Radiation Therapy and Chemotherapy in Treating Patients With Stage I Bladder Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Radiation Therapy and Chemotherapy in Treating Patients With Stage I Bladder Cancer (NCT00981656), a na phase 2 study. The primary outcome is Percentage of Participants Free From Radical Cystectomy at 3 Years.

2. Clinical Question

The study concerns a bladder-preserving treatment approach for stage T1 bladder cancer. Its protocol description combines radiation with chemotherapy intended to act as a radiosensitizer. It allows either cisplatin alone or mitomycin with 5-fluorouracil; the registry does not report how many participants received each chemotherapy option.

The primary outcome focuses on whether participants underwent radical cystectomy during the specified follow-up period. It is therefore a measure of remaining free from that procedure, rather than a direct measure of tumor response alone. The registry also lists outcomes concerning disease progression, survival, and bladder cancer-specific death.

Because the study has a single group and no randomized control, its primary question is descriptive: what outcome was observed among the eligible participants who started treatment? The record does not report the primary outcome estimate, so it cannot establish from the posted information what percentage remained cystectomy-free or how precisely that percentage was estimated.

3. Trial Design

This is a phase II study with a single-group model. The registry gives allocation as NA and masking as none. It lists enrollment as 37 and status as completed. The sponsor is the Radiation Therapy Oncology Group. The record lists the start as 2009-11 and primary completion as 2021-03.

The study population is described as patients with stage T1 bladder cancer. Its official title specifies selective bladder-preserving treatment following a thorough transurethral surgical re-staging. The treatment arm is concurrent three-dimensional conformal radiation therapy and radiosensitizing chemotherapy. Chemotherapy could consist of cisplatin alone or the combination of mitomycin and 5-fluorouracil. Protocol treatment was required to begin within 15 weeks after transurethral resection of the tumor.

With no randomized comparator, the design can describe outcomes in the treated group but does not provide a concurrent control for estimating how outcomes might differ under another treatment. Differences from other groups or studies cannot be interpreted as randomized treatment effects on the basis of this trial design alone.

The primary outcome is the percentage of participants free from radical cystectomy at three years from registration. The registry lists secondary outcomes involving distant disease progression, progression to tumor stage T2 or greater, bladder cancer-specific death, and survival. It also records adverse-event information. The detailed statistical analysis plan, eligibility criteria beyond the described population, treatment delivery details, and the reasons for the study's completion timing are not reported in the registry record.

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: Eligible participants who started study treatment

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: Eligible participants who started study treatment

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Participants Free From Radical Cystectomy at 3 Years, measured over Three years from registration.

The primary endpoint is the percentage of participants who did not undergo radical cystectomy within three years from registration. The registry defines the measure as the number of participants without radical cystectomy divided by the number of analyzed participants. The stated analysis population is eligible participants who started study treatment. The endpoint is accompanied by a 97.5% lower bound.

In general, an endpoint based on remaining free from a major procedure can describe whether a treatment strategy is associated with avoiding that procedure over a defined follow-up period. It is distinct from measuring tumor response at a single assessment: the endpoint concerns whether radical cystectomy occurred during the specified period. It does not, by itself, describe all aspects of cancer control, quality of life, or treatment burden.

The denominator matters because the percentage depends on which participants were analyzed. Although the registry specifies the intended population, it does not report the analyzed count or the endpoint value. It also does not explain how participants without complete follow-up were handled or how the confidence bound was calculated. As a result, the endpoint's definition is available, but its observed estimate and precision cannot be evaluated from the registry information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The methods that can be described from the registry record are limited to the design features and endpoint definition it reports. The study is listed as phase II, single group, with no masking and allocation recorded as NA. The primary measure is a percentage, defined using participants who did not undergo radical cystectomy within three years and the number analyzed. The record specifies eligible participants who started study treatment as the analysis population and describes a 97.5% lower bound.

What does a percentage endpoint represent?

In general, a percentage for a binary outcome summarizes the proportion of an analysis group meeting a specified condition. Here the condition is being free from radical cystectomy within the stated follow-up period. The percentage is interpretable only alongside its denominator, outcome definition, and follow-up rules. The registry gives the definition and intended population, but it does not report the analyzed denominator or the observed percentage.

Binary outcomes simplify a complex clinical course into whether an event did or did not occur within a defined period. That can be useful for a clear clinical question, but it does not retain all information about when an event occurred or what happened at other points in follow-up. The record does not describe whether the primary analysis used a simple proportion, a time-to-event method, or another approach to account for follow-up. It would be inappropriate to assume one of these methods from the endpoint title alone.

How should the confidence bound be understood?

In general, a confidence interval expresses sampling uncertainty around an estimate under a specified statistical method. A lower confidence bound gives the lower edge of an interval rather than the point estimate itself. The registry says the primary result was to be presented with a 97.5% lower bound, but does not report the bound, the point estimate, the interval construction, or its assumptions. Without these details, the precision of the primary estimate cannot be assessed.

The confidence level and method should not be inferred from the endpoint wording. The reason for selecting a 97.5% lower bound and whether it relates to any other planned analyses are not reported in the registry record. Nor does the record describe how incomplete follow-up, censoring, or participants who did not start treatment were handled in the primary analysis.

What does the single-group design permit?

In general, a single-group study estimates outcomes among participants receiving the study intervention. It does not create a randomized comparison of outcomes under different treatments. Random assignment can help balance both known and unknown prognostic factors between groups; a single-group design cannot provide that protection. As a result, an observed outcome in this study cannot by itself determine what would have happened to comparable participants under another treatment.

The registry describes the treatment as concurrent three-dimensional conformal radiation therapy with either cisplatin alone or mitomycin and 5-fluorouracil. This is not a comparison of those chemotherapy choices: the record does not report a randomized allocation between them or separate outcome estimates for each. Likewise, the results cannot be attributed to radiation alone, chemotherapy alone, or a particular component from the design information available.

What can the planning assumptions tell readers?

The registry describes a sample-size planning illustration based on the observed effect, not the trial's own design. Its assumptions include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is specified as a fraction of the observed effect. These are planning assumptions, not a report of observed power. The listed trial itself is single group, so equal allocation between two arms describes a hypothetical planning setup rather than the treatment allocation in this study.

In general, sample-size planning asks how many participants would be needed to detect a chosen effect under stated assumptions. Such illustrations depend on the effect size, variability or event rate, significance level, power target, allocation, and analysis method. A planning number does not show that a completed trial had a given probability of detecting an effect, and it does not establish the probability that the result is true. The registry record does not report the trial's original sample-size justification or the statistical design rationale. No specific planning output is stated in the registry record.

What statistical details remain unknown?

The registry record does not report the primary estimate, analyzed denominator, confidence-bound method, handling of missing outcomes, or a detailed statistical analysis plan. It also does not state whether analyses were adjusted for other variables, how follow-up was incorporated, or how deviations from treatment were handled. These omissions prevent an independent assessment of whether the analysis matches the endpoint definition and intended population.

General statistical principles can explain why these details matter, but they cannot fill in the methods used in this trial. In particular, no method should be assigned to the endpoint solely because it is expressed as a percentage or includes a confidence bound.

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("3DCRT + CT")
n      <- c(34)
events <- c(30)
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  3DCRT + CT  34  30  88.2  72.5  96.7  73.4  95.3  73.3  95.2

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures and 1 analysis. The primary outcome concerns freedom from radical cystectomy at three years. The listed secondary outcomes include radical cystectomy at a later time point, distant disease progression, progression to tumor stage T2 or greater, bladder cancer-specific death, and survival. Their names indicate multiple clinical questions, but the registry record does not provide their result values in the registry record for this analysis.

When a study assesses multiple outcomes or makes multiple statistical comparisons, the chance of at least one apparently notable result can increase. In general, multiplicity procedures can control that risk, but the appropriate approach depends on the planned questions and analysis strategy. The registry record does not report whether a multiplicity adjustment was used, whether outcomes were hierarchically ordered, or how the primary and secondary analyses were related. The listing of one analysis does not provide enough detail to determine how many statistical tests or estimates were performed.

The record defines the primary outcome population as eligible participants who started study treatment, but does not state the analyzed number. It does not report missing outcome counts, reasons for missingness, follow-up completeness, or methods used to handle missing data. It also does not describe whether participants were analyzed according to treatment received or another population definition. These details are not reported in the registry record, so the effect of missing data or analysis-population choices cannot be evaluated.

The study is recorded as completed, but completion status does not resolve these reporting gaps. Without the primary estimate, analysis denominator, missing-data approach, and multiplicity strategy, readers cannot assess the robustness or precision of the endpoint findings.

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: urinary tract infection (5.9%), atrial fibrillation (2.9%), duodenal ulcer (2.9%), mucositis oral (2.9%), fever (2.9%).

The adverse-event record lists the 3DCRT + CT group with 34 participants at risk for serious adverse events and 7 affected. For other adverse events, it lists 34 at risk and 33 affected. The record also lists 15 deaths. These are separate registry entries; the registry entries do not explain how the categories relate to one another, whether event categories overlap, or whether deaths were attributed to treatment or disease.

The serious adverse-event terms listed most prominently are urinary tract infection at 5.9%, atrial fibrillation at 2.9%, duodenal ulcer at 2.9%, oral mucositis at 2.9%, fever at 2.9%, and non-cardiac chest pain at 2.9%. The registry provides these as percentages, but does not give additional event-level details in the registry record. They should be read as descriptive entries, not evidence that treatment caused the events.

In general, adverse-event counts describe events recorded under a study's reporting process. Interpretation depends on definitions, observation periods, severity grading, attribution, and completeness of follow-up. Those details are not reported in the registry record. The counts also do not provide a comparison with an untreated or alternative-treatment group, so they cannot establish relative safety.

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

The registry record establishes that a phase II, single-group study evaluated concurrent three-dimensional conformal radiation therapy and radiosensitizing chemotherapy for stage T1 bladder cancer. It identifies freedom from radical cystectomy at three years from registration as the primary outcome and defines the intended analysis population. It also lists outcomes covering progression and survival, and records adverse-event information.

Those details describe the question and framework of the study, not the answer to its primary question. The primary outcome estimate, the 97.5% lower bound, and the number analyzed are not reported in the registry information available for this analysis. Consequently, the posted information does not show what percentage of the analysis population remained free from radical cystectomy or how precise that estimate was.

Even if an outcome estimate were available, the single-group design would support a description of outcomes in the treated group, not a randomized estimate of what treatment changed relative to an alternative. No control group is identified. The study also allowed more than one chemotherapy regimen, and the record does not report separate outcome estimates by regimen. It therefore does not support conclusions about which treatment component or chemotherapy option accounts for any observed outcome.

The adverse-event entries provide descriptive counts and percentages. They do not, on their own, demonstrate treatment causation or comparative safety. The registry entries do not report enough detail about attribution, event timing, missing safety information, or a comparison group to support such judgments.

In general, the meaning of a clinical trial result depends on the outcome estimate, its uncertainty, the analysis population, follow-up, and design. Here, the record supplies a useful description of the intended endpoint and study structure but not the primary result needed to quantify the observed outcome. No claim that the treatment does or does not work follows in the registry record reported.

14. Why This Trial Matters Statistically

This trial raises a statistically important question about how to describe an outcome when a study has one treatment group and a clinically concrete endpoint. Freedom from radical cystectomy at three years is defined in a way that readers can connect to the study's bladder-preserving aim. The registry also makes clear that the measure concerns eligible participants who started treatment, a population definition that should be distinguished from the enrollment entry.

The design illustrates the boundary between estimating an outcome and estimating a treatment effect. A single-group percentage can characterize what happened among treated participants, but it lacks a randomized control group for separating treatment effects from other influences. That distinction matters when interpreting any apparent success or failure and when comparing results with other settings.

It also shows why a point estimate and its uncertainty are both needed. The registry describes a 97.5% lower bound, but the estimate and bound are not reported in the registry record for this analysis. Without them, readers cannot assess the magnitude or precision of the primary result. Without the analyzed denominator and missing-data approach, they also cannot evaluate the basis of the estimate.

Finally, the study includes multiple secondary outcomes and adverse-event entries. Their presence broadens the range of questions a reader may want to ask, while making clear that reporting of results, analysis populations, and multiplicity methods is essential. The record's design and endpoint definitions are informative, but they cannot replace numerical outcome reporting and a transparent account of analysis methods.

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 central limitation for interpreting this trial from the registry record is that the primary outcome result is not reported in the registry record. The stated percentage, its 97.5% lower bound, and the analyzed denominator are missing. This prevents assessment of both the observed outcome and its precision.

The single-group design has no randomized control arm. It can describe outcomes in the treated group, but does not provide a like-for-like basis for attributing differences to treatment. The record also allows either cisplatin alone or mitomycin with 5-fluorouracil, without reporting separate results for those options. The registry entries therefore do not permit comparison of the chemotherapy choices or isolation of the effects of individual treatment components.

The registry lists enrollment as 37, while defining the primary analysis population as eligible participants who started treatment. It does not report the number who met that analysis definition, the number analyzed, or the handling of participants with missing follow-up. The implications of exclusions, incomplete outcome ascertainment, or analysis-population choices cannot be evaluated.

The statistical methods are incompletely described. The method for calculating the lower confidence bound, handling follow-up, and addressing multiplicity is not reported in the registry record. The registry entries also do not provide numerical results for the listed secondary outcomes. Adverse-event counts are available, but details about attribution, timing, definitions, and overlap are not reported. These limits constrain interpretation of efficacy-related outcomes and safety information alike.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Radiation Therapy and Chemotherapy in Treating Patients With Stage I Bladder Cancer — NCT00981656.
• Registry record last updated 2024-09-19; status last verified 2023-08.
• Results first posted 2022-04-25.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT00981656 is a completed phase II, single-group study sponsored by the Radiation Therapy Oncology Group. The registry lists enrollment as 37, gives the start as 2009-11 and primary completion as 2021-03, and records no masking and allocation as NA.

The intervention was concurrent three-dimensional conformal radiation therapy with radiosensitizing chemotherapy, consisting of cisplatin alone or mitomycin with 5-fluorouracil. The primary outcome was the percentage free from radical cystectomy at three years from registration among eligible participants who started study treatment. A 97.5% lower bound was specified.

The primary outcome estimate and analyzed denominator are not reported in the registry record. Secondary outcomes concern progression and survival. The adverse-event entry lists 34 at risk and 7 affected for serious events, 34 at risk and 33 affected for other events, and 15 deaths. These descriptive entries do not establish causation or comparative effects.