Surgery and/or Chemotherapy in Treating Children With Infantile, Congenital, or Childhood Fibrosarcoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Surgery and/or Chemotherapy in Treating Children With Infantile, Congenital, or Childhood Fibrosarcoma (NCT00072280), a non-randomized phase 2 study. The primary outcome is Failure-free Survival (FFS) in "Chemotherapy Plus Possible Surgery" Arm.

2. Clinical Question

The study focused on children with fibrosarcoma and examined treatment pathways involving surgery, combination chemotherapy, or both. The registry describes a phase II pilot study, with enrollment of 7. The primary endpoint was failure-free survival in the chemotherapy-plus-possible-surgery arm, rather than a randomized comparison of the two arms.

The clinical question is therefore about the recorded status of eligible patients in that arm over follow-up, using the registry’s definition of failure. That definition includes disease progression, relapse after response, or death as a first event. The registry does not report the counts in the endpoint categories, so the observed failure-free survival results cannot be described from this record.

The surgery-only arm provides context about a different treatment pathway, but not a randomized control group. Patients entered that arm based on initially resectable disease; the chemotherapy arm included patients whose disease was initially unresectable or whose resection left grossly positive margins. Those differences in eligibility and disease characteristics limit direct interpretation of any arm-to-arm contrast.

3. Trial Design

The registry describes a pilot phase II study with non-randomized allocation, no masking, and a parallel model. The study was sponsored by Children's Oncology Group. Enrollment was 7. The recorded start was 2004-11, primary completion was 2008-03, and status is terminated. The reason for termination is not reported in the registry record.

Rather than assigning participants at random to comparable treatment groups, the protocol descriptions placed patients in arms according to disease resectability and surgical margins. The chemotherapy-plus-possible-surgery arm comprised patients with initially unresectable lesions, or lesions resected with grossly positive margins. The description says all patients in this arm received vincristine sulfate, dactinomycin, cyclophosphamide, and MESNA; surgery could follow depending on response. The remainder of that arm description is incomplete in the registry record, so further treatment details are not reported in the registry record.

The surgery-only arm comprised patients with initially resectable disease. Patients underwent conventional surgery, and those with clear or microscopically positive margins remained under observation without further intervention, according to the arm description.

This design is useful to describe the treatment pathways and outcomes recorded for the patients in each pathway. It does not support interpreting the arms as randomized alternatives: treatment assignment was related to resectability and margins, which may also relate to prognosis. The record does not report a randomization procedure, a masking procedure beyond none, or a statistical plan for comparing arms.

The record identifies a primary completion date and a terminated status but does not explain the termination or give a final follow-up date. The endpoint description states that results are through March 2008 and refers to a caveat, but details of that caveat 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.

Treatment

Reasons for not completing this period:

Follow-up

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: By protocol design, only eligible patients were considered in the evaluation for the primary outcome measure. One (1) patient was found ineligible, leaving two (2) for the analysis population.

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.

6. Primary Endpoint

The registry lists the primary outcome as Failure-free Survival (FFS) in "Chemotherapy Plus Possible Surgery" Arm, measured over Study enrollment until failure, completion of follow-up, or completion of 5-year FFS analyses (up to 5 years).

The primary endpoint is failure-free survival in the chemotherapy-plus-possible-surgery arm. The registry defines failure as disease progression, relapse after response, or death as the first event. Progression is defined as at least a 20% increase in disease measurement relative to the smallest measurement recorded since treatment began, or the appearance of one or more new lesions. Relapse uses the same criteria as progression after a response.

The registry planned to classify eligible patients at the data cutoff for the 5-year failure-free survival analyses as failed, failure-free through 5 years of follow-up, failure-free until cutoff with less than 5 years of follow-up, withdrawn, or lost to follow-up. The endpoint description gives the observation period as enrollment until failure, completion of follow-up, or completion of the 5-year analyses.

Failure-free survival is used to capture whether a defined event has occurred over follow-up, rather than describing tumor response alone. It can include progression, relapse, or death, each of which is relevant to the endpoint’s stated definition. In general, time-to-event endpoints can also account for participants whose event has not been observed by the end of their available follow-up. The registry’s categories distinguish patients with follow-up through 5 years from those who were failure-free only until an earlier cutoff.

The record gives the endpoint definition and the analysis population, but not the observed counts by category or an estimated failure-free survival curve. Thus, the endpoint’s clinical meaning can be described, but its observed result cannot be quantified from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The endpoint is named failure-free survival, but the registry’s stated reporting format is a count of eligible patients in outcome categories at data cutoff. The record does not report a survival curve, a hazard ratio, a median, or an estimated probability of remaining failure-free. It also does not report the statistical method used to analyze the endpoint. Those methods should not be inferred from the endpoint name alone.

What does failure-free survival represent?

In general, a time-to-event endpoint records the time until a defined event occurs. Here, the event definition includes progression, relapse after response, or death as a first event. This composite definition means that any one of the listed events can count as failure. A composite endpoint can summarize several clinically relevant outcomes, but its interpretation depends on the components and their definitions. The registry provides those definitions, but does not report the number of failures attributable to each component.

The stated categories also distinguish people with complete follow-up through 5 years from people who were failure-free until the data cutoff but had less than 5 years of observation. This distinction matters because not observing failure during shorter follow-up does not establish that failure would remain absent through the full follow-up period. In general, time-to-event methods can use partial follow-up while recognizing that the event time is not known beyond the last observed time. The registry does not report whether, or how, such methods were used.

What does the endpoint count tell the reader?

A count by outcome category would describe the number of eligible patients assigned to each status at the stated cutoff. It would not, by itself, show the timing of failures or provide a measure of uncertainty around an estimated survival probability. The category counts themselves are not reported in the registry record, so no event proportion or failure-free survival estimate can be interpreted.

For a statistical estimate, a confidence interval describes the range of values reasonably compatible with the observed data under the method’s assumptions. It communicates precision as well as the point estimate. No confidence interval is reported for this endpoint, and there is no estimate from which to assess precision. General explanations of confidence intervals cannot substitute for a missing trial result.

What can be inferred from the design?

Non-randomized allocation means that the arms were not formed by chance assignment. The registry describes one arm for initially unresectable disease or grossly positive margins and another for initially resectable disease. In general, such baseline differences can confound comparisons: an observed difference might reflect patient or disease characteristics, treatment, or both. Randomization is one way to balance factors on average, but it was not used in this study. The record does not report an adjustment strategy that would address differences between the arms.

The parallel model means the registry describes separate groups following different treatment pathways. It does not make those groups exchangeable for comparison. The record is unmasked, and does not report a blinding procedure. The registry also does not report the statistical plan, including how any comparisons or uncertainty estimates were intended to be handled.

How should the planning illustration be understood?

The registry’s planning assumptions describe an illustration based on an observed effect, not the original trial design. The stated assumptions are a two-sided significance level of 0.05, equal allocation between arms, a normal approximation, and detection of a stated fraction of the observed effect. The record specifies that time-to-event illustrations use total events and other illustrations use participants per arm. These are planning conventions, not observed trial results or observed power. The registry does not report the original sample-size justification or a protocol-based sample-size target.

A sample-size illustration estimates the amount of information that a hypothetical future study might need under its assumptions. It does not establish that this study had adequate power, and it cannot recover missing endpoint results. The actual allocation was non-randomized, so the illustration’s equal-allocation assumption does not describe how participants entered the study. Any planning estimate also depends on the effect used and the model assumptions; the registry does not report enough information to evaluate those assumptions independently.

What methods remain unknown?

The statistical analysis plan, handling of censoring, approach to missing outcome data, confidence-interval method, and any interim analyses are not reported in the registry record. Nor are individual follow-up times, endpoint category counts, or the analysis output. Without those details, the statistical precision and robustness of the primary endpoint cannot be assessed. The appropriate reading is therefore descriptive: the registry specifies an endpoint and its criteria, but does not post the primary analysis results needed to quantify it.

10. Multiplicity, Missing Data and Analysis Populations

The registry identifies one primary outcome measure, failure-free survival in the chemotherapy-plus-possible-surgery arm. It records 0 analyses. This entry does not establish whether an analysis was not performed, was not entered, or is absent for another reason. The statistical plan and any interim analyses are not reported in the registry record.

Multiplicity concerns can arise when many outcomes, comparisons, subgroups, or repeated analyses are examined. In general, conducting many statistical tests can increase the chance of finding an apparently notable result by chance. The registry does not report a multiplicity adjustment or describe a broader testing strategy. With no p-values or inferential results posted, there is no basis for assessing how multiplicity was handled in any analysis.

The primary endpoint population was restricted to eligible patients. The record states that one (1) patient was ineligible, leaving two (2) for the analysis population. It does not report the specific eligibility reason or a complete participant flow by arm. The endpoint categories include withdrawal and loss to follow-up, but the counts in those categories are not reported in the registry record.

In general, missing outcome information can affect interpretation if the likelihood of missingness is related to a patient’s outcome or condition. The registry does not report a missing-data method, rules for censoring, or sensitivity analyses. It is therefore not possible to determine how incomplete follow-up was handled or whether any assumptions about missing outcomes were tested. The absence of those details should not be interpreted as evidence that no participants had missing data.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists serious adverse events for two arms. In the chemotherapy-plus-possible-surgery arm, 2 participants were at risk and 0 were affected by a serious adverse event. In the surgery-only arm, 2 participants were at risk and 0 were affected. No serious adverse event terms are listed.

For other adverse events, the registry lists 2 participants at risk in each arm. One participant in the chemotherapy-plus-possible-surgery arm was affected, and 0 in the surgery-only arm were affected. These counts indicate the number of participants recorded as affected, not the number of separate events. The registry does not provide the event descriptions, severity breakdown, or timing in the registry record recorded for these figures.

The deaths field is not reported for either group; it should not be read as a count of zero. The small listed at-risk groups and the absence of detailed event information limit interpretation. These descriptive counts do not establish that a treatment caused or prevented an adverse event, and the non-randomized arms should not be compared as if they were equivalent groups.

12. What the Result Does, and Does Not, Mean

The registry record establishes the study’s intended clinical question, treatment pathways, endpoint definition, and some safety counts. It does not provide the primary endpoint category counts or an inferential analysis. As a result, the central outcome cannot be summarized as a failure-free survival estimate, and no statement about the size or precision of an observed treatment effect is supported by this record.

The reported analysis population for the primary outcome is two (2) eligible patients in the chemotherapy-plus-possible-surgery arm. That population is distinct from the overall enrollment figure of 7. The record does not give enough participant-flow detail to account for the full enrollment or to describe the endpoint status of each person.

The safety entries report no serious adverse events among the listed participants at risk, alongside one participant with another adverse event in the chemotherapy-plus-possible-surgery arm and none in the surgery-only arm. These small descriptive counts cannot establish that either pathway is safer. The deaths entries are not reported, and the registry does not supply event-level details that would permit a fuller safety assessment.

The study was non-randomized, with treatment pathway related to disease resectability and surgical margins. Therefore, the arms do not function as comparable controls. Even if arm-level outcome estimates were available, unadjusted differences would not by themselves identify a treatment effect. The record does not describe adjustment methods or a statistical plan.

These limitations do not show that the treatment pathways were ineffective, nor do they demonstrate that outcomes were equivalent. They mean that the posted registry information is insufficient to draw either conclusion. The defensible interpretation is limited to what the record documents: a phase II study with a defined endpoint, a small eligible analysis population in the primary arm, and no reported primary outcome results.

13. Why This Trial Matters Statistically

This record illustrates why a trial’s design and its posted results must be read together. The study has a clearly stated failure definition and follow-up framework, but the primary endpoint counts are not reported. A detailed endpoint definition cannot substitute for the observed result, and a trial label or status cannot reveal what happened to participants.

It also shows why treatment groups in a non-randomized study require careful interpretation. The arms were formed around resectability and margin status, not random assignment. Those features are connected to which treatment pathway patients received and can also be related to outcomes. An arm contrast would therefore mix treatment differences with underlying differences in the patients and disease circumstances.

The distinction between enrollment and the eligible primary analysis population is statistically important. The record reports enrollment of 7 but describes two (2) eligible patients for the endpoint evaluation after one (1) was found ineligible. Without a complete disposition account and endpoint counts, readers cannot determine what information the primary analysis contains or how much uncertainty surrounds an estimate.

Finally, the safety counts demonstrate the limits of interpreting sparse descriptive data. The serious adverse event counts are zero in both listed groups, while the other adverse event counts are small. Such entries should be read as recorded counts, not proof of absence of risk or evidence of a comparative safety effect. Taken together, the record is useful for understanding the study’s structure and definitions, while also showing how missing outcome reporting constrains statistical conclusions.

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 primary endpoint results are not reported in the registry record. Although the endpoint description specifies categories for the data cutoff, no counts are given for failure, failure-free status, withdrawal, or loss to follow-up. No estimate of failure-free survival, confidence interval, or p-value is reported.

The eligible analysis population is described as two (2), after one (1) patient was found ineligible, while overall enrollment is 7. The registry does not provide a complete account of how enrollment relates to each arm, eligibility, follow-up, and endpoint status. This makes the flow of participants difficult to assess.

The trial was non-randomized, and arm membership reflected resectability and surgical margins. The arms are consequently not like-for-like controls. The record does not report adjustment for baseline differences, a statistical analysis plan, or the method used to handle time-to-event information and incomplete follow-up.

The registry states that endpoint data are through March 2008 and describes analyses of 5-year failure-free survival, but participant-level follow-up and endpoint results are not reported. The reason the study was terminated is also not reported in the registry record. The adverse-event entries are sparse; deaths are not reported, and no serious adverse event terms are listed. These limitations restrict both efficacy interpretation and safety assessment.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Surgery and/or Chemotherapy in Treating Children With Infantile, Congenital, or Childhood Fibrosarcoma — NCT00072280.
• Registry record last updated 2014-09-30; status last verified 2014-09.
• Results first posted 2013-11-26.
• 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.

18. Record Summary

This is a non-randomized, unmasked, parallel phase II pilot study sponsored by Children's Oncology Group. Enrollment was 7, and the registry status is terminated. The study evaluated surgery and/or combination chemotherapy for children with fibrosarcoma, using different treatment pathways according to resectability and surgical margins.

The primary endpoint was failure-free survival in the chemotherapy-plus-possible-surgery arm, with failure defined by progression, relapse after response, or death as a first event. The registry says one (1) patient was ineligible, leaving two (2) in the primary analysis population. It does not report the primary endpoint category counts or an inferential analysis.

The listed serious adverse event counts are 0 affected in each arm. Other adverse events were recorded for one participant in the chemotherapy-plus-possible-surgery arm and none in the surgery-only arm. The deaths entries are not reported. Because the study was non-randomized and the endpoint results are absent, the registry record does not support a comparative treatment-effect conclusion.