Efficacy of Neoadjuvant Chemoradiation for Potentially Resectable Pancreas Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy of Neoadjuvant Chemoradiation for Potentially Resectable Pancreas Cancer (NCT00557492), a na phase 2 study. The primary outcome is Rate of Margin Negative Surgical Resection (R0 Resection Rate).

2. Clinical Question

3. Trial Design

This was a completed phase II, single-group study of preoperative treatment for potentially resectable pancreatic cancer. The registry lists enrollment of 59 and identifies the condition as pancreatic cancer. It describes a regimen involving bevacizumab, gemcitabine and external beam radiotherapy. The study began in 2006-12, and primary completion is listed as 2012-03. These dates describe the record; they do not establish when each participant received treatment or when an outcome was assessed.

The listed bevacizumab schedule was 10 mg/kg on days 1, 15, 29 and 43. Gemcitabine was listed at 1500 mg/m2 intravenously over 150 minutes on days 1, 15 and 29, administered at a fixed-dose rate of 10 mg/m2/min. The radiotherapy description reads 3 Gy/ and does not give a complete schedule. The full treatment protocol, including any additional administration details, is not reported in the registry record.

There was no randomized allocation and no masking. Because the design is single-group, outcomes can describe what occurred among participants in this study, but they cannot by themselves separate treatment effects from other explanations such as patient selection, the natural course of disease or other care. A comparison with another group would be needed to estimate a relative effect under comparable conditions.

The primary endpoint was the rate of margin-negative surgical resection, with a timeframe listed as up to 48 months. The registry also names overall survival, progression-free survival, rate of surgical resection, radiographic tumor response and serum CA 19-9 biomarker response as secondary outcomes. Although nine outcome measures are recorded overall, numerical outcome results and analysis details are not reported in the registry record. The record lists the study status as completed, which does not substitute for numerical findings.

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:

Analysis population for the primary outcome, as defined in the registry: Participants who underwent laparoscopy and pancreatic resection.

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 Rate of Margin Negative Surgical Resection (R0 Resection Rate), measured over Up to 48 months.

The primary endpoint is the rate of margin-negative surgical resection, also termed the R0 resection rate. It concerns whether a pancreatic resection had margins classified as negative. The registry describes the numerator as participants who underwent laparoscopy and pancreatic resection with negative margins, and the denominator as participants who underwent laparoscopy and pancreatic resection. The listed timeframe is up to 48 months.

This endpoint is relevant to a preoperative study because it records a surgical result following treatment, rather than only a change in imaging or a laboratory marker. It is a binary outcome at the participant level: the endpoint concerns whether the specified surgical result occurred. A rate can make the frequency of that outcome interpretable within the population used for its denominator. It does not, on its own, establish why the outcome occurred or how it compares with what would have happened under another treatment.

The record specifies a 95% confidence interval as the dispersion measure, but it does not report the observed rate or the interval limits. The denominator wording also focuses on participants who underwent both laparoscopy and pancreatic resection. It therefore does not describe a rate among all enrolled participants. How participants who did not proceed to resection were handled in other analyses is not reported in the registry record. That distinction matters when interpreting the endpoint: it is an estimate for the defined surgical population, not necessarily an estimate of the probability of margin-negative resection for everyone enrolled.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

A clinical endpoint turns a research question into an outcome that can be recorded for each participant. Here, the primary endpoint is a margin-negative surgical resection, and the registry reports it as a rate. In general, a rate for a binary outcome is an estimate of the proportion of the relevant analysis population with the outcome. The registry’s definition makes the relevant population participants who underwent laparoscopy and pancreatic resection. That detail is essential: the result would answer a question about that defined group, not automatically about everyone enrolled.

The registry specifies a 95% confidence interval for the primary endpoint. In general, a confidence interval communicates the statistical uncertainty around an estimated quantity. A narrower interval indicates greater precision under the method used; a wider interval indicates less precision. The interval does not show the range of individual participant outcomes, and it is not a guarantee that a particular value is correct. The numerical estimate and interval bounds are not reported in the registry record, and the method used to calculate the interval is not reported there either.

The endpoint is a binary outcome, so methods for estimating a proportion are conceptually relevant. Different approaches to proportion intervals can behave differently, particularly when the analysis population is small or the outcome is uncommon. The registry record does not name the interval procedure or provide the underlying endpoint counts. It would therefore be inappropriate to reconstruct an endpoint estimate or choose a method on the record’s behalf.

The design is single-group. In general, an estimate from a single group is descriptive of the participants observed, while a controlled comparison is needed to estimate how outcomes differ between treatment strategies under the study design. Random allocation can help balance measured and unmeasured characteristics between groups, on average. Since this study has no concurrent control group, those comparative features are absent. The posted design cannot isolate the effect of the regimen from other causes of the observed outcomes.

Masking is listed as none. In general, masking can reduce the risk that knowledge of treatment influences care, outcome assessment or reporting, depending on the outcome and the role of the people involved. A surgical margin outcome may involve assessment processes, but the details of outcome adjudication and safeguards against assessment bias are not reported in the registry record. The lack of masking is a design feature, not proof that a particular assessment was biased.

Some endpoints are measured over time. Overall survival and progression-free survival are listed as secondary outcomes. General methods for time-to-event outcomes account for the fact that some participants may not have had the event by the end of their observed follow-up. Such methods rely on information about event times and censoring, including when follow-up ends without an event. The registry record does not report time-to-event estimates, event counts, follow-up summaries or the analysis method. No specific survival result can therefore be interpreted from the record.

The sample-size planning assumptions described for the statistical illustrations are not the trial’s own design rationale. They use a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. For time-to-event illustrations, the stated quantity is total events; for other illustrations, it is participants per arm. These are planning conventions, not observed power, and they do not turn this single-group study into a two-arm trial. The registry does not report the study’s own sample-size justification or the assumptions used in its design.

In general, planning calculations depend on the target effect, outcome variability, statistical test, error rate and design. A planning illustration can show how changing assumptions changes a hypothetical requirement, but it does not tell whether a completed study detected an effect or whether its result is precise. No numerical planning results are stated in the registry record. The actual trial enrollment is recorded as 59, but that number alone does not indicate the study’s power or the precision of its primary endpoint.

Adverse-event summaries also require care. A participant count affected is not necessarily the same as a count of separate event occurrences, because one participant can experience more than one event. A percentage attached to a listed event term is descriptive; interpretation depends on its denominator, collection rules, follow-up, severity definitions and attribution procedures. Those details are not all reported in the registry record. Seriousness and severity are also distinct concepts in general: seriousness is a regulatory classification based on consequences, while severity describes intensity. The registry’s serious-event listing should not be read as a complete grading distribution.

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("FDR GEM + BEV +/- BEV/RT")
n      <- c(43)
events <- c(38)
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  FDR GEM + BEV +/- BEV/RT  43  38  88.4  74.9  96.1  75.5  94.9  75.4  94.8

11. Multiplicity, Missing Data and Analysis Populations

The registry lists several secondary outcomes in addition to the primary surgical endpoint. When a study assesses multiple outcomes, general statistical practice considers whether and how to control the chance of false-positive findings across those tests. Such procedures may adjust significance thresholds or organize outcomes into a prespecified hierarchy. Whether any such approach was planned or used is not reported in the registry record. No analysis entries are listed, so there are no posted inferential results from which to assess multiplicity handling.

Missing-data handling is also not described. The record does not explain how unavailable endpoint information, incomplete follow-up or withdrawal was handled. This is especially relevant to the primary endpoint because its stated denominator consists of participants who underwent laparoscopy and pancreatic resection, rather than all enrolled participants. The record does not state how participants who did not reach that stage were handled in other outcome summaries, or whether any missingness assumptions were used.

The registry defines the primary endpoint population in terms of surgery, but does not provide a broader analysis-population plan. It does not report whether analyses were intended to include all enrolled participants, those who began treatment, or another defined group. Details of eligibility, exclusions from analyses and protocol deviations are not reported in the registry record. As a result, the relationship between enrollment, treatment exposure, surgery and the endpoint denominator cannot be fully evaluated.

These omissions do not establish that a particular procedure was or was not followed; they mean the registry record does not document it. Without a statistical analysis plan or posted analysis results, readers cannot verify prespecification, multiplicity control, missing-data assumptions or the population used for each endpoint.

12. 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: thrombosis/thrombus/embolism (5.1%), infection with normal anc or grade 1 or 2 neutrophils, abdomen nos (3.4%), wound complication, non-infectious (1.7%), dehydration (1.7%), leak (including anastomotic), gi, pancreas (1.7%).

The registry safety entry lists 59 participants at risk for serious adverse events and 10 affected. For other adverse events, it lists 59 at risk and 50 affected. These are participant counts in the posted record; they should not be treated as counts of event episodes, since an affected participant may have experienced more than one event. The record does not state how events were attributed to treatment components.

The serious-event terms include thrombosis/thrombus/embolism at 5.1%, infection with normal ANC or Grade 1 or 2 neutrophils, Abdomen NOS at 3.4%, and wound complication, non-infectious at 1.7%. Dehydration, leak (including anastomotic), GI, Pancreas, and nausea are each listed at 1.7%. The registry does not explain the denominator for each term in the listing, so these percentages should be read as recorded rather than recalculated or assumed to use a particular denominator.

Death information is not reported in the registry record. The safety summary does not provide event timing, duration, outcome, severity grading or treatment attribution details. These figures describe recorded adverse-event information and do not, by themselves, establish causation or permit comparison with another regimen.

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

The registry record establishes that a completed phase II, single-group study evaluated preoperative bevacizumab, gemcitabine and external beam radiotherapy in potentially resectable pancreatic cancer. It identifies margin-negative surgical resection as the primary endpoint and specifies a 95% confidence interval. It also records safety counts and several serious adverse-event terms. Those details describe the study’s question and some of its reported safety information.

The record does not report the numerical result for the primary endpoint. As a result, it is not possible to state how often margin-negative resection occurred, how precise that estimate was, or whether the observed result met any criterion for success. The listed secondary outcomes also lack numerical results in the registry record. The study’s completed status does not supply those missing estimates.

Even if an endpoint estimate were available, the single-group design would limit what it could establish. It could describe outcomes among participants meeting the endpoint definition, but it could not show how those outcomes compare with a concurrent control group. There was no randomized allocation, and masking is listed as none. Thus the record does not support a causal treatment comparison.

The endpoint population also matters. The registry defines the primary rate using participants who underwent laparoscopy and pancreatic resection. That is narrower than the enrolled population. The record does not explain the handling of participants who did not reach resection for other analyses, so the endpoint should not be generalized to all enrolled participants without additional information.

In general, a trial’s findings are interpreted using the outcome estimate, its uncertainty, the analysis population, the design and the completeness of reporting. Here, the numerical primary result, interval limits, outcome analysis details and statistical plan are not reported in the registry record. The record can therefore support a description of the study design and recorded safety counts, but not a conclusion about treatment efficacy or comparative benefit.

14. Why This Trial Matters Statistically

This study illustrates why endpoint definitions and analysis populations matter as much as an endpoint’s name. The primary outcome is described as an R0 resection rate, but the denominator is restricted to participants who underwent laparoscopy and pancreatic resection. That definition makes clear that a reader should distinguish a surgical outcome among participants who reached surgery from an outcome among everyone enrolled. Without the numerical result and analysis details, the size and precision of that estimate remain unknown.

The single-group design also highlights the difference between describing outcomes and estimating a comparative treatment effect. A rate in one group can be clinically relevant as a description of what happened to that group, but it does not establish what would have happened under another approach. Randomized comparisons address a different statistical question. The registry’s design cannot support that direct comparison.

The record further demonstrates the importance of reporting uncertainty. A confidence interval is specified for the primary endpoint, but neither the estimate nor its interval is posted. Naming an uncertainty measure is not enough to evaluate precision. Readers need the estimate, interval limits, denominator and analysis method to understand how stable the finding may be.

Finally, safety counts and outcome definitions are useful but incomplete without information about event collection, follow-up and analysis. The record offers some descriptive safety data but does not post primary outcome results or analysis entries. Statistically, the distinction between what a study planned to measure and what its record reports as observed findings is central to responsible interpretation.

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 principal limitation for interpreting this trial record is that the numerical primary endpoint result is not reported. Although the endpoint is named and a 95% confidence interval is specified, neither the estimate nor the interval limits appear in the registry record. Numerical results for the listed secondary outcomes are also not reported. This prevents assessment of effect magnitude, uncertainty and consistency across outcomes.

The single-group design has no randomized comparator, and masking is listed as none. Any observed outcome would therefore be descriptive rather than a direct estimate of a difference between treatment strategies. The record does not report a statistical analysis plan, sample-size justification, interim analysis approach or analysis entries. Those details cannot be inferred from the phase designation or the completed status.

The primary endpoint applies to participants who underwent laparoscopy and pancreatic resection. How participants who did not proceed to surgery were handled in other analyses is not reported in the registry record. Eligibility criteria, criteria for resectability, outcome-assessment procedures and missing-data handling are also not described in the available record.

The radiotherapy description is incomplete, ending at 3 Gy/. The record therefore does not establish the full radiation schedule. It also does not provide detailed follow-up or endpoint-assessment information beyond the primary timeframe of up to 48 months. Safety reporting includes participant counts and selected serious-event terms, but details such as event timing, severity grading, attribution and deaths are not reported. These limitations restrict interpretation of both efficacy and safety information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Efficacy of Neoadjuvant Chemoradiation for Potentially Resectable Pancreas Cancer — NCT00557492.
• Registry record last updated 2018-09-25; status last verified 2018-08.
• Results first posted 2016-12-12.
• 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 record describes a completed phase II, single-group study of preoperative bevacizumab, gemcitabine and external beam radiotherapy for potentially resectable pancreatic cancer. Enrollment is listed as 59. The primary endpoint is the rate of margin-negative surgical resection, with a 95% confidence interval and a timeframe of up to 48 months. Its definition uses participants who underwent laparoscopy and pancreatic resection.

The registry lists overall survival, progression-free survival, surgical resection rate, radiographic tumor response and serum CA 19-9 response as secondary outcomes. It does not report numerical results for the primary endpoint or these outcomes, and no analysis entries are listed. The safety record reports 10 participants affected by serious adverse events and 50 affected by other adverse events, with 59 at risk in each category. The radiation schedule is incomplete in the record, and details of statistical methods, missing-data handling and analysis populations are not reported.