masking and no randomized comparator. Any outcome that might have been observed in such a design would describe the treated group; without a control group, it would not by itself estimate a causal difference from another treatment or from no treatment. In this case, the registry does not even report an efficacy outcome estimate, so there is no observed local-control result to interpret as a treatment effect or as a descriptive response frequency.
The endpoint definition combines complete response, partial response, and stable disease as local control. That composite classification includes disease that has not progressed as well as categories involving lesion disappearance or shrinkage. The definition gives a rule for classifying the treated site, but a rule is not an outcome. Without recorded assessments, the categories cannot be assigned and an event rate cannot be calculated from the registry record.
The registry lists secondary outcomes, including adverse events, time to local progression, 12-month local control, motion, pain, and tumor doubling times. It does not report analyses for these outcomes. Their inclusion in the study record should not be read as evidence that estimates were produced or that an outcome was observed. The adverse-event figures are separately recorded and should be read only as the registry's reported counts, with the limitations discussed for safety data.
No confidence interval, p-value, or other measure of efficacy uncertainty is reported for the primary endpoint. In general, a confidence interval describes a range of values compatible with the data and analysis under the method's assumptions. Here, the absence of a reported endpoint estimate means there is no interval to use in judging precision. It is not appropriate to interpret missing efficacy results as evidence either for benefit or for lack of benefit.
The planning illustrations use assumptions such as a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. These are planning conventions for hypothetical sample-size calculations, not a description of this single-group trial's observed analysis. Sample-size illustrations are not observed power, and they cannot supply the missing outcome data. The registry record does not report the trial's own sample-size justification or statistical analysis plan.
9. Statistical Methods Explained
The record describes a single-group phase II study, with allocation recorded as NA and masking as none. It reports no analyses. These design and reporting details determine what can be said statistically: the planned endpoint can be described, but there is no reported primary efficacy estimate to assess, and there is no randomized between-group contrast.
What does a single-group design estimate?
In general, a single-group study can describe outcomes among the people assessed after receiving the intervention. It does not provide a concurrent randomized comparison that separates the intervention's effect from other explanations for an outcome. Those explanations can include the natural course of disease, other care, selection of participants, and measurement practices. This is a general limitation of the design, not a claim that any one of those factors affected this study.
In this record, the limitation is more fundamental: no data or specimens were collected, and no analyses are reported. The record therefore does not provide a descriptive local-control estimate either. The enrollment entry does not substitute for an outcome observation, and it should not be treated as a denominator for an efficacy rate when the registry says no data were collected.
How should the local-control endpoint be understood?
In general, a binary endpoint reduces a more detailed clinical state to categories such as meeting or not meeting a prespecified definition. This study's local-control definition grouped complete response, partial response, and stable disease, while progression was defined by an interval increase in maximal dimension. The response definitions help determine how an assessment would be classified. They do not reveal the actual classification of any treated site.
The endpoint was specified at 6 months and applied to all treated sites of metastatic disease. In general, an endpoint tied to a fixed assessment time depends on having an assessment at that time or an analysis rule for unavailable assessments. The registry does not report the collection of endpoint data or the handling of missing assessments. It therefore does not establish whether any participant had an evaluable assessment at the target time.
What do uncertainty measures usually add?
In general, an estimate gives the observed value in a sample, while a confidence interval conveys the statistical uncertainty around that estimate under specified assumptions. A p-value, when used, evaluates compatibility between data and a stated null model; it does not measure the size or clinical importance of an effect. None of these quantities can be interpreted for the primary endpoint because no endpoint estimate or analysis is reported in the registry record.
The sample-size planning illustrations are based on generic planning assumptions: a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. For time-to-event planning, the description refers to the total number of events; for other planning, it refers to participants per arm. These hypothetical conventions do not match the reported single-group study design and should not be mistaken for the trial's original analysis plan. The record does not report the protocol's sample-size justification, and the illustrations are not observed power.
Why can over-dispersion matter in general?
In general, over-dispersion occurs when observed variability is greater than a statistical model expects. If a model assumes less variability than the data contain, uncertainty can be understated and inferential results can be too optimistic. This concept is relevant to some count and rate analyses, but the registry does not report an analysis of this kind for the trial. It is therefore a general statistical consideration, not a description of the methods used.
What does the analysis record establish?
The registry lists 7 outcome measures and 0 analyses. The outcome list documents topics that were specified for assessment, not a set of completed statistical results. The record does not report an analysis population, missing-data method, adjustment for multiple outcomes, interim analyses, or a detailed statistical analysis plan. Those omissions limit what can be reconstructed about the intended or performed analysis. They should not be filled in by assuming standard methods.
Overall, the statistical record supports a description of the design, endpoint definitions, and status, but not an efficacy inference. No recalculated estimate or comparison can replace the sponsor's own analysis if a discrepancy exists; in this record, no sponsor efficacy analysis is reported. The registry's absence of outcome data is the central constraint on statistical interpretation.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 7 outcome measures: the primary local-control endpoint at 6 months and secondary outcomes concerning adverse events, local progression, 12-month local control, motion, pain, and tumor doubling times. It reports 0 analyses. The presence of multiple planned outcomes raises a general multiplicity issue: when several hypotheses are tested, the chance of at least one apparently notable result can increase unless the testing strategy accounts for the number and relationship of analyses. The registry record does not report a multiplicity adjustment or a hierarchy for interpreting secondary outcomes.
The more immediate limitation is that no outcome data or specimens were collected, according to the record. No results are reported for the primary endpoint, and no analyses are listed. Thus, multiplicity adjustment cannot be evaluated as an applied procedure, and there are no reported outcome tests whose interpretation can be adjusted.
The record does not report an analysis population, rules for excluding participants or sites, or a method for handling missing outcome assessments. In general, a missing-data method describes how unavailable measurements are treated in analysis; it does not recover information that was never collected. Here, the statement that no data or specimens were collected precludes reconstructing endpoint assessments or an analysis population from the posted record. The protocol's detailed missing-data procedures are not reported in the registry record.
The registry's listed enrollment is 1, but it does not state that this entry represents an evaluable efficacy population. It would therefore be inappropriate to infer an analyzed denominator or calculate an endpoint rate from enrollment. The record also does not report whether any planned assessment or analysis was conducted before termination.
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 |
|---|---|---|---|
| Radiation Therapy in Metastatic Cancer | 0 | 1 | 0.0% |
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 |
|---|---|
| Radiation Therapy in Metastatic Cancer | 1 of 1 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Radiation Therapy in Metastatic Cancer |
|---|---|---|
| Pain::Buttock | Musculoskeletal and connective tissue disorders | 1 of 1 |
| Diarrhea | Gastrointestinal disorders | 1 of 1 |
| Pneumonitis/pulmonary infiltrates | Respiratory, thoracic and mediastinal disorders | 1 of 1 |
| Urinary retention (including neurogenic bladder) | Renal and urinary disorders | 1 of 1 |
| Weight loss | General disorders | 1 of 1 |
| Dermatology/Skin - Other (Specify) | Skin and subcutaneous tissue disorders | 1 of 1 |
| Anorexia | Gastrointestinal disorders | 1 of 1 |
| Fatigue (asthenia, lethargy, malaise) | General disorders | 1 of 1 |
| Taste alteration (dysgeusia) | Gastrointestinal disorders | 1 of 1 |
| Pain::Extremity-limb | Musculoskeletal and connective tissue disorders | 1 of 1 |
The registry's adverse-event figures list the Radiation Therapy in Metastatic Cancer group with 1 at risk for serious adverse events and 0 affected. For other adverse events, it lists 1 at risk and 1 affected. These are the posted counts and should be read as registry entries, not as a complete safety profile.
The figures do not establish the nature, severity, timing, duration, or relatedness of the reported other adverse event. The registry lists no serious adverse-event terms. It does not report a cause for the other event, and these counts alone cannot show whether an event was related to radiation or to other care. The record does not provide additional details that would clarify exposure or the circumstances of event collection.
The study is recorded as terminated due to poor accrual, and the record states that no data or specimens were collected. The adverse-event entries should not be used to infer that a comprehensive safety analysis was completed. Counts from a small recorded risk set are highly limited descriptions; they do not establish the frequency of events in a broader population or provide a reliable comparison with another treatment.
In general, safety counts require context about how events were defined, elicited, graded, and followed. The registry record does not report those details. The appropriate reading is therefore limited to the recorded at-risk and affected counts, without inferring a causal relationship or drawing a general safety conclusion.
12. What the Result Does, and Does Not, Mean
The record establishes that a phase II, single-group study of hypofractionated, highly conformal radiation with helical tomotherapy was planned for metastatic cancer outside the brain. It specifies a treatment schedule and defines local control at 6 months as complete response, partial response, or stable disease. It also lists several secondary outcomes. These details describe the study's intended questions and intervention framework.
The registry does not establish an efficacy result. It states that no data or specimens were collected, lists 0 analyses, and says the study was terminated due to poor accrual. No observed local-control estimate, uncertainty interval, or comparison with another treatment is reported. Accordingly, the record cannot support a conclusion that the intervention improved local control, failed to improve it, or differed from another approach.
Even if an outcome estimate had been available, the single-group design would have limited causal interpretation because there was no randomized comparator. In general, a treated-group outcome can be described, but it does not by itself distinguish an intervention effect from other influences on outcome. In this case, the absence of collected outcome data means that even a descriptive efficacy estimate is unavailable.
The adverse-event counts provide a narrow safety description, not a full account of harms. The registry reports 0 serious adverse events among 1 at risk and 1 other adverse event among 1 at risk. It does not provide event details or establish causality. These entries should not be taken as evidence of a comprehensive safety evaluation or generalized beyond the record.
The sample-size planning illustrations are not trial results and are not observed power. They cannot repair the lack of outcome data or demonstrate that the study could answer its efficacy question. The registry record does not report the original sample-size justification or detailed statistical plan. The main meaning of the posted information is therefore about the study's design and its incomplete outcome record, rather than about the clinical effect of radiation.
13. Why This Trial Matters Statistically
This study matters statistically because it illustrates the difference between a prespecified endpoint and an observed result. The registry gives a clear primary endpoint definition: local control at 6 months, combining complete response, partial response, and stable disease. But it also states that no data or specimens were collected. A detailed endpoint definition cannot generate an estimate when the assessments needed to classify outcomes are absent.
The record also makes clear why enrollment, accrual, and analysis are not interchangeable. Enrollment is recorded as 1, while termination is attributed to poor accrual. Yet enrollment does not show that an endpoint was assessed, and the record reports no analyses. Statistical interpretation must follow the outcome data and analysis actually reported, rather than treating design intentions or a registry enrollment entry as completed evidence.
The single-group structure is another important feature. In general, a study without a randomized comparator can describe outcomes in its treated group, but it cannot directly estimate a randomized treatment contrast. That limitation would remain even if results were available. Here, no primary efficacy outcome is reported, so neither a comparative effect nor a treated-group local-control estimate can be assessed.
Finally, the listed secondary outcomes and planning assumptions illustrate the distinction between planned measurement and reported analysis. The registry lists several outcomes but reports 0 analyses. Generic sample-size conventions are not a record of the trial's own statistical plan and are not observed power. Readers can identify the questions the study intended to address, while also recognizing that the posted record does not answer them with outcome data.
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 central limitation is that the registry states no data or specimens were collected. It reports no primary endpoint result and lists 0 analyses. Thus, there is no local-control estimate at 6 months, no reported measure of precision, and no basis for evaluating response classifications or time-to-event outcomes from the posted record.
The study was terminated due to poor accrual, and enrollment is recorded as 1. The registry does not report whether that enrollment resulted in treatment delivery or endpoint assessment. It also does not describe the reasons for poor accrual beyond that statement. No additional explanation should be inferred.
The single-group design and absence of masking limit the kinds of comparisons that could be made even if outcomes were available. Allocation is recorded as NA, and no like-for-like control group is identified. The record therefore does not permit a randomized treatment comparison. The protocol's detailed statistical plan, sample-size justification, analysis population, interim-analysis procedures, multiplicity strategy, and missing-data methods are not reported in the registry record.
The endpoint depends on classification of treated lesions using specified response criteria, but the record does not provide assessment schedules beyond the stated primary time point, measurement procedures, or rules for missing assessments. The secondary outcomes are listed without reported analyses. This leaves the intended measurement framework more complete than the available statistical evidence.
The adverse-event entries are limited to the at-risk and affected counts. Event descriptions, grading, timing, relatedness, and follow-up details are not reported. Taken together, these limitations mean the registry supports a description of planned design and the reason for termination, but not a clinical efficacy conclusion or a comprehensive safety assessment.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Conformal Radiation Therapy in Treating Patients With Metastatic Cancer Outside the Brain — NCT00550654.
- Registry record last updated 2017-01-13; status last verified 2016-11.
- Results first posted 2012-09-18.
- 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
This phase II study evaluated planned hypofractionated, highly conformal radiation with helical tomotherapy for metastatic cancer outside the brain. It was a single-group study with no masking and no randomized comparator. The treatment description specified delivery once every other day over 5 days, for a total of 3 fractions.
The primary endpoint was local control at 6 months, defined as complete response, partial response, or stable disease at treated sites. Enrollment is recorded as 1. The study started in 2007-10, had a primary completion date of 2010-05, and is listed as terminated due to poor accrual.
The registry states that no data or specimens were collected and lists 0 analyses. It therefore provides no primary efficacy result. The recorded adverse-event counts are limited and do not constitute a comprehensive safety analysis.