Radiosensitization With Celecoxib and Chemoradiation for Head and Neck Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Radiosensitization With Celecoxib and Chemoradiation for Head and Neck Cancer (NCT00581971), a na phase 1, phase 2 study. The primary outcome is Toxicity of Celecoxib With Concurrent Weekly Chemotherapy and Radiotherapy in the Treatment of Locally Advanced or Recurrent Squamous Cell Carcinoma of the Head and Neck..

2. Clinical Question

In statistical terms, the stated question is descriptive: how many participants in this treatment group experienced the specified toxicity during the stated timeframe? It is not a randomized comparison of celecoxib against a control, and the record does not support estimating a treatment effect relative to another regimen.

The outcome description identifies participants as the unit and a count as the measure. That makes the endpoint a binary event at the participant level: each participant either meets the stated toxicity criterion or does not, although the registry does not report the event count for the primary endpoint. It also does not explain how multiple episodes, toxicity grading, or timing within the timeframe were handled.

Thus, the clinical question and the available registry evidence are not equally complete. The question is stated, but the numerical primary outcome needed to describe its observed frequency is not reported in the registry record. The available adverse-event information addresses safety reporting separately and should not be treated as a substitute for that primary outcome.

3. Trial Design

The record describes a single-institution, open-label, non-randomized phase IB/II trial. Its model is single group, and the listed treatment group received celecoxib with carboplatin, paclitaxel, and radiation therapy. Enrollment was 30. The record gives a start date of 2002-09, a primary completion date of 2007-12, and a completed status.

These design features determine what can be learned from the results. A single-group study can describe events observed among participants receiving the regimen. Without a randomized or other concurrent comparison group, however, it cannot isolate the contribution of celecoxib from the other treatments or from factors unrelated to treatment. Non-random allocation also means there is no randomization basis for balancing prognostic factors across treatment groups.

Open-label means masking was absent, according to the record. For an outcome involving toxicity grading, knowledge of treatment can be relevant to assessment and reporting. The registry does not describe whether toxicity assessments used independent review, standardized procedures, or blinded adjudication, so those details cannot be assessed.

The record labels the study phase as phase 1 and phase 2 and describes it in the summary as phase IB/II. It does not report details of dose-escalation procedures, cohort structure, or how the phase components related to one another. Those design elements should not be inferred from the phase label alone.

The record lists two outcome measures and no analysis entries. This does not establish that no analyses were performed; it means that inferential analysis details are not reported in the registry record. Likewise, the stated enrollment does not by itself explain how many participants contributed evaluable information for each outcome or whether any participants were excluded from an analysis.

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

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 Toxicity of Celecoxib With Concurrent Weekly Chemotherapy and Radiotherapy in the Treatment of Locally Advanced or Recurrent Squamous Cell Carcinoma of the Head and Neck., measured over 2 years from radiation therapy.

The primary endpoint is described as the number of participants experiencing acute toxicities above Grade 3. Its timeframe is 2 years from radiation therapy, and the unit is participants. The endpoint therefore concerns the occurrence of a defined level of toxicity among participants, rather than a continuous measurement such as a laboratory value or a time-to-event quantity.

As a general statistical concept, a binary endpoint turns each participant's outcome into an event or non-event according to a prespecified definition. Counting participants with the event can provide a direct description of how often the defined outcome occurred in the study group. The usefulness of that count depends on clear definitions, consistent assessment, and complete outcome ascertainment. The registry's endpoint description does not provide detailed grading rules or explain how multiple episodes were handled.

A toxicity endpoint is relevant to evaluating the tolerability of a regimen because it focuses on adverse events experienced during treatment or follow-up. That general purpose does not establish that the endpoint was measured consistently or that the recorded outcome is complete.

Most importantly, the registry record gives the endpoint definition but does not report the primary endpoint's observed count or an inferential analysis. The adverse-event counts reported separately cannot be assumed to represent the primary endpoint, because the categories and definitions are not shown to be identical. The primary outcome's frequency and precision therefore cannot be described from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count represent?

The primary outcome is expressed as a number of participants meeting a toxicity criterion. As a general statistical explanation, this is a binary outcome when each participant is classified as having or not having the specified event. A count is a direct summary of observed events, but it is most informative when paired with a clearly defined denominator and a precise outcome definition. Here the record specifies the unit and timeframe, but does not report the primary event count, the number analyzed for that outcome, or detailed operational rules for assigning the toxicity classification.

For the adverse-event summaries, the record reports affected participants and participants at risk. These quantities describe the recorded safety experience in the treatment group. They do not provide a treatment contrast: a comparison requires information from a suitable comparator group and an analysis that defines the contrast. This trial is listed as single group, with no randomized control arm.

What would an interval estimate add?

As a general concept, a confidence interval expresses the uncertainty around an estimated quantity under the assumptions of the statistical method. For a binary event proportion, an interval can show how much the estimated frequency might vary because only a limited group was observed. An interval does not remove systematic limitations such as incomplete ascertainment, subjective grading, or lack of a comparator. No confidence interval for the primary toxicity endpoint is reported in the registry record, and the primary event count needed to describe such an estimate is also absent.

Why does the design matter for inference?

In a randomized comparison, random assignment can support a causal comparison between treatment groups, subject to adherence, follow-up, measurement, and analysis assumptions. In a single-group study, observed events can be described, but there is no concurrent randomized group to establish a counterfactual outcome. In general, changes over time, patient characteristics, other components of a combination regimen, and differences in observation can all complicate attribution. In this trial, celecoxib was given with carboplatin, paclitaxel, and radiation therapy, so the record cannot separate the effect of one component from the combined regimen.

What do the planning assumptions mean?

The record's planning assumptions describe an illustration based on an observed effect, not the trial's own design. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect defined as a stated fraction of the observed effect. For time-to-event calculations, the stated convention is a total event count using the Schoenfeld method; other calculations are expressed as participants per arm.

These assumptions need to be distinguished from the actual study. The trial is recorded as single group and non-randomized, whereas equal allocation between two arms describes a hypothetical two-arm planning setup. Such a calculation does not reconstruct the study's design or demonstrate that the trial had a particular probability of detecting an effect. Sample-size calculations are planning illustrations, not observed power. The registry record does not report a sample-size justification for the trial.

Why might over-dispersion matter in general?

For count outcomes, a simple model may assume that the variability is described by the mean count. Over-dispersion occurs when actual variation is greater than that assumption allows. If it is ignored, standard errors can be too small and intervals or tests can appear more precise than warranted. This general issue is relevant to repeated event counts or clustered observations, but the primary endpoint is described as a participant count, and the registry does not report a model for it. There is no basis in the record to say that an over-dispersion adjustment was used or needed.

What analysis details are missing?

The registry lists no analysis entries. It does not report a statistical model, a hypothesis test, covariate adjustment, handling of incomplete outcomes, or a prespecified analysis population. These absences prevent assessment of whether the primary endpoint was analyzed as a proportion, whether any adjusted estimate was intended, and how uncertainty was quantified. They should be described as details not reported in the registry record, rather than as proof that no statistical work took place.

10. Multiplicity, Missing Data and Analysis Populations

The record lists two outcome measures and no analysis entries. It does not report a multiplicity strategy, such as how interpretation would account for testing more than one outcome or conducting more than one analysis. Without that information, the registry record does not establish whether the primary outcome was the only confirmatory test, whether other outcomes were exploratory, or whether any adjustment to statistical thresholds was planned.

Multiplicity is a general statistical concern when several hypotheses are evaluated. The more opportunities there are to identify an apparently unusual result, the more important it is to distinguish prespecified primary analyses from additional exploratory analyses. That concern cannot be quantified for this trial from the registry record, because the analysis plan and analysis results are not reported.

Missing-data procedures are also not reported in the registry record. The available description does not state how participants with incomplete toxicity follow-up, unavailable assessments, or other missing outcome information were handled. Nor does it state whether analyses used all enrolled participants, only participants with observed outcomes, or another defined analysis population. Enrollment of 30 is not a substitute for an outcome-specific denominator.

These omissions matter because the interpretation of a count depends on who was assessed and how incomplete follow-up was treated. If outcome availability differed across participants, a count among those assessed could describe a different population from the full enrolled group. This is a general methodological point, not a claim about what occurred in this trial.

The appropriate conclusion is limited: multiplicity procedures, missing-data methods, and analysis-population definitions are not reported in the registry record. The absence of these details prevents a full appraisal of the intended inferential framework.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: vomiting (10.0%), neutropenia (10.0%), febrile neutropenia (6.7%), stroke (3.3%), anemia (3.3%).

The registry reports serious adverse events for the treatment group as 12 affected among 30 at risk. For other adverse events, it reports 29 affected among 30 at risk. These figures refer to participants, not necessarily to the number of individual event episodes. The record does not explain whether one participant could be counted under multiple event terms or how events were attributed to treatment.

The listed serious adverse-event terms and percentages are vomiting, 10.0%; neutropenia, 10.0%; febrile neutropenia, 6.7%; stroke, 3.3%; anemia, 3.3%; and pneumonia, 3.3%. These term-level percentages should be read as reported. The registry does not specify whether the terms overlap at the participant level, so they should not be added together or interpreted as separate, mutually exclusive groups.

As a general point, an adverse-event listing describes events recorded under a study's collection and classification procedures. It does not, by itself, establish that the treatment caused an event. In this single-group study there is no concurrent randomized comparison for estimating whether event frequency differed under another regimen. The record also does not provide further detail on event timing or outcomes for these terms.

The primary endpoint is separately described as acute toxicities above Grade 3, but its numerical result is not reported in the registry record. The safety summaries therefore should not be substituted for the missing primary endpoint result.

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

The record establishes that the trial evaluated a combined regimen of celecoxib, carboplatin, paclitaxel, and radiation therapy in a single group of patients with locally advanced or recurrent squamous cell carcinoma of the head and neck. It also identifies a primary toxicity question, gives its timeframe, and reports selected adverse-event counts and term-level percentages.

It does not report the numerical result for the primary endpoint. Therefore, the observed frequency of acute toxicities above Grade 3 cannot be stated from the registry record, and the precision of that primary outcome cannot be assessed. No inferential analysis for the primary endpoint is reported in the registry record.

The reported serious and other adverse-event counts describe the listed group, but do not establish a causal relationship or comparative safety. Since no concurrent control group is listed, these counts cannot show how the event experience would compare with another treatment. The combined regimen also prevents isolating the contribution of celecoxib from the other components.

As a general statistical distinction, describing observed events is not the same as estimating a treatment effect. A treatment effect requires a defined contrast, suitable data, and an analysis that addresses uncertainty and relevant design assumptions. A single-group count can inform a descriptive account of what was recorded, but it cannot supply the missing counterfactual comparison.

The completed status and enrollment figure provide trial context, not evidence that every endpoint result or analysis is present in the registry. The record does not report outcome-specific denominators, missing-data procedures, analysis populations, or multiplicity methods. Those limitations constrain the extent to which the available information can be interpreted.

Accordingly, the record supports a description of the trial design and the safety counts that it reports. It does not support a conclusion about the primary toxicity result, a comparative treatment effect, or the causal contribution of any single regimen component.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of the distinction between a clearly stated clinical question and a fully reported result. The record identifies a participant-level toxicity endpoint and its timeframe, but does not report the endpoint's observed numerical result. A registered outcome definition alone is not enough to evaluate the observed frequency or its precision.

The single-group, non-randomized design also makes the scope of inference important. Such a design can describe events among participants receiving the regimen, but it does not create a concurrent randomized counterfactual. This is particularly relevant for a multi-component regimen, where an observed outcome cannot be attributed to celecoxib alone on the basis of this design.

The registry's safety counts illustrate why denominators and event definitions matter. Counts of affected participants and listed event terms are useful descriptive information, but terms may overlap, and a participant count is not necessarily an episode count. The record does not resolve that overlap or report additional event-level detail.

Finally, the stated planning assumptions are not the same as the study's actual design or an observed power calculation. The assumptions describe a two-arm planning illustration, while the trial is registered as single group. Keeping those concepts separate prevents planning calculations from being misread as evidence of the study's precision or as a reconstruction of its original rationale.

The main statistical lesson is to match each claim to the design and reporting available: describe what the registry reports, identify what it omits, and avoid turning a one-group safety summary into a comparative or causal conclusion.

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 direct limitation is that the registry record does not report the numerical primary endpoint result, despite defining the outcome and timeframe. This prevents assessment of the primary outcome's observed frequency and statistical precision.

The trial is open-label, non-randomized, and single group. There is no concurrent randomized comparator in the record, so observed outcomes cannot be used to estimate a randomized treatment contrast. The intervention combines celecoxib with carboplatin, paclitaxel, and radiation therapy; the design does not separate the contribution of individual components.

The trial is described as single-institution, which limits how confidently its descriptive findings can be generalized to settings or patient groups not represented in the record. The summary identifies locally advanced or recurrent squamous cell carcinoma of the head and neck, but the registry does not report further population characteristics in the primary outcome description.

Although the primary endpoint concerns acute toxicities above Grade 3 within 2 years from radiation therapy, the record does not report detailed grading procedures, assessment schedules, or how repeat events were handled. It also does not report the primary endpoint denominator or how missing assessments were treated. The reported adverse-event counts do not resolve these gaps because they are presented as separate safety information.

Analysis entries are absent, and the record does not report the analysis population, statistical model, multiplicity approach, or missing-data methods. These omissions limit assessment of the inferential plan. They should not be interpreted as proof that no analyses or procedures existed outside the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Radiosensitization With Celecoxib and Chemoradiation for Head and Neck Cancer — NCT00581971.
• Registry record last updated 2013-04-25; status last verified 2013-03.
• Results first posted 2013-04-25.
• 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

NCT00581971 is listed as a completed, single-institution, open-label, non-randomized phase IB/II trial with a single group and enrollment of 30. The regimen combined celecoxib, carboplatin, paclitaxel, and radiation therapy for patients with locally advanced or recurrent squamous cell carcinoma of the head and neck.

The primary outcome concerns participants experiencing acute toxicities above Grade 3 within 2 years from radiation therapy. Its numerical result and inferential analysis are not reported in the registry record. The safety information reports serious adverse events in 12 participants among 30 at risk and other adverse events in 29 participants among 30 at risk, with selected term-level percentages.

The record lists two outcome measures and no analysis entries. It does not report a comparator group, outcome-specific analysis population, missing-data procedure, multiplicity method, or sample-size justification. The available evidence supports a descriptive account of the trial and listed safety information, not a comparative treatment-effect estimate.