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 Stereotactic Radiation Therapy for Pediatric Sarcomas (NCT01763970), a na na study. The primary outcome is Lesion-specific Local Control at 6 Months Post-SBRT as Assessed by Percentage of Lesions Locally Controlled.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01763970 |
| Phase | NA |
| Condition | Sarcoma, Metastatic Disease, Bony Sites |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 14 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns pediatric patients with metastatic sarcomas of bony sites. The registry record reports enrollment of 14 participants. It does not report the age range, detailed eligibility criteria, or the number of lesions treated per participant. The background discusses patients with limited metastases, but the registry record does not establish that every enrolled participant met a particular definition of limited metastatic disease.
Intervention
The intervention was stereotactic body radiation therapy (SBRT), described in the arm as hypofractionated SBRT. The regimen is listed as 800 cGy delivered in 5 fractions every day, to a total dose of 4000 cGy. The intervention type is radiation. The registry record does not provide further information about treatment planning, delivery, or any additional care.
Comparator
There was no separate comparator arm: the study is listed as single-group, with allocation recorded as NA and masking as none. Consequently, the registry record does not describe a randomized or concurrent control comparison. Outcomes can be described for participants or lesions in the treated group, but the design does not directly estimate how outcomes would differ under another treatment.
Primary question
The primary question concerns the percentage of lesions locally controlled at 6 months post-SBRT. Local control was defined as absence of local progression under specified imaging and lesion criteria. This is a lesion-level outcome, rather than a percentage of participants with control. The registry record does not report the primary percentage, its 95% confidence interval, or the number of lesions contributing to the estimate, so the magnitude and precision of the primary result cannot be assessed from the registry record.
3. Trial Design
This was a completed phase II study recorded under the title “A Phase II Study of Hyperfractionated Stereotactic Radiotherapy in the Treatment of Metastatic Pediatric Sarcomas of Bony Sites.” The registry identifies the study population as pediatric patients with metastatic sarcomas of bony sites and lists an enrollment of 14. The study began in 2013-11, reached primary completion on 2018-09-24, and is marked completed. The listed phase is NA.
The design is single-group. Allocation is recorded as NA and masking as none. There is one intervention group, Hypofractionated SBRT, and no control group. The regimen is described as 800 cGy delivered in 5 fractions every day to a total dose of 4000 cGy. Because there is no separate comparison arm, the study design is suited to describing outcomes within the treated group, not to making a randomized comparison with another treatment or with no treatment.
The registry lists 8 outcome measures. Secondary outcomes include patient-specific local control at 6 months, progression-free survival at 6 months, overall survival at 6 months, change in quality of life assessed by the Brief Pain Inventory, and the number of participants experiencing SBRT toxicity. The primary endpoint is instead lesion-specific local control at 6 months. These distinctions matter: participant-level outcomes and lesion-level outcomes use different units, and one participant may have more than one lesion. The number of treated lesions is not reported in the registry record.
The registry record does not report detailed eligibility criteria, the analysis populations, a sample-size justification, interim analyses, or a statistical analysis plan. Although the study is marked completed, that status alone does not establish that every planned outcome was analyzed or reported.
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 | Hypofractionated SBRT |
|---|---|
| STARTED | 14 |
| COMPLETED | 14 |
| 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.
| Characteristic | Unit | Hypofractionated SBRT |
|---|---|---|
| Participants analysed | 14 | |
| Age, Continuous | years | 17 (4 to 25) |
| Sex: Female, Male: Female | Participants | 5 |
| Sex: Female, Male: Male | Participants | 9 |
| Race/Ethnicity, Customized: Caucasian | Participants | 9 |
| Race/Ethnicity, Customized: Non-Caucasian | Participants | 5 |
| Region of Enrollment: United States | Participants | 14 |
| Lansky Play-Performance Scale (LPS) for Pediatric Functional Status: LPS = 100 | Participants | 3 |
| Lansky Play-Performance Scale (LPS) for Pediatric Functional Status: LPS = 80-90 | Participants | 10 |
| Lansky Play-Performance Scale (LPS) for Pediatric Functional Status: LPS = 70 | Participants | 1 |
| Lansky Play-Performance Scale (LPS) for Pediatric Functional Status: LPS < 70 | Participants | 0 |
| Histological type of cancer: Ewing sarcoma | Participants | 7 |
| Histological type of cancer: Osteosarcoma | Participants | 3 |
| Histological type of cancer: Soft-tissue sarcoma | Participants | 4 |
| Number of Lesions Treated in Each Patient | lesions | 2.5 (1 to 5) |
| Consolidation of Metastatic Disease: Total | Participants | 8 |
| Consolidation of Metastatic Disease: Partial | Participants | 6 |
| Prior systemic therapy | Participants | 14 |
| Pain at baseline: Yes, has pain | Participants | 6 |
| Pain at baseline: No pain | Participants | 8 |
| Treatment Duration | days | 7 (5 to 15) |
6. Primary Endpoint
The registry lists the primary outcome as Lesion-specific Local Control at 6 Months Post-SBRT as Assessed by Percentage of Lesions Locally Controlled, measured over 6 months post-SBRT.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage of lesions |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the percentage of lesions locally controlled at 6 months post-SBRT. The unit is percentage of lesions, making this a lesion-specific measure rather than a patient-level measure. Local control is defined as absence of local progression. The registry defines progression through lesion-specific changes: a new soft tissue mass at a site with no soft tissue component or with a soft tissue component smaller than 1 cm at baseline; an increase of more than 20% in the largest axial dimension for lesions with a soft tissue component of at least 1 cm at baseline; or renewed FDG-PET avidity in a previously avid bone metastasis that became non-avid after SBRT.
A local-control endpoint focuses on change at the treated site. The registry’s definitions combine structural change in soft tissue and metabolic imaging change for a bone metastasis. That operational definition is important because the outcome depends on how progression is classified, not simply on whether a lesion remains visible. The registry states that the Kaplan-Meier method was used, but does not explain how censoring or any competing events were handled.
The registry record does not report the estimated percentage of lesions locally controlled, its 95% confidence interval, the number of lesions assessed, or the number of progression events. Without those results, the endpoint’s observed magnitude and precision cannot be described. The rationale for the endpoint is to quantify control at the treated lesion, while the separately listed patient-level outcomes address broader clinical status.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a primary endpoint and a method, but does not include the primary endpoint result. In particular, the percentage of lesions locally controlled at 6 months and its 95% confidence interval are not reported in the registry record. The number of lesions included in the analysis and the number classified as locally progressed are also not reported. Therefore, neither the observed level of local control nor the precision of that estimate can be evaluated from the record.
The endpoint is lesion-specific, while enrollment is reported as 14 participants. These are different units of analysis. Participant enrollment alone does not indicate how many lesions were treated or analyzed, and it should not be treated as the denominator for a lesion-level percentage. The registry record does not report whether participants contributed different numbers of lesions or how any within-participant dependence was handled. If multiple lesions from one person were analyzed, treating each lesion as independent could understate uncertainty; whether this issue arose or how it was addressed is not reported in the registry record.
The study’s single-group design supports descriptive statements about outcomes in the treated group if outcome data are reported. It does not provide a contemporaneous control group for estimating a treatment contrast. The registry also lists allocation as NA and masking as none. These design features do not establish a comparison with usual care, another radiation approach, or an untreated group. Any differences from external experience would require information and assumptions beyond the registry record.
The registry lists secondary outcomes at 6 months for patient-specific local control, progression-free survival, and overall survival, along with quality-of-life change and toxicity. Their results are not reported in the registry record. Nor does the record provide estimates for time-to-event outcomes, the timing of assessments, or details about the handling of incomplete follow-up. The study status is completed, but completion status is not itself an outcome result.
The safety counts describe participants with serious adverse events, other adverse events, and deaths in the listed group. They do not establish that an event was caused by SBRT. The record does not give event timing, severity grading beyond the serious/non-serious grouping, participant-level overlap between categories, or the relationship of deaths to treatment. The reported percentages for the top serious-event terms should be read as registry entries, not as estimates of comparative risk.
The record also includes assumptions for planning illustrations based on an observed effect, but does not report the underlying primary endpoint estimate or numerical planning results in the registry record for this analysis. Such illustrations are not observed power and do not substitute for the study’s outcome estimates. The registry record does not report a sample-size justification for the trial itself. Overall, the registered design and endpoint can be described, but a quantitative efficacy interpretation is not possible from the outcome information reported.
9. Statistical Methods Explained
What does the Kaplan-Meier method contribute?
Kaplan-Meier is a method for estimating the pattern of time to an event when participants or observations may have different lengths of follow-up. Rather than requiring every observation to have the event recorded at the same fixed time, the method can incorporate observations whose follow-up ends before an event is seen, under assumptions about censoring. The registry states that Kaplan-Meier was used for the primary endpoint. It does not report the event-time data, the number of events, the number censored, or the details of censoring, so the estimate cannot be reconstructed or its assumptions checked from the registry record.
The endpoint is defined as the percentage of lesions locally controlled at 6 months. The record does not explain how the Kaplan-Meier estimate was translated into that percentage, how lesions were represented in the analysis, or how dependence among lesions from the same participant was handled. These are relevant because the registered unit is lesions, while the enrolled units are participants. The actual analysis method for any clustering or multiple lesions per participant is not reported in the registry record.
What does a 95% confidence interval mean?
A confidence interval expresses uncertainty around an estimated quantity under the assumptions of the method used. It helps distinguish a result estimated with relatively high precision from one that remains compatible with a broader range of values. It does not guarantee that the true value lies within a particular interval, and it does not by itself show whether a result is clinically important. The registry specifies 95% confidence interval as the dispersion measure for the primary endpoint, but the interval’s bounds are not reported in the registry record. Without the estimate and interval, no assessment of precision is possible.
Why does the study design matter?
A single-group study has no concurrent control arm. As a result, an outcome observed after SBRT cannot be directly contrasted with an outcome under a different assigned treatment within this study. The registry records allocation as NA and masking as none, consistent with the absence of a randomized comparison. Descriptive outcome estimates, if available, would characterize the treated group; they would not by themselves distinguish treatment effects from other explanations such as participant characteristics, disease course, assessment practices, or subsequent care. The record does not report procedures that would support a causal comparison.
The lesion-level endpoint also requires care in interpreting uncertainty. If one participant contributes multiple lesions, those lesions may share participant characteristics and are not necessarily statistically independent. General statistical methods can account for clustered observations, but the registry record does not state whether such methods were used. The number of lesions and the analysis details are not reported, so the potential importance of this issue cannot be quantified.
How should the planning illustrations be understood?
The planning assumptions describe an illustrative calculation based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. For time-to-event calculations, the planning quantity is the total number of events; for other calculations, it is participants per arm. These are planning illustrations, not observed trial outcomes, and not observed power. They do not mean the single-group study enrolled those numbers per arm, since the registered study has one group and enrollment of 14.
A planning calculation depends on its assumptions and on the effect used as its reference. If an observed effect is uncertain, planning values based on it inherit that uncertainty. The registry record does not report a trial-specific sample-size justification or a numerical primary endpoint result in the registry record for this analysis. It is therefore not possible to assess whether the study’s enrollment was selected to achieve a specified precision or power, or to reproduce the planning illustrations. No interim-analysis approach or multiplicity adjustment is reported in the registry record.
More generally, over-dispersion means that variability in observed outcomes exceeds what a chosen statistical model expects. In such settings, a model that ignores the extra variability can produce confidence intervals that are too narrow and tests that are too optimistic. This is a general statistical consideration, not a claim that over-dispersion occurred in this study. The registry record does not report an over-dispersion assessment or a model for the primary endpoint.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 8 outcome measures, including the primary lesion-specific local-control endpoint and secondary participant-level outcomes. When a study examines several outcomes, the chance of at least one apparently notable result can increase if each is tested separately without accounting for multiplicity. Different outcome types may also answer distinct questions, so the appropriate approach depends on which outcomes were prespecified as primary or secondary and how the analyses were structured. The registry record does not report a multiplicity strategy, hierarchy among secondary outcomes, or adjustment procedure.
The record does not report whether interim analyses were planned or performed. It also does not describe a statistical analysis plan, including any rules for choosing analysis populations or handling deviations from the intended treatment. These details are important for interpreting whether analyses followed prespecified procedures, but they are not reported in the registry record.
Missing-data handling is also not reported in the registry record. For the 6-month endpoints, the record does not specify how participants or lesions without an assessment at that time were treated, how loss to follow-up was handled, or whether missingness differed across outcomes. For the time-to-event method, censoring details are not reported. A completed study status does not establish that all outcome data were complete.
The registry does not report the analysis population for the primary endpoint, the number of participants or lesions included in each outcome analysis, or any exclusions from analysis. These omissions limit assessment of the denominator, potential selection after enrollment, and consistency between the enrolled group and the analyzed group. Consequently, multiplicity, missingness, and population-selection effects cannot be evaluated from the registry record.
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 |
|---|---|---|---|
| Hypofractionated SBRT | 2 | 14 | 14.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Hypofractionated SBRT | 8 of 14 |
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 |
|---|---|
| Hypofractionated SBRT | 8 of 14 |
Most frequent serious adverse event terms
| Event term | Organ system | Hypofractionated SBRT |
|---|---|---|
| Esophagitis | Gastrointestinal disorders | 1 of 14 |
| Soft tissue necrosis and fracture | Musculoskeletal and connective tissue disorders | 1 of 14 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Hypofractionated SBRT |
|---|---|---|
| Back Pain | Musculoskeletal and connective tissue disorders | 3 of 14 |
| Fatigue | General disorders | 2 of 14 |
| alopecia | Skin and subcutaneous tissue disorders | 1 of 14 |
| nasal congestion | Respiratory, thoracic and mediastinal disorders | 1 of 14 |
| myositis | Musculoskeletal and connective tissue disorders | 1 of 14 |
| Lower Extremity Weakness | Nervous system disorders | 1 of 14 |
| Wrist Pain | Musculoskeletal and connective tissue disorders | 1 of 14 |
| Skin Hyperpigmentation | Skin and subcutaneous tissue disorders | 1 of 14 |
| Compression Fracture | Musculoskeletal and connective tissue disorders | 1 of 14 |
| Paresthesia of the lower extremity | Nervous system disorders | 1 of 14 |
Serious events with the highest arm-level rate: esophagitis (7.1%), soft tissue necrosis and fracture (7.1%).
The registry lists 14 participants at risk for serious adverse events and 2 participants affected. It separately lists 14 at risk for other adverse events and 8 affected. These are participant counts for the Hypofractionated SBRT group. The registry also lists 8 deaths. The record does not state that these deaths were caused by SBRT, nor does it provide timing or cause of death in the information.
The top serious adverse-event terms are Esophagitis and Soft tissue necrosis and fracture, each listed as 7.1%. Those entries describe the registry’s reported terms and percentages; they do not show whether the same participant experienced more than one term, or whether events occurred in the same participant as other adverse events. The record does not provide detailed event-level counts, timing, duration, resolution, or severity grading beyond the serious-event classification.
Serious adverse events and other adverse events are separate registry categories, but the available information does not describe overlap between them. The counts should not be added to create a total number of affected participants. Nor do these figures provide a comparative risk estimate, because the study has one group and no control arm. The safety data describe reported events in this group; they do not establish attribution to treatment or a causal relationship.
12. What the Result Does, and Does Not, Mean
The record establishes that a completed, single-group study evaluated hypofractionated SBRT for metastatic pediatric sarcomas of bony sites, with lesion-specific local control at 6 months as the primary endpoint. It also gives the endpoint definition, describes the treatment regimen, lists secondary outcomes, and reports selected participant-level safety counts. These registry entries help clarify what the study was intended to measure and how its registered design was structured.
However, the primary percentage of lesions locally controlled and its 95% confidence interval are not reported in the registry record. The number of lesions analyzed is also not reported. Accordingly, the registry information does not establish the observed local-control result or how precisely it was estimated. The listed secondary outcomes do not have reported results in the information available for this analysis, so no conclusions about their observed values can be drawn either.
The single-group design does not provide a direct comparison against another treatment or a control condition. Even if a within-group outcome estimate were available, it would describe outcomes among the studied group and would not alone establish what would have happened to comparable participants under another approach. The registry record does not report a randomized comparison or an analysis intended to estimate a treatment contrast.
The reported adverse-event counts and deaths should be read as descriptive registry entries, without assuming causation or a treatment-related explanation. The information does not establish how events were timed, whether categories overlapped, or why deaths occurred. Likewise, enrollment of 14 participants does not reveal the number of lesions analyzed or the amount of follow-up contributing to each endpoint.
Thus, the registry record supports a description of study design, treatment, endpoint definitions, and selected safety counts. It does not support a quantitative judgment about the primary endpoint’s magnitude, its precision, comparative effects, or the reasons for the safety outcomes. Those distinctions are necessary when separating what the registered study measured from what its reported data can establish.
13. Why This Trial Matters Statistically
This study illustrates why the unit of an endpoint matters. Enrollment is reported as 14 participants, while the primary outcome is the percentage of lesions locally controlled. A participant-based denominator cannot be substituted for a lesion-based denominator, and the registry does not report the lesion count. When several lesions can belong to one participant, the analysis may also need to account for shared characteristics. Whether the study did so is not reported in the registry record.
It also illustrates the difference between a named endpoint and a reported result. The record defines local progression in detail and specifies a 95% confidence interval and Kaplan-Meier method, yet it does not report the estimated percentage or interval. A reader can understand the intended measurement without being able to assess the outcome’s magnitude or precision. Study completion does not fill that reporting gap.
The design further shapes the conclusions available. With one group and no comparator, the analysis is descriptive rather than a direct treatment comparison. Safety counts can identify what the registry lists for the group, but they cannot establish attribution or comparative risk. This distinction is especially important when a record includes both adverse events and deaths without event timing or causal assessment.
Finally, planning illustrations and trial results serve different purposes. Assumptions such as equal allocation and a specified significance level can generate planning quantities, but those quantities are not outcomes observed in the trial and are not observed power. The registry record does not report a trial-specific sample-size justification. Separating design planning, endpoint definitions, and observed results is essential for a statistically accurate account of a clinical study.
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 principal limitation for interpreting this study from the registry record is the absence of the primary endpoint estimate and confidence interval. The number of lesions assessed, the number of local progressions, and the analytic denominator are also not reported. This prevents evaluation of both the observed local-control level and its precision.
The primary outcome is lesion-specific, but enrollment is expressed as participants. The registry record does not describe the number of lesions per participant or the statistical treatment of multiple lesions from one person. It also does not report how censoring was handled for the stated Kaplan-Meier method, or whether any competing events were considered. These details limit assessment of the method and uncertainty.
The single-group design has no concurrent comparator, so it cannot directly estimate differences between SBRT and another treatment. The registry lists no masking and allocation as NA. The record does not report detailed eligibility criteria, participant characteristics, disease burden, follow-up completeness, or treatment delivery details beyond the stated regimen. These omissions make it difficult to assess how broadly the group might represent other patients or settings.
Outcome reporting is incomplete in the information available: results for the listed secondary outcomes are not reported in the registry record. The record also does not describe missing-data methods, analysis populations, multiplicity procedures, interim analyses, or a statistical analysis plan. Safety counts lack event timing and attribution details. These limitations do not show that such procedures or information were absent from all study documentation; they mean they are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Stereotactic Radiation Therapy for Pediatric Sarcomas — NCT01763970.
- Registry record last updated 2020-08-27; status last verified 2020-08.
- Results first posted 2020-08-27.
- 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
NCT01763970 is a completed single-group phase II study of hypofractionated SBRT for metastatic pediatric sarcomas of bony sites. The registry lists enrollment of 14 participants, allocation as NA, and masking as none. The regimen is 800 cGy delivered in 5 fractions every day to a total dose of 4000 cGy.
The primary endpoint is the percentage of lesions locally controlled at 6 months post-SBRT, with local control defined as absence of local progression. The registry states that the Kaplan-Meier method was used and identifies a 95% confidence interval as the dispersion measure. The primary estimate, confidence interval, and lesion count are not reported in the registry record.
Listed safety counts include 2 participants with serious adverse events, 8 with other adverse events, and 8 deaths. The record does not establish treatment causation. Detailed analysis populations, missing-data handling, multiplicity procedures, and a trial-specific sample-size justification are not reported in the registry record.