Gemcitabine/Cisplatin for Resected Pancreas Cancer: Establishing the Role of ERCC1 in Treatment Decision: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Gemcitabine/Cisplatin for Resected Pancreas Cancer: Establishing the Role of ERCC1 in Treatment Decision (NCT01188109), a na phase 2 study. The primary outcome is Recurrence-free Survival as Measured by CT Scan.

2. Clinical Question

These questions involve different forms of evidence. A single-group treatment study can describe the recurrence-free survival observed among people receiving the combination, but without a concurrent comparison group it cannot isolate the effect of the combination from other explanations. The biomarker question is also about treatment selection: to establish that a marker identifies people who benefit differently from alternative treatments, the evidence needs to distinguish marker-related outcome patterns from the effect of treatment itself. The registry record describes an ERCC1 expression assessment but does not report a treatment-by-marker comparison.

3. Trial Design

This is a phase 2, single-group study sponsored by Emory University. The registry lists allocation as NA and masking as none. The listed arm is Gemcitabine / Cisplatin, with both drugs given as adjuvant therapy following resection. There is no separate arm receiving gemcitabine alone, even though the study summary identifies comparison with gemcitabine alone as a question of interest. The design therefore does not provide a randomized, concurrent treatment comparison.

The registry lists enrollment as 25. The study start is recorded as 2010-07, the primary completion as 2015-07, and the status as terminated. The reason for termination, the number of people who completed follow-up, and details of any changes to the study are not reported in the registry record. The listed dates describe the registry timeline; they do not establish why the study ended or how much follow-up was available for each participant.

The primary outcome is recurrence-free survival, with the measure specified as a median and a 95% confidence interval. Follow-up is described using radiologic assessment and CA19-9. The outcome timeframe states assessment every 3 months and then every 6 months for 2 more years after resection. The outcome description says patients were followed with CT or MRI and CA19-9 every 3 months for the first 3 years after resection, and subsequently underwent imaging every 6 months. The record does not explain the difference in wording between these schedule descriptions.

ERCC1 expression assessed by immunohistochemistry is listed as a secondary outcome. The registry does not report details of the assay, a classification rule, or how the result was intended to guide treatment. It also does not report protocol-level statistical methods or a sample-size justification. Because this is a single-group study, its outcome estimates should be read as descriptions of the treated group, not as estimates of a treatment contrast.

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: Twenty-five patients were initially enrolled. Three patients were thereafter excluded; two were diagnosed with secondary malignancies (primary lung adenocarcinoma and thyroid cancer), and one had a diagnosis of cholangiocarcinoma on final surgical pathology.

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 Recurrence-free Survival as Measured by CT Scan, measured over Every 3 months and then every 6 months for 2 more years after resection.

Recurrence-free survival is a time-to-event outcome: it concerns the time until recurrence, with the exact event definition and handling of deaths or other events needing to be specified in the study methods. The registry names the primary outcome as recurrence-free survival measured by CT scan and specifies the median and a 95% confidence interval. The outcome description also includes MRI and CA19-9 in the follow-up assessments. The precise operational definition of recurrence, the time origin, and the censoring rules are not reported in the registry record.

In general, time-to-event outcomes are useful when the timing of an event matters and follow-up can vary among participants. A median is the point in the outcome distribution at which the estimated proportion remaining event-free reaches the midpoint. Its confidence interval communicates uncertainty in that estimate; it is not a range that contains every participant's outcome. The interval's width depends on the amount and timing of event information as well as the analysis method.

The registry reports no numerical median or confidence limits for recurrence-free survival. Consequently, the endpoint definition and intended summary can be described, but the observed time-to-event result and its precision cannot be evaluated from the registry record. The listed monitoring schedule does not itself establish how many recurrences occurred or how completely outcomes were observed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods determine how observations become estimates and how much uncertainty accompanies those estimates. The registry record identifies the primary outcome and its intended summary, but does not report the detailed analysis plan, the event definition, or the numerical endpoint result. The following explanations are general and clarify what the named statistical summaries would mean without filling in missing trial results.

What does a median time-to-event result describe?

For a time-to-event outcome, the median is a summary of the estimated distribution of time until the event. It does not describe the timing for every individual and is not the same as an average. A median can remain unevaluable if the observed follow-up does not establish the midpoint of the event-time distribution. The registry specifies a median for recurrence-free survival but does not report the estimate or the information needed to assess how it was obtained.

People may have different lengths of follow-up. Some may not have a recorded recurrence by the end of their observation, or their follow-up may end for another reason. Time-to-event methods can retain information from such observations through censoring, provided the assumptions and censoring rules are appropriate. The registry record does not report its censoring rules, the number of events, or the amount of follow-up. Those omissions prevent a reader from checking the event-time analysis in detail.

What does a confidence interval add?

A confidence interval expresses uncertainty about an estimated quantity under the analysis method. For the stated median, the 95% confidence interval would indicate the range of values compatible with the data and method at that confidence level. It does not show the range of individual outcomes and does not guarantee that a particular interval contains the true value. Precision is often limited when event information is sparse, but the event information for this study is not reported in the registry record. The interval itself is also not reported, so its width and precision cannot be assessed.

Why does the single-group structure matter?

A single-group design can describe outcomes among people who receive the recorded regimen. It does not directly estimate a contrast between that regimen and gemcitabine alone, because no separate gemcitabine-alone arm is listed. In general, a treatment contrast requires outcomes under more than one treatment condition and a design or analysis that supports a fair comparison. Without a concurrent comparator, differences from an external reference may reflect differences in eligibility, disease characteristics, supportive care, assessment schedules, or follow-up rather than treatment.

The allocation entry is NA, and masking is listed as none. These entries describe features of the recorded design; they do not establish what procedures were used for outcome assessment or whether assessors knew treatment information. No further details about assessment masking are reported. The single-group structure also means that the primary endpoint cannot answer the comparative question in the study summary on its own.

What is the role of the biomarker assessment?

ERCC1 expression is listed as a secondary outcome assessed by immunohistochemistry. In general, a biomarker may be prognostic if it is associated with outcomes, and predictive if it identifies different effects of alternative treatments. Showing a predictive role requires evidence that treatment effects differ according to marker status. Observing outcomes for marker-defined groups when everyone receives the same regimen would not, by itself, separate a predictive pattern from a prognostic association. The registry does not report the assay classification, marker results, or an analysis comparing treatment effects by ERCC1 status.

How should planning calculations be read?

The planning assumptions describe an illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. For time-to-event outcomes, the assumptions specify a total number of events; for other outcomes, they specify participants per arm. These are planning conventions, not a description of this study's single-group design or proof that the study had a particular probability of detecting an effect.

Such illustrations are sensitive to the effect used as a reference and to the assumptions behind the calculation. They do not establish what effect was prespecified in the protocol, whether an alternative design was considered, or whether the trial was adequately powered. The registry record does not report a protocol sample-size justification, and it does not provide a numerical primary endpoint result from which to interpret an observed-effect-based illustration. Sample-size planning is not observed power: power is a prospective design quantity under stated assumptions, whereas an observed result and its uncertainty should be evaluated directly.

Over-dispersion is a general issue for count outcomes when variability exceeds what a simple model assumes. It can make standard errors too small if ignored. The primary endpoint is time-to-event, not a count outcome, and the registry does not report an over-dispersion analysis. The relevant general concern for the listed endpoint is whether its event definition, follow-up, censoring, and analysis method are adequately described; those details are not reported.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures: recurrence-free survival as the primary outcome and immunohistochemistry to determine ERCC1 expression as a secondary outcome. It lists no analyses. The record does not report a hierarchy of secondary outcomes, a multiplicity adjustment, or how any exploratory analyses would be distinguished from confirmatory analyses.

In general, multiplicity arises when several outcomes, subgroups, time points, or hypotheses are tested. Looking across many tests can increase the chance that at least one result appears notable by chance. A prespecified testing strategy can help readers understand which findings were primary and how uncertainty was handled. Since an analysis plan is not reported, the registry record does not show whether such a strategy was specified or used. This does not establish that no analysis was performed; it means the analyses are not reported in the record.

Missing-data methods and analysis populations are also not reported in the registry record. The record does not specify whether the primary analysis included all enrolled participants, those who received treatment, or another defined group. It does not describe how incomplete follow-up, missing imaging, or unavailable ERCC1 results were handled. For a time-to-event endpoint, the treatment of censored observations and losses to follow-up is important to interpretation, but the registry does not report those procedures.

Interim analyses, stopping rules, and any adjustments connected with repeated analyses are not reported in the registry record. The status is terminated, but the record does not give a reason or connect termination to any interim finding. Without a documented plan and analysis results, neither multiplicity control nor the handling of missing information can be evaluated.

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: thrombocytopenia (4.5%), neutropenia (4.5%), pulmonary embolus (4.5%).

The registry reports adverse-event information for the Gemcitabine / Cisplatin arm. The serious adverse-event entry lists 22 at risk and 2 affected. The other adverse-event entry lists 22 at risk and 11 affected. These are separate reported categories; the record does not explain their overlap or provide enough detail to infer a combined count.

The listed top serious terms are thrombocytopenia, neutropenia, and pulmonary embolus, each reported as 4.5%. These percentages should be read as registry entries, not as comparative risk estimates. No separate treatment arm is listed, so the figures cannot establish how the event frequency compares with gemcitabine alone or another regimen. The record also does not report event severity grades, timing, duration, relatedness assessments, or individual-level detail.

In general, adverse-event counts and percentages describe events recorded under specific definitions and observation procedures. Their interpretation depends on the population monitored, the follow-up period, and whether events were actively solicited or reported in another way. The registry information does not provide all of those details. The status of the study as terminated does not, by itself, indicate that a safety concern caused termination; the reason is not reported in the registry record.

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

The registry establishes that this was a phase 2, single-group study of adjuvant gemcitabine and cisplatin after resection of pancreatic cancer. It identifies recurrence-free survival as the primary outcome, specifies a median and a 95% confidence interval, and lists ERCC1 expression by immunohistochemistry as a secondary outcome. It also records adverse-event summaries for the treatment arm. These details describe the study's scope and planned measurements.

The record does not report a numerical recurrence-free survival result, a confidence interval, or a treatment comparison. It therefore cannot show from the posted information how long recurrence-free survival was in the treated group or how precisely it was estimated. The registry also does not report ERCC1 results or evidence that the marker identifies people who benefit differently from alternative treatments.

The design cannot answer the comparison with gemcitabine alone raised in the study summary because no separate gemcitabine-alone arm is listed. A single-group outcome is not a randomized estimate of the difference between treatments. Nor can the adverse-event figures establish comparative safety in the absence of another arm and fuller methods information.

These limitations do not mean that the study had no value. A study can describe feasibility, collect outcome information, and explore biomarker measurement. But the registry entries alone do not establish a treatment effect, a clinically useful marker, or a reason for termination. Those conclusions require results and methods that are not reported in the registry record. Any planning illustration should be interpreted as a design calculation, not as evidence that an effect was detected or missed.

13. Why This Trial Matters Statistically

This trial illustrates the difference between a scientific question and the comparison a design can estimate. The study summary asks both whether a tumor marker can inform treatment choice and whether combination chemotherapy offers benefit compared with gemcitabine alone. The recorded design lists only the combination arm. It can describe outcomes for that group, but it does not provide the direct treatment contrast needed to estimate the incremental effect of adding cisplatin.

The distinction also matters for biomarker research. A marker associated with recurrence-free survival among people receiving one regimen is not automatically a marker that predicts which regimen is preferable. Prediction concerns differences in treatment effect across marker status, and the registry does not report the alternative-treatment comparison needed to assess that question. The listed ERCC1 assessment is a measurement plan, not evidence of a treatment-selection rule.

The record also shows why endpoint definitions and analysis details matter. Recurrence-free survival depends on how recurrence is defined, when follow-up begins, how censoring is handled, and how outcomes are assessed. The registry describes imaging and CA19-9 follow-up but does not provide all analysis details or the numerical endpoint result. Without those, readers cannot assess the estimate or its precision.

Finally, transparent reporting of analyses, missing-data procedures, and reasons for study termination helps readers distinguish an incomplete registry entry from a study with a particular result. The status is terminated, and the record lists no analyses; neither fact alone explains what occurred. The statistical lesson is to separate what the design could estimate, what the registry reports, and what remains unknown.

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.

Interpretation is limited first by the single-group design. The study summary includes a question about combination therapy versus gemcitabine alone, but the registry lists no gemcitabine-alone arm. A direct comparative treatment effect cannot be estimated from the recorded design. The allocation entry is NA, and no randomized comparison is described.

The primary endpoint is named and its summary measure is specified, but the numerical median and 95% confidence interval are not reported. The registry does not state the recurrence definition, time origin, censoring rules, number of events, or duration and completeness of follow-up. Its timeframe wording and outcome-description schedule are not identical, and the record does not explain the difference.

The ERCC1 assessment is listed without assay details, classification criteria, results, or a treatment-by-marker analysis. Analysis populations, missing-data procedures, multiplicity handling, interim analyses, and a statistical analysis plan are not reported in the registry record. The record lists no analyses, which does not establish whether analyses occurred outside the posted record.

Enrollment is listed as 25, but the registry does not report participant flow or the number included in each outcome analysis. The study status is terminated, but the reason is not reported. Adverse-event summaries lack details on grading, timing, relatedness, and overlap between categories. Together, these gaps prevent a full appraisal of efficacy estimates, precision, biomarker interpretation, and comparative safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Gemcitabine/Cisplatin for Resected Pancreas Cancer: Establishing the Role of ERCC1 in Treatment Decision — NCT01188109.
• Registry record last updated 2016-09-28; status last verified 2016-08.
• Results first posted 2016-08-09.
• 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

NCT01188109 is a phase 2, single-group study sponsored by Emory University of gemcitabine and cisplatin as adjuvant therapy after resection of pancreatic cancer. The registry lists enrollment as 25, allocation as NA, masking as none, and status as terminated. The recorded study dates are 2010-07 for start and 2015-07 for primary completion.

The primary outcome is recurrence-free survival, summarized as a median with a 95% confidence interval. ERCC1 expression assessed by immunohistochemistry is listed as a secondary outcome. The registry does not report a numerical primary endpoint result, ERCC1 findings, or a treatment-group comparison. It lists adverse-event summaries for the single arm and no analyses. The reason for termination, detailed analysis methods, missing-data procedures, and analysis populations are not reported in the registry record.