Chemotherapy Followed by Radiation Therapy in Treating Younger Patients With Newly Diagnosed Localized Central Nervous System Germ Cell Tumors: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Chemotherapy Followed by Radiation Therapy in Treating Younger Patients With Newly Diagnosed Localized Central Nervous System Germ Cell Tumors (NCT01602666), a na phase 2 study. The primary outcome is Neurocognitive Function Using the ALTE07C1 Protocol.

2. Clinical Question

The clinical question is therefore not framed as whether the treatment is better than a control. Rather, the registry describes a study of treatment followed by assessment of cognitive scores in eligible patients who received radiation therapy. The listed secondary outcomes include estimates of progression-free survival and overall survival for patients with non-germinomatous germ cell tumors treated with involved-field radiation therapy, and for localized germinoma groups defined by cerebrospinal fluid and serum hCGbeta levels.

The registry record does not report numerical results for the primary neurocognitive outcome. It also does not report numerical estimates for the listed survival outcomes. Consequently, the record supports a description of what the trial set out to assess, but not a conclusion about the observed cognitive scores or survival distributions.

3. Trial Design

This is a phase 2 clinical trial sponsored by Children's Oncology Group. Its official title describes a phase 2 trial of response-based radiation therapy for patients with localized central nervous system germ cell tumors. The registry lists the study as completed, with enrollment of 262. The recorded start date is 2012-06-27 and the primary completion date is 2024-09-30.

The design is single-group, with allocation recorded as not applicable and masking as none. The treatment group is described as receiving combination chemotherapy and radiation therapy. Listed chemotherapy interventions are carboplatin, etoposide, and ifosfamide; listed radiation interventions are three-dimensional conformal radiation therapy and intensity-modulated radiation therapy. The arm description refers readers to a detailed description, but the registry information available for this analysis does not give a more specific treatment schedule.

The trial covers localized non-germinomatous germ cell tumors and childhood germinoma. The primary outcome is neurocognitive function assessed with the ALTE07C1 protocol, with a timeframe of up to 5 years. The primary outcome description specifies mean standardized scores and 95% confidence intervals. It states that eligible patients who received radiation therapy were evaluable for analysis.

The registry lists seven outcome measures, including secondary outcomes concerning progression-free survival and overall survival in specified patient groups. It records no analysis entries. Numerical primary and secondary outcome results, a detailed statistical analysis plan, and a rationale for the planned enrollment are not reported in the registry record. These omissions prevent assessment of how the final analysis was conducted, which planned comparisons were completed, or how the observed results relate to the intended analyses.

Because there is no randomized comparator, differences between groups cannot be used to estimate a treatment contrast within this study. The single-group design can describe outcomes among the patients included in an analysis, but interpretation depends on the actual results and methods, which 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.

Before assignment: There were 111 patients enrolled in Stratum 1 with localized nongerminomatous germ cell tumors (NGGCT) and 151 patients enrolled in Stratum 2 with localized CNS Germinoma (Germinoma). Of these 107 in Stratum 1 and 137 in Stratum 2 were deemed eligible for the study. This report is limited to eligible subjects.

Induction Chemotherapy

Reasons for not completing this period:

Radiation Therapy on Protocol

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Localized NGGCT treated with 30.6 Gy WVF RT + 23.4 Gy primary site boost. Patients must have had complete response (CR) or partial response (PR) to induction chemotherapy by MRI and markers; or underwent second-look surgery and were found to have mature teratoma, residual scar or fibrosis and fit the definition of CR/PR after second-look surgery.

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 Neurocognitive Function Using the ALTE07C1 Protocol, measured over Up to 5 years.

The primary endpoint is neurocognitive function assessed with the ALTE07C1 protocol. The registry describes three domains: processing speed, attention or concentration, and estimated IQ. Processing speed is measured with the Processing Speed Index from an age-appropriate Wechsler scale. Its stated score range is 45 to 155, with a mean of 100 and a standard deviation of 15. Estimated IQ is derived from two Wechsler subtests and translated to a standard score using published procedures; its stated range is 45 to 158, with a mean of 100 and a standard deviation of 15. Attention or concentration is measured with the Digit Span subtest, whose scores range from 1-19, with a mean of 10 and a standard deviation of 3.

Higher values on all three measures indicate higher or better cognitive performance, while lower values indicate lower or worse cognitive functioning, according to the registry description. Reporting a mean gives a summary of scores in the analysis population; the 95% confidence interval expresses uncertainty around that estimated mean. These are standardized measures, so the stated reference means and standard deviations help describe how scores are scaled. They do not, by themselves, establish how a particular observed score should be interpreted clinically.

Neurocognitive measurement is relevant as a general outcome concept because it captures cognitive functioning rather than tumor control or survival. The registry specifies assessment up to 5 years, but numerical scores, assessment-specific sample sizes, and score estimates are not reported in the registry record. The evaluable population is defined as eligible patients who received radiation therapy; it is not stated to be identical to all enrolled patients.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry specifies the primary outcome as a mean with a 95% confidence interval. A mean is a measure of the center of a set of continuous scores: it combines the values into a single average. A confidence interval conveys the precision of that estimate under the statistical method used. In general, a narrower interval indicates greater precision and a wider interval indicates greater uncertainty. A confidence interval is not a range containing every participant’s score, and it does not show the distribution of individual scores.

What does the endpoint scale describe?

The three neurocognitive measures use different score scales. The Processing Speed Index has a range of 45 to 155, with a reference mean of 100 and standard deviation of 15. Estimated IQ is also expressed as a standard score with a mean of 100 and standard deviation of 15, while its stated range is 45 to 158. The Digit Span subtest has a range of 1-19, a mean of 10, and a standard deviation of 3. These reference values explain the scales described in the registry; they are not trial results. The registry states that higher scores indicate higher or better performance on each measure.

Standardized scoring allows scores to be expressed on defined scales, but does not remove the need to report how many participants were assessed or how scores varied. In general, a mean alone can hide variation: participants with different scores may contribute to the same average. The confidence interval provides information about uncertainty in the estimated mean, but numerical intervals are not reported in the registry record for this endpoint. The record also does not report score distributions or participant counts for individual assessments.

How does the design affect interpretation?

A single-group design describes outcomes observed among participants receiving the study treatment. Without a randomized comparator, it does not estimate a difference between treatment groups. General statistical reasoning distinguishes an outcome estimate from a treatment effect: the former summarizes what was observed in a defined group, while a treatment effect requires a comparison that supports attributing a difference to the treatments being compared. No such within-trial comparison is described.

Allocation is listed as not applicable, and masking is listed as none. The registry does not report other design or analysis details that might clarify how outcome assessment or interpretation was protected from bias. These entries should be read as features of the registry description, not as evidence about the size or direction of any unreported result.

What can a confidence interval establish?

In general, a confidence interval is an uncertainty measure calculated from data and a specified method. It is not a probability statement that the fixed, true value lies inside a particular interval. Its interpretation depends on the assumptions and analysis used. The record specifies a 95% confidence interval for mean scores, but does not state the calculation method, variance assumptions, handling of repeated assessments, or whether estimates were adjusted for other factors. Those analysis details are not reported in the registry record.

The registry’s score definitions describe the instruments, but no actual mean or confidence interval is available to evaluate precision. Consequently, the stated reference means and ranges cannot be used to infer whether participants’ scores were above or below a particular level. Nor can the reported timeframe alone establish how frequently assessments occurred or whether the same participants contributed data at each time point.

What do the secondary outcomes involve?

The listed secondary outcomes concern distributions of progression-free survival and overall survival in specified patient groups. In general, time-to-event outcomes describe the time until a defined event, while accounting for participants whose event status is not observed over the same duration. The registry names the outcome groups and measures, but does not provide event counts, survival estimates, confidence intervals, censoring details, or an analysis method in the information available for this analysis. No conclusions about those distributions can be drawn from their titles alone.

The record lists seven outcome measures and no analysis entries. It does not report a statistical analysis plan, a prespecified hierarchy among outcomes, multiplicity procedures, or the method used for any final estimate. Therefore, it is not possible to determine from the registry record whether the reported analyses, if any, followed a planned approach. The sample-size assumptions described for a planning illustration elsewhere are not the trial’s reported design justification, and no observed effect or sample-size illustration values are available in the registry information.

General statistical practice treats sample-size planning as a design exercise based on assumptions, not as evidence that an analysis was adequately powered after the fact. Any planning illustration should be distinguished from observed evidence. The trial’s own sample-size justification is not reported in the registry record, and no claim about observed power is warranted.

Finally, statistical uncertainty and clinical meaning are related but distinct. A precise estimate can still require clinical context, while a less precise estimate may leave a wide range of plausible values. The registry’s outcome definitions alone do not establish a threshold for meaningful change, and such a threshold is not reported in the registry record. The absence of numerical estimates means neither statistical precision nor clinical importance can be assessed for the primary endpoint.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists seven outcome measures, including the primary neurocognitive endpoint and secondary outcomes concerning progression-free survival and overall survival in specified groups. When multiple outcomes or subgroups are assessed, general statistical reasoning recognizes that the chance of at least one apparently unusual result can increase if each is interpreted separately. Investigators may use a prespecified hierarchy or statistical adjustment to address that issue, but neither an outcome hierarchy nor a multiplicity adjustment is reported in the registry record. It is therefore not possible to determine how the family of outcomes was handled or which measures were intended to support primary conclusions.

The record contains no analysis entries. It does not report a statistical analysis plan, interim analyses, or the methods used to address missing outcome values. Those items are not reported in the registry record; their absence should not be filled in by assumption. The registry’s endpoint timeframe of up to 5 years does not specify the number or timing of assessments, or how incomplete follow-up was managed.

The primary outcome population is described as all eligible patients who received radiation therapy, considered evaluable for analysis. That definition is not the same as the total enrollment of 262, and the number with observed cognitive scores is not reported in the registry record. The record does not describe whether every eligible patient received radiation therapy, how eligibility was operationalized for the outcome analysis, or how patients without an observed score were treated in the analysis. The results therefore cannot be assumed to represent every enrolled participant.

In general, missing data can affect an estimate when the availability of measurements is related to participants’ outcomes or characteristics. The direction and magnitude of any such effect depend on the pattern of missingness and the analysis method. Because neither missingness information nor handling methods are reported, the extent to which incomplete assessments could affect the estimates cannot be judged.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: febrile neutropenia (0.9%), headache (0.9%), hydrocephalus (0.9%), intracranial hemorrhage (0.9%), respiratory failure (0.9%).

The registry reports adverse-event information separately for localized non-germinomatous germ cell tumors and localized germinoma. In the first stratum, 5 of 107 participants at risk are listed as affected by serious adverse events, and 84 of 107 are listed as affected by other adverse events. In the second stratum, 1 of 137 is listed as affected by serious adverse events, and 107 of 137 by other adverse events. The registry also lists 13 deaths in the first stratum and 2 in the second.

These are counts within the listed strata, not a comparison between randomized treatment groups. The registry does not state in this information whether the deaths were caused by treatment, related to the disease, or due to another cause. They should not be interpreted as treatment-attributed deaths. The “other adverse events” counts describe a separate category from serious adverse events; the categories should not be conflated.

The listed serious-event terms are febrile neutropenia, headache, hydrocephalus, intracranial hemorrhage, respiratory failure, and sepsis, each reported as 0.9%. The registry information does not provide event-level detail or establish whether a participant could contribute more than one event term. These figures describe what is recorded, but without a control group they do not estimate excess risk attributable to the treatment.

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

The registry record establishes that a phase 2, single-group trial studied chemotherapy followed by radiation therapy in younger patients with localized central nervous system germ cell tumors. It identifies neurocognitive function as the primary outcome and specifies score instruments, directions of interpretation, and a timeframe of up to 5 years. It also identifies survival outcomes for particular disease groups and provides descriptive adverse-event counts.

However, the record does not report numerical primary or secondary outcome results. It therefore cannot show the observed mean cognitive scores, their confidence intervals, or the reported progression-free and overall survival estimates. Without those results, it is not possible to characterize the magnitude or precision of the observed outcomes. The completion status and enrollment number do not substitute for those estimates.

The design does not include a randomized control group. This means the trial cannot, on its own, establish a comparative treatment effect against another treatment or against no treatment. Even if an outcome estimate were available, a single-group observation would not provide the same causal evidence as a randomized comparison. No claim that the intervention works or does not work follows from the design information alone.

The serious adverse-event counts and listed event terms are also descriptive. They do not identify the cause of individual events or deaths, and they do not provide a comparative estimate of harm. A treatment relationship or comparison with another group is not reported in the registry record.

As a general statistical principle, an outcome definition describes what was intended to be measured, whereas a result reports what was observed and how uncertain that estimate is. Here, the registry supplies the former but does not report the numerical estimates needed for the latter. Any interpretation should therefore be limited to the study’s stated design, outcomes, and descriptive safety information rather than a conclusion about treatment benefit or harm.

13. Why This Trial Matters Statistically

The study raises an important statistical distinction between specifying an outcome and reporting its observed values. The primary endpoint is described in detail: it includes processing speed, attention or concentration, and estimated IQ; identifies standardized scoring approaches; and specifies means with 95% confidence intervals over a timeframe of up to 5 years. Those details make the intended measurement clear, but they do not reveal the results. The lack of numerical estimates means readers cannot assess the observed scores or their precision from the registry record.

The single-group structure is also central to interpretation. It can support a description of outcomes in the treated population, if those outcomes are reported, but it does not create a randomized treatment contrast. This illustrates why a study’s phase and enrollment should not be mistaken for evidence of comparative effectiveness. Interpretation depends on the design and the available results together.

The registry’s distinction between non-germinomatous germ cell tumors and germinoma, as well as its specified survival subgroups, also underscores the importance of reporting analysis populations and subgroup estimates. Without reported analysis entries, participant counts for each outcome, or numerical estimates, it is not possible to determine how those groups contributed to the final analyses.

Finally, the descriptive adverse-event information demonstrates why counts need context. Counts by disease stratum are not a randomized comparison, and deaths cannot be attributed to treatment without supporting information. The trial record thus illustrates a general lesson in biostatistics: outcome definitions, safety counts, and study completion provide useful context, but they do not replace transparent reporting of estimates, uncertainty, analysis populations, and methods.

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 most consequential limitation for interpreting this record is that numerical results for the primary neurocognitive endpoint are not reported in the registry record. There are no mean scores or 95% confidence intervals available to evaluate, despite the stated outcome format. Numerical results for the listed secondary survival outcomes are also not reported. The record therefore permits no assessment of observed outcome magnitude or statistical precision.

The design is single-group, with no randomized control group. This limits causal and comparative interpretation even if outcome estimates are available elsewhere. Masking is listed as none. The registry does not provide further details about outcome assessment procedures or methods that could clarify the potential for measurement or selection bias.

The record reports enrollment of 262, but does not report the number of participants contributing data to each cognitive or survival analysis. The primary outcome population is defined as eligible patients who received radiation therapy, and the number meeting that definition or with observed scores is not reported. Missing data methods, follow-up completeness, assessment timing, and the handling of incomplete outcomes are not reported in the registry record.

Although seven outcome measures are listed, the record contains no analysis entries and does not report a statistical analysis plan, multiplicity approach, or interim analyses. The trial’s sample-size justification is not reported in the registry record. Consequently, the planned outcome structure and the analysis that produced any final estimates cannot be compared.

The adverse-event information provides counts by stratum and selected serious-event terms, but it does not state whether events were considered related to treatment or explain the cause of deaths. Without a control group and fuller attribution information, those counts cannot establish comparative safety or causality.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Chemotherapy Followed by Radiation Therapy in Treating Younger Patients With Newly Diagnosed Localized Central Nervous System Germ Cell Tumors — NCT01602666.
• Registry record last updated 2025-11-20; status last verified 2025-11.
• Results first posted 2020-12-16.
• 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

NCT01602666 is a completed phase 2, single-group trial sponsored by Children's Oncology Group, with enrollment of 262. It studied chemotherapy followed by radiation therapy in younger patients with localized central nervous system germ cell tumors, including non-germinomatous germ cell tumors and childhood germinoma.

The primary outcome is neurocognitive function assessed with the ALTE07C1 protocol. The registry specifies standardized measures of processing speed, attention or concentration, and estimated IQ, reported as means with 95% confidence intervals over a timeframe of up to 5 years. Eligible patients who received radiation therapy are defined as evaluable for this outcome.

The registry lists seven outcome measures and provides descriptive adverse-event information by disease stratum. It contains no analysis entries, and numerical results for the primary and secondary outcomes are not reported in the registry record. The single-group design does not provide a randomized treatment comparison.