Irinotecan and Carboplatin in Treating Patients With Metastatic or Recurrent Small Cell Lung Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Irinotecan and Carboplatin in Treating Patients With Metastatic or Recurrent Small Cell Lung Cancer (NCT00387660), a non-randomized phase 2 study. The primary outcome is Overall Response Rate.

2. Clinical Question

The central question is therefore descriptive: what overall response was recorded among the participants who met the endpoint’s measurement requirement? The endpoint definition specifies disappearance of all target lesions for complete response and a decrease of at least 30% in the sum of the longest diameters of target lesions for partial response. Overall response combines those two categories.

This design does not estimate a randomized treatment contrast. In particular, the metastatic and relapsed descriptions do not establish that one group is a control for the other, and the record explicitly warns that the arms are not a like-for-like comparison. Any difference between such groups could reflect differences in the participants or disease setting, not necessarily the regimen. The registry does not report an overall response estimate, its denominator, or an uncertainty interval, so the size and precision of the response cannot be evaluated from the recorded primary outcome.

3. Trial Design

The registry describes NCT00387660 as a phase II study of irinotecan and carboplatin for metastatic or relapsed small-cell lung cancer. It lists the allocation as nonrandomized, the model as single-group, and masking as none. Enrollment was 80, and the study status is completed. The record gives a start date of 2001-10 and a primary completion date of 2008-08.

The treatment descriptions distinguish metastatic and relapsed SCLC. For metastatic SCLC, the listed regimen is irinotecan 200 mg/m2 intravenously every 21 days plus carboplatin AUC = 5 mg/ml x min intravenously every 21 days for 6 cycles. For relapsed SCLC, irinotecan is listed at 150 mg/m2 intravenously every 21 days with carboplatin at AUC = 5 mg/ml x min intravenously every 21 days for 6 cycles. The registry does not state how participants were assigned to these descriptions, and it does not identify a control treatment.

The record’s single-group designation and its two arm labels should be read alongside its explicit warning: this is not a randomized comparison, and the arms are not a like-for-like control comparison. The labels alone do not establish a comparative design. No masking means the registry does not describe blinded treatment or assessment.

The primary outcome is overall response rate, assessed by radiographic techniques under the stated RECIST criteria. Its timeframe is up to 36 months, while its analysis population is participants with response measurements at baseline and after 2 cycles. Secondary outcomes listed are median survival and the number of participants with toxicity. Numerical results for these outcomes, except the adverse-event counts and terms described separately, are not reported in the registry record. The record does not report the protocol’s sample-size justification or a detailed statistical analysis plan.

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

Analysis population for the primary outcome, as defined in the registry: All participants for whom response evaluation measurements were recorded at Baseline and after 2 cycles.

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 Overall Response Rate, measured over Up to 36 months.

Overall response rate is the proportion of participants classified as having a complete or partial response. The registry defines complete response as disappearance of all target lesions. A partial response requires at least a 30% decrease in the sum of the longest diameter of target lesions. The two categories are combined to form overall response, using radiographic assessment under the stated Response Evaluation Criteria in Solid Tumors criteria.

This endpoint is used to summarize tumor response during treatment without requiring a survival outcome. It translates lesion measurements into clinically interpretable response categories, then expresses the combined categories as a percentage of the evaluated population. As a general statistical point, a percentage is meaningful only alongside its denominator: the denominator clarifies how many participants contributed evaluable measurements, while an uncertainty interval would show the range of values compatible with the observed data under the chosen method.

The registry specifies that the primary endpoint population includes participants with response evaluation measurements recorded both at baseline and after 2 cycles. This requirement matters because the endpoint is not necessarily based on every enrolled participant. The record does not give the number with the required measurements, the number classified as responders, the resulting percentage, or an uncertainty interval. Thus, the endpoint is defined, but its numerical result is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information available describes the outcome, study structure, and a general planning illustration. It does not report the methods actually used to analyze the primary endpoint. The registry lists zero analyses, and a detailed analysis plan is not reported in the registry record. The following concepts explain how this kind of endpoint is commonly interpreted; they should not be read as claims about methods used in this study.

What does a response percentage represent?

For a binary outcome such as response, each evaluated participant is classified into a category such as responder or not responder, according to the endpoint definition. The response percentage summarizes the number classified as responders relative to the number evaluated. In general, this percentage is a sample estimate of the response proportion in the population represented by the study participants. Its interpretation depends on the endpoint rules being applied consistently and on knowing who was included in the denominator.

Here the registry’s endpoint population consists of participants with response measurements at baseline and after 2 cycles. This is not automatically the same as all enrolled participants. A response percentage based on an evaluable subset could differ from one calculated using all enrolled participants, particularly if reasons for missing measurements are related to disease status, treatment experience, or follow-up. The registry does not report the size of the endpoint population or how participants without the specified measurements were handled.

Why is an uncertainty interval useful?

As a general concept, a confidence interval describes the uncertainty associated with an estimate under a statistical model and method. For a response proportion, it helps readers judge how precisely the observed percentage estimates the underlying response rate. A point estimate alone does not show that precision. The registry does not report a confidence interval for overall response, so precision cannot be assessed from the posted primary outcome.

Different methods for intervals around proportions can have different properties, especially when the evaluated group is small or the response proportion is near the extremes. Which method was used is not reported in the registry record. It would therefore be inappropriate to attribute a particular interval procedure to this trial or to reconstruct an interval from an outcome estimate that is itself absent.

What can and cannot be inferred from this design?

Random allocation, when used, can help balance measured and unmeasured prognostic factors between treatment groups on average. This record describes nonrandomized allocation and a single-group model, and it warns that its arms are not a like-for-like control comparison. As a general statistical principle, nonrandomized group comparisons may be affected by differences in participant characteristics, disease setting, or other factors. A contrast between the metastatic and relapsed descriptions would not by itself isolate a treatment effect, particularly because the registry describes different irinotecan doses and does not describe random assignment.

Masking is listed as none. In general, lack of masking can affect assessment or reporting when outcomes involve judgment. The registry says response was assessed using radiographic techniques and specified criteria, but it does not report further details about assessor procedures. No additional conclusions about bias or its magnitude can be drawn from the record.

How should the planning illustration be read?

The record describes sample-size calculations as planning illustrations computed from the observed effect, rather than as the trial’s own design. The stated assumptions include 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 fraction of the observed effect. For outcomes other than time-to-event outcomes, such calculations are expressed as participants per arm. These are hypothetical planning assumptions, not evidence that the trial used a two-arm randomized design.

Because the actual study is described as nonrandomized and single-group, the equal-allocation assumption should not be mistaken for the trial’s allocation scheme. The record does not report the protocol’s sample-size justification, the planning target used when the study was designed, or a detailed statistical plan. A planning illustration based on an observed effect also does not establish the power of a completed study. It is not observed power, and it cannot replace a confidence interval or a reported outcome estimate.

For a binary outcome, the number of participants needed in a planning calculation depends on assumptions about the response proportion, the effect to detect, the significance level, power target, allocation, and analysis method. This is a general explanation; the registry does not report enough design details to verify a protocol calculation. Any calculated sample-size illustration should be treated as conditional on its stated assumptions, not as a trial result or proof that the study was adequately sized.

Why do endpoint definitions and analysis populations matter?

The response criteria determine how radiographic findings become response categories. Changing the criteria or assessment timing can change who is counted as a responder. Similarly, the endpoint’s stated requirement for baseline and post-cycle measurements defines who can contribute to its assessment. Reporting both the numerator and denominator, along with missing-data handling and an uncertainty interval, supports transparent interpretation. Those numerical details and handling rules are not reported in the registry record for the primary outcome.

The record also names median survival and toxicity as secondary outcomes. Time-to-event analysis can account for differing follow-up and censoring under specified assumptions, but the registry does not provide a survival result or analysis details. It would be speculative to infer which survival method, censoring rule, or adjustment procedure was used. The same caution applies to toxicity: the listed counts describe recorded events, but the record does not supply a complete analysis plan or definitions for every category.

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("Arm A", "Arm B")
n      <- c(34, 38)
events <- c(22, 19)
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  Arm A  34  22  64.7  46.5  80.3  47.9  78.5  47.8  78.5
ARM  Arm B  38  19  50.0  33.4  66.6  34.8  65.2  34.8  65.2

11. Multiplicity, Missing Data and Analysis Populations

The registry names one primary outcome, overall response rate, and two secondary outcomes: median survival and number of participants with toxicity. It does not report a multiplicity strategy for interpreting several outcomes or tests together. In general, testing multiple hypotheses can increase the chance of at least one apparently notable result arising by chance; a prespecified approach can clarify how that risk is handled. Whether such a plan existed for this study is not reported in the registry record.

The record lists zero analyses. This means that statistical analysis results are not recorded there; it does not establish which analyses may have been conducted outside the registry. No p-value, adjustment method, covariate model, or inferential test for the primary outcome is reported. The protocol’s analysis plan and any interim analyses are not reported in the registry record.

Missing data are especially relevant because the primary endpoint population requires response measurements at baseline and after 2 cycles. The registry does not state how many enrolled participants lacked one or both measurements, why measurements were unavailable, or how missing assessments were handled. In general, excluding participants without evaluable assessments can affect interpretation if missingness is related to response or participant status. No particular missing-data mechanism or procedure can be inferred.

The registry also does not report whether all enrolled participants were included in an intention-to-treat analysis, whether the primary analysis used an evaluable population, or how deviations from the treatment regimen were treated. The endpoint description identifies the measurement-based population, but it does not provide the denominator or a full analysis-population definition. Those omissions limit reproducibility and make it difficult to compare the stated endpoint with a result calculated under a different population rule.

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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: dyspnea (2.5%), vomiting (2.5%), nausea (2.5%).

The registry lists two groups, Arm A and Arm B, with 40 participants at risk for serious events in each group. It reports 2 participants affected by serious adverse events in each group. These are counts, not rates adjusted for exposure time, and the record does not provide a separate duration of observation for these safety summaries.

For other adverse events, the record lists 40 participants at risk and 40 affected in each group. These figures are recorded separately from the serious-event counts. They should not be added together: the registry does not state whether participants with serious events are also included in the other-event category or how the categories relate.

The listed serious-event terms are Dyspnea, Vomiting, and Nausea, each reported as 2.5%. The record does not give further detail about event severity beyond the serious-event classification, timing, duration, recurrence, or attribution to treatment. It also does not report death counts in these groups. The serious-event counts and selected terms provide a limited descriptive safety account, not a complete comparison of risk between treatment groups.

Because the design is nonrandomized and the arms are not described as like-for-like controls, differences in these safety figures would not by themselves establish a causal treatment difference. The record does not report enough information to compare exposure or follow-up between groups.

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

The record establishes that a phase II study evaluated irinotecan with carboplatin in metastatic or recurrent small-cell lung cancer and defined overall response using radiographic criteria. It also identifies the endpoint population and treatment descriptions. These details clarify what the study intended to assess, but they do not provide the numerical primary result.

The registry does not report the overall response percentage, the number of responders, the number of participants evaluated for response, or a confidence interval. It therefore cannot show how large the response estimate was or how precisely it was measured. The named secondary outcomes of median survival and toxicity also lack numerical outcome results in the registry record, apart from the listed adverse-event information.

The record does not establish whether the regimen is better or worse than another treatment. It describes a nonrandomized, single-group study and explicitly cautions that the arms are not a like-for-like control comparison. A comparison across the metastatic and relapsed descriptions would not be equivalent to a randomized comparison, and the registry does not report a control group.

As a general principle, a response outcome is one part of the evidence about a treatment regimen. It does not, by itself, capture duration of response, survival, toxicity in full, or how outcomes compare with alternatives. Those questions require complete outcome reporting and an appropriate comparative design. The current record supports a description of the planned endpoint and recorded safety counts, but not a numerical estimate of overall response or a comparative conclusion.

The study’s completed status should not be confused with complete public reporting of all outcomes. The registry record documents completion and enrollment, while leaving the primary response result and other key statistical details unreported. Any interpretation should remain within that distinction.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of why a clearly defined endpoint and a reported numerical result are both necessary. The registry specifies the response categories, radiographic assessment, timeframe, and measurement requirements. Those details make the intended outcome understandable. However, without the response count, denominator, and estimate, readers cannot assess the result’s magnitude or precision.

The record also illustrates the importance of distinguishing a single-group or nonrandomized study from a randomized comparison. The registry labels the study nonrandomized and single-group, and warns that the arms are not like-for-like controls. Group labels or different regimen descriptions do not alone create a valid treatment contrast. This matters when interpreting both response and safety information.

Another statistical consideration is the analysis population. The endpoint is defined for participants with measurements at baseline and after 2 cycles, whereas enrollment is reported separately. Reporting the number assessed and the handling of participants without required measurements would help readers understand the denominator and evaluate possible selection effects. Those details are not reported in the registry record.

Finally, planning illustrations and observed trial results answer different questions. A calculation based on an observed effect under stated assumptions is not a substitute for the study’s design rationale, a prespecified analysis plan, or an uncertainty interval around the actual result. The registry does not report its protocol sample-size justification or detailed statistical methods. Together, these omissions limit independent evaluation even though the endpoint and broad design are described.

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 main trial-specific limitation in the registry record is the absence of a numerical overall response result. There is no response percentage, responder count, evaluable denominator, or confidence interval. Without these, the primary endpoint cannot be quantitatively interpreted.

The endpoint population is defined by having measurements at baseline and after 2 cycles, but the record does not report how many participants met that definition. It also does not explain how participants without those measurements were handled or whether other analysis populations were used. These omissions prevent assessment of how the analyzed population relates to the total enrollment of 80.

The nonrandomized, single-group design does not provide a randomized control comparison. The registry specifically states that the arms are not a like-for-like comparison. The regimen descriptions distinguish metastatic and relapsed disease and list different irinotecan doses, but the record does not explain allocation to these descriptions or report a basis for causal comparisons between them.

Statistical analysis methods, interim analyses, multiplicity handling, and the protocol’s sample-size justification are not reported in the registry record. The record’s planning assumptions should not be read as the actual trial design or as observed power. Secondary outcome names are listed, but numerical survival results are not reported. Safety reporting is limited to the listed counts and selected serious-event terms; deaths and additional detail about exposure, follow-up, and event attribution are not reported.

These limitations concern what can be interpreted from the registry record. They do not establish that unreported analyses or information do not exist elsewhere; they mean those details are not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Irinotecan and Carboplatin in Treating Patients With Metastatic or Recurrent Small Cell Lung Cancer — NCT00387660.
• Registry record last updated 2018-01-10; status last verified 2018-01.
• Results first posted 2017-05-01.
• 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

NCT00387660 is a completed phase II, nonrandomized, single-group study of irinotecan and carboplatin in metastatic or recurrent small-cell lung cancer. Enrollment was 80. The registry describes no masking and warns that the arms are not a like-for-like control comparison.

The primary endpoint is overall response rate under RECIST criteria, for participants with baseline and post-cycle-2 response measurements. The numerical response result and its precision are not reported in the registry record. Median survival and number of participants with toxicity are listed as secondary outcomes; numerical survival results are not reported. Safety entries include serious-event counts and selected serious-event terms, but do not constitute a complete comparative safety analysis.

The record does not report the protocol’s sample-size justification or detailed statistical analysis plan. Interpretation is therefore limited to the study design, endpoint definition, and recorded safety information.