Nab-Paclitaxel, Cetuximab, Cisplatin, and Radiation Therapy in Treating Patients With Recurrent Head and Neck Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Nab-Paclitaxel, Cetuximab, Cisplatin, and Radiation Therapy in Treating Patients With Recurrent Head and Neck Cancer (NCT00833261), a na phase 2 study. The primary outcome is Progression Free Survival (PFS).

2. Clinical Question

The clinical question is therefore descriptive: what progression-free survival was observed in participants receiving this combination within a single-arm phase II study? Without a concurrent comparison group, the study cannot estimate a randomized difference between this regimen and another option. The record identifies acute and late toxicities as a secondary outcome, but does not provide their timing rules or a complete set of outcome results. Although the enrollment total is 37, the safety group lists 33 participants at risk for the reported serious and other adverse events. The registry record does not explain the relationship between those counts or identify the number included in the primary endpoint analysis.

3. Trial Design

This was a phase II, multicenter study with a single treatment group. The title identifies recurrent head and neck cancer, while the official title specifies recurrent squamous cell carcinoma of the head-and-neck. The registry lists Head and Neck Cancer as the condition. The sponsor was University of Texas Southwestern Medical Center. Enrollment was 37. The recorded start was 2008-12, primary completion was 2013-09, and status is COMPLETED.

Participants received Nab-Paclitaxel, cetuximab, and cisplatin alongside intensity-modulated radiation therapy. The treatment arm is described as chemotherapy with concurrent radiation therapy. Allocation is listed as NA, the model as single group, and masking as none. Thus the design has no concurrent control arm and no masking. These features are essential to interpretation: the posted results describe outcomes within a treated group, rather than a comparison generated by random assignment.

The primary endpoint is percentage of participants with progression-free survival at 2 year from enrollment. The endpoint description defines progression-free survival as time from enrollment until the first new metastatic lesion, objective tumor progression, or death. The secondary outcome listed is the number of participants with acute and late toxicities. Although the record states that there are 2 outcome measures, the numerical progression-free survival result and details for the other outcome measure are not reported in the registry record.

Further design details that would help assess the trial are not reported in the registry record. These include eligibility criteria, treatment schedules and dose modifications, follow-up assessment procedures, criteria for progression, the analysis population, and the statistical analysis plan. The enrollment total alone does not establish how many participants had outcome data or how many contributed to each analysis. Nor does the completed status indicate whether all planned outcomes were 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

Reasons for not completing this period:

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.

Population: Three patients withdrew from the study prior to treatment.

6. Primary Endpoint

The registry lists the primary outcome as Progression Free Survival (PFS), measured over 2 year from the date of enrollment.

The primary endpoint is the percentage of participants with progression-free survival at 2 year from the date of enrollment. The registry defines progression-free survival as the time from enrollment to the first occurrence of new metastatic lesions, objective tumor progression, or death. This is a time-to-event outcome: each participant is followed until an event occurs or until follow-up ends without a recorded event. The endpoint combines several kinds of clinical event into one measure, so an event can be counted even if the other event types have not occurred.

In general, progression-free survival is used to describe how long participants remain alive without documented progression under a study’s assessment rules. It can capture both tumor progression and death, whereas an endpoint limited to death would not count progression in a participant who remains alive. The percentage at a specified time point is a summary of the proportion estimated to remain event-free through that point, rather than a count of how many participants were event-free at every moment during follow-up. Estimation often accounts for participants whose follow-up ends before the time point, but the method used in this trial is not reported in the registry record.

The registry describes follow-up through death or, for participants alive at last evaluation, from 7.5 months to 63.6 months, with median 25.6 months. It does not report the primary endpoint estimate, its confidence interval, the number of progression or death events, or the number at risk at the 2-year time point. Without those results, the endpoint definition can be explained, but the observed progression-free survival cannot be quantified.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record supplies an endpoint definition and selected safety counts, but does not report the primary endpoint estimate or the statistical analysis plan. Statistical concepts can still clarify what the reported measures would mean and which information is needed to interpret them. The explanations below are general unless they explicitly describe a trial feature recorded in the registry.

What does a time-to-event endpoint represent?

In general, a time-to-event endpoint measures elapsed time from a defined starting point until a specified event. Here, the recorded starting point is enrollment, and the event is the first of new metastatic lesions, objective tumor progression, or death. Combining event types means that the endpoint captures the first qualifying event, regardless of which component occurs first. The registry labels the primary outcome as a percentage of participants and specifies a 2-year time point, rather than reporting a median time or a hazard ratio.

A time-to-event analysis can use information from participants who have not had an event by their last known assessment. Such participants are commonly described as censored at that time: their follow-up contributes information up to the last point at which their status is known, but their later event status is unknown. In general, this approach depends on adequate follow-up and assumptions about censoring. The registry record does not report the estimator used, the censoring rules, the number censored, or whether any participants were lost to follow-up.

How should a confidence interval be read?

In general, a confidence interval expresses uncertainty around an estimated quantity. A 95% confidence interval gives a range of values compatible with the observed data under the method’s assumptions; it is not a guarantee that the true value lies within that particular interval. A narrower interval indicates greater statistical precision than a wider interval, all else equal. The endpoint description identifies a 95% confidence interval as the dispersion measure, but neither the interval nor the point estimate is reported in the registry record. Precision therefore cannot be judged from the endpoint definition alone.

For a percentage estimated from time-to-event data, the interval depends on the estimation procedure and the amount and timing of observed follow-up and events. The total enrollment is not enough to reconstruct the interval: participants can have different follow-up durations, and the endpoint may be affected by censoring. No recalculated estimate is available in the registry record, and no further calculation can be inferred from the listed enrollment total.

Why does the single-group design matter?

In general, a single-arm study can describe outcomes among participants who received the study regimen. It cannot separate the treatment’s association with an outcome from other explanations as effectively as a randomized controlled comparison. Differences in patient characteristics, disease severity, follow-up, and outcome assessment can affect comparisons with results from other groups or studies. This record lists allocation as NA and the model as single group, so the interpretation should remain within-group and descriptive.

Masking is listed as none. In general, lack of masking can matter when outcome assessment or reporting involves judgment, because knowledge of treatment may influence how an outcome is assessed. The registry definition includes objective tumor progression, but the criteria and assessment procedures are not reported in the registry record. It is not possible to determine from the listed design fields how this feature affected ascertainment.

What can event counts and percentages tell the reader?

In general, an adverse-event count is meaningful only alongside its denominator and the rules used to define and collect events. The safety information lists 33 participants at risk for serious events and 21 affected; it also lists 33 at risk for other events and 10 affected. The record does not define the distinction between these categories, state whether participants could contribute to both, or provide the event collection period. The listed serious-event term percentages describe the registry’s reported frequencies, but the record does not provide additional information on grading, duration, recurrence, or attribution to treatment.

Event percentages are descriptive and do not establish whether events were caused by treatment. A comparison group can help provide context for relative event frequency, but none is included in this trial. Further, counts of participants affected are not necessarily counts of separate event episodes; a participant might experience more than one event. The registry record does not clarify whether the figures refer to participants or episodes beyond the group fields’ affected-participant labeling.

What does a planning illustration mean?

In general, a sample-size planning illustration asks how many participants might be needed to detect a specified effect under stated assumptions. Such a calculation is not an observed result, does not indicate the probability that the trial’s finding is true, and is not observed power. The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of an observed effect. For time-to-event outcomes, the assumption text refers to a total event count; for other outcomes, it refers to participants per arm.

Those assumptions describe a hypothetical planning exercise, not the actual design of this single-group trial, which has no two-arm allocation. The registry record does not report the trial’s own sample-size justification. The observed primary endpoint result is also not reported, so no particular effect or planning count can be interpreted from the registry information. Any planning figures should be treated as illustrations under their assumptions, rather than evidence about the study’s observed performance.

What remains unknown about the analysis?

The registry record lists 2 outcome measures and no analysis records. It does not describe the estimator for progression-free survival, the confidence interval method, prespecified analysis populations, missing-data handling, or any adjustment for multiple outcomes. General statistical principles can explain why those details matter, but they cannot identify which methods were used in this study. Without that information and the numerical endpoint result, readers cannot independently assess the precision or robustness of the primary finding.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Single Arm: Chemotherapy With Concurrent Radiation")
n      <- c(33)
events <- c(20)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Single Arm: Chemotherapy With Concurrent Radiation  33  20  60.6  42.1  77.1  43.7  75.3  43.6  75.4

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures and identifies progression-free survival as the primary outcome, with acute and late toxicities as a secondary outcome. Evaluating more than one outcome raises a general multiplicity question: when several statistical claims are considered together, the chance of at least one apparently positive finding can increase if each is tested without adjustment. Whether adjustment is needed depends on the objectives, outcome hierarchy, and planned analyses. A multiplicity strategy, testing hierarchy, or rationale for not adjusting is not reported in the registry record.

The record identifies a 95% confidence interval for the primary endpoint, but does not report the interval or a statistical analysis plan. It also lists no analysis records. The primary outcome definition and the existence of a secondary toxicity outcome do not reveal whether formal hypothesis tests were conducted, whether interim analyses occurred, or how any such analyses were handled. Interim analyses and their methods are not reported in the registry record.

Missing-data handling is also not reported. For a time-to-event outcome, follow-up can end before an event is observed; the registry gives follow-up information for participants alive at last evaluation but does not provide censoring counts or rules. It does not describe missing assessments, loss to follow-up, or any sensitivity analyses. The analysis populations are not reported either. The enrollment of 37 and safety group denominator of 33 do not establish which participants contributed to each outcome or why the denominators differ.

In general, clear reporting of these choices helps readers judge whether outcome estimates are vulnerable to selective analysis or incomplete observation. Here, the registry information is insufficient to assess those issues. It does not establish that analyses were absent; it establishes that analysis records and corresponding methodological details are not reported in the registry record.

12. 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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: lymphopenia (63.6%), infection (21.2%), dermatitis (18.2%), neutropenia (12.1%), leukopenia (9.1%).

The registry lists a single safety group with 33 participants at risk for serious adverse events and 21 affected. For other adverse events, it lists 33 at risk and 10 affected. It reports 0 deaths in the group. The top listed serious-event terms and percentages are lymphopenia, 63.6%; infection, 21.2%; dermatitis, 18.2%; neutropenia, 12.1%; leukopenia, 9.1%; and anemia, 9.1%.

These figures should be read as the recorded safety information for the listed group, not as a comparison between treatments. The percentages for event terms are registry-reported values; the record does not provide detail about event grades, duration, recurrence, attribution, or the specific observation period. It also does not explain how participants were selected into the group of 33 from the total enrollment of 37. The number of participants with an event is distinct from the number of event episodes, and the registry does not clarify whether the term percentages count participants or repeated occurrences.

The 0 deaths reported in the safety group do not establish the 2-year progression-free survival result. Progression-free survival also includes progression events, and the registry does not report the primary endpoint estimate or how its analysis population relates to the safety group.

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

The registry record describes a phase II study of a four-component treatment regimen for recurrent head and neck cancer, delivered in a single group. It identifies a 2-year progression-free survival endpoint and defines the events that count toward it. Those details explain the clinical outcome the study set out to measure. However, the numerical result for progression-free survival is not reported in the registry record. The record therefore does not establish the percentage of participants who were progression-free at the specified time point or the precision of that estimate.

The enrollment total of 37 gives the size of the study as recorded, but it does not show how many participants were included in each outcome analysis. The safety group has 33 participants at risk, and its adverse-event counts and listed percentages describe the reported safety findings for that group. They do not provide a comparative estimate of risk, and there is no control arm from which to estimate a treatment contrast.

In general, an outcome observed in a single treatment group is not sufficient to show what would have happened to the same participants under an alternative. The study can describe outcomes among enrolled participants, but differences from another population or historical experience may reflect differences in participant characteristics, follow-up, assessment, or other factors. The absence of a comparator is a design limitation, not proof that the treatment had a particular effect.

The registry record also does not report the analysis methods, missing-data procedures, analysis populations, or multiplicity strategy. As a result, readers cannot assess how the endpoint was estimated, how incomplete follow-up was handled, or whether the reported outcome is robust to alternative analytic choices. The study status is COMPLETED, but completion alone does not supply these missing details. The most defensible reading is that the registry identifies the study question and some safety information while leaving the primary efficacy result and key analytical context unreported.

14. Why This Trial Matters Statistically

This trial illustrates a central distinction in clinical-trial interpretation: an endpoint definition is not an endpoint result. The registry specifies progression-free survival at 2 year from enrollment and defines the events that count, but it does not report the estimated percentage or its confidence interval. A reader can identify what the investigators intended to measure, yet cannot evaluate the observed magnitude or its precision from the registry record.

It also demonstrates why design structure determines the kinds of conclusions a study can support. This is a single-group phase II trial with no comparator arm. Its outcomes can characterize participants treated in the study, but they cannot provide a randomized contrast. This distinction matters when readers encounter claims or comparisons that imply the regimen’s outcomes are better or worse than another treatment; such claims require evidence beyond a within-group result.

The safety information offers a further lesson about denominators. Enrollment is 37, while the reported safety group has 33 participants at risk. The registry does not explain the difference, and readers should not silently treat either number as the denominator for every outcome. Event counts, percentages, analysis populations, and follow-up periods need to be understood together for meaningful interpretation.

Finally, the record shows the value of reporting analytical methods alongside outcomes. A time-to-event estimate depends on follow-up and censoring, and interpretation of multiple outcomes depends on the analysis plan. Because the estimate, analysis methods, and missing-data procedures are not reported, the key statistical uncertainties remain unresolved. These gaps limit what can be concluded from the registry entry, regardless of the study’s completed status.

15. 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 important trial-specific limitation in the registry record is that the primary progression-free survival result is not reported. The endpoint is defined, but no percentage, confidence interval, event count, or number at risk at the 2-year time point is available. This prevents assessment of the size and precision of the primary outcome.

The study is single group, allocation is listed as NA, and masking is listed as none. Without a concurrent comparator, the design cannot estimate a randomized treatment difference. The record also does not report the eligibility criteria, baseline participant characteristics, treatment doses or schedules, treatment exposure, or reasons participants may have stopped treatment or follow-up. These omissions constrain assessment of who the results represent and how treatment was delivered.

The total enrollment was 37, whereas the safety information lists 33 participants at risk. The registry does not explain this denominator difference or specify the analysis population for progression-free survival. It reports follow-up among participants alive at last evaluation, but does not state the number with complete follow-up, the censoring rules, or how missing assessments were handled. This makes it difficult to assess the completeness of outcome observation.

Statistical methods are also incompletely described. No analysis records are listed, and the registry does not report the estimation method, the statistical analysis plan, multiplicity procedures, or sensitivity analyses. The safety information does not provide event grades, timing, duration, or attribution, and no comparison group is available to contextualize the listed adverse events. These limitations arise from information not reported in the registry record; they do not establish that the underlying study did not collect or analyze the information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Nab-Paclitaxel, Cetuximab, Cisplatin, and Radiation Therapy in Treating Patients With Recurrent Head and Neck Cancer — NCT00833261.
• Registry record last updated 2020-08-21; status last verified 2018-11.
• Results first posted 2019-07-05.
• 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.

19. Record Summary

The registry record describes a completed, multicenter, single-group phase II study sponsored by University of Texas Southwestern Medical Center. Enrollment was 37, and the intervention combined Nab-Paclitaxel, cetuximab, cisplatin, and intensity-modulated radiation therapy for recurrent head and neck cancer. The primary endpoint was the percentage with progression-free survival at 2 year from enrollment, defined by new metastatic lesions, objective tumor progression, or death.

The numerical primary endpoint result and its confidence interval are not reported in the registry record. The safety group lists 33 participants at risk, with 21 affected by serious adverse events and 10 affected by other adverse events; 0 deaths are reported in that group. Key information about analysis methods, endpoint populations, and missing data is also not reported. Because there is no comparator arm, the study describes outcomes within one treated group rather than a randomized treatment comparison.