This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Longer-term Recurrence Rates in Patients With Bladder Cancer After Hexvix (Cysview)Fluorescence Cystoscopy/TURB (NCT01166230), a registered phase not stated study. The primary outcome is Recurrence Free Survival.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01166230 |
| Phase | Phase not stated |
| Condition | Bladder Cancer |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 551 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Photocure |
| Results posted | Yes |
2. Clinical Question
Population
Patients with non-invasive papillary bladder cancer (Ta/T1) who had been included in the previously completed clinical study PCB305/04. The primary endpoint population is described as intention-to-treat (ITT). The registry record states enrollment of 551, but does not report how many patients contributed to each follow-up group or to the endpoint analysis.
Intervention
Hexvix (Cysview) fluorescence cystoscopy with transurethral resection of the bladder (TURB). The study description frames the question around whether improved initial detection and resection might be followed by longer-term differences in recurrence.
Comparator
White-light cystoscopy with TURB. The registry describes the groups as patients with Ta/T1 assigned to Hexvix cystoscopy or white-light cystoscopy in the previously completed study. This follow-up is described as retrospective and non-interventional; allocation for the follow-up comparison is not stated in the registry record.
Primary question
What was recurrence-free survival, measured as a median with a 95% confidence interval, in the ITT population followed for up to 4.5 years? The study was intended to assess longer-term recurrence after the two cystoscopy/TURB approaches. The registry record does not report the median estimates, their confidence intervals, or a numerical comparison between groups.
3. Trial Design
This is an open, non-interventional, retrospective, comparative, multicenter follow-up study. It concerns patients included in the previously completed clinical study PCB305/04 and examines longer-term recurrence after Hexvix (Cysview) fluorescence cystoscopy/TURB or white-light cystoscopy/TURB. The registry lists bladder cancer as the condition and describes the relevant patients as having non-invasive papillary disease, Ta/T1.
The two follow-up groups are described by their assignment in the earlier study: patients with Ta/T1 randomized to Hexvix cystoscopy and patients with Ta/T1 randomized to white-light cystoscopy. That description does not make the present follow-up a randomized trial. The registry characterizes the current study as retrospective and non-interventional, and the allocation method for this comparison is not stated. The registry also cautions that the arms are not a like-for-like control comparison. Consequently, an apparent group difference should not automatically be interpreted as a causal treatment effect.
The registry reports enrollment of 551 and status as completed. It lists a start in 2010-06 and primary completion in 2010-12. The primary endpoint is recurrence-free survival in the ITT population, expressed as a median with a 95% confidence interval, with a timeframe of up to 4.5 years. Rate of progression is listed as a secondary outcome. The record does not describe the follow-up schedule, the methods used to ascertain recurrence, or the analysis procedures in enough detail to evaluate them.
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
| Stage | Patients With Ta/T1, Randomized to White Light Cystoscopy | Patients With Ta/T1 Randomized to Hexvix Cystoscopy |
|---|---|---|
| STARTED | 280 | 271 |
| COMPLETED | 261 | 255 |
| NOT COMPLETED | 19 | 16 |
Analysis population for the primary outcome, as defined in the registry: Intention-to-treat (ITT)
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.
| Characteristic | Unit | Patients With Ta/T1, Randomized to White Light Cystoscopy | Patients With Ta/T1 Randomized to Hexvix Cystoscopy | Total |
|---|---|---|---|---|
| Participants analysed | 280 | 271 | 551 | |
| Age, Continuous | years | 69.6 (SD 10.68) | 68 (SD 10.79) | 68.8 (SD 10.76) |
| Sex: Female, Male: Female | Participants | 57 | 59 | 116 |
| Sex: Female, Male: Male | Participants | 223 | 212 | 435 |
6. Primary Endpoint
The registry lists the primary outcome as Recurrence Free Survival, measured over up to 4.5 years.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | months |
| Endpoint classification | Time-to-Event Analysis |
Recurrence-free survival is a time-to-event outcome. It concerns the time until recurrence, with the exact event definition and handling of other events not reported in the registry record. The registry specifies a median and a 95% confidence interval for this endpoint in the intention-to-treat (ITT) population, over a timeframe of up to 4.5 years. It does not report the median values or confidence intervals for either group.
General explanation: a median time-to-event estimate marks the point by which half of the relevant population is estimated to have experienced the event, subject to the study’s event definition and analysis. A confidence interval conveys uncertainty around an estimate; it is not a range containing a fixed proportion of individual patients’ event times. Its width depends on the information available and the analysis. When follow-up ends before every participant experiences an event, time-to-event methods can use information from participants who have not yet had the event, provided censoring is handled appropriately. The registry record does not specify its censoring rules or provide enough information to assess their application.
This endpoint is used because recurrence is the outcome the follow-up was intended to examine over time, rather than only at a single assessment. Rate of progression is listed as a secondary outcome, but its definition and results are not reported in the registry record. No conclusion about recurrence or progression can be drawn from an endpoint label alone.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies recurrence-free survival as the primary endpoint and gives its format, population, and timeframe: a median with a 95% confidence interval in the ITT population, followed for up to 4.5 years. It does not report the median estimates, confidence interval limits, event counts, hazard ratios, or a numerical test of the group comparison. Therefore, the registry record does not establish the direction or size of any difference in recurrence-free survival, or how precisely such a difference was estimated.
The study was intended to examine whether improved initial detection and resection with fluorescence cystoscopy/TURB would lead to a longer-term reduction in recurrences compared with white-light cystoscopy/TURB. That statement describes the research question, not a finding. Without the actual endpoint results, it cannot be treated as evidence that recurrence was reduced, increased, or unchanged.
The retrospective, non-interventional design also matters to interpretation. Although the group descriptions refer to assignments in an earlier study, the present follow-up is not described as a randomized comparison; the registry says allocation is not stated and cautions that the arms are not a like-for-like control comparison. Any observed association could therefore reflect differences between groups or features of follow-up, as well as the cystoscopy approach. The record does not provide enough detail to assess these possibilities.
General explanation: a confidence interval helps readers judge the precision of an estimate, while a comparison estimate such as a hazard ratio can describe relative event rates over follow-up under the analysis assumptions. Neither type of estimate, by itself, resolves design limitations or establishes causation. The registry record does not report numerical estimates to interpret in these terms. It lists rate of progression as a secondary outcome but gives no result for it.
Any sample-size figures associated with the posted results are planning illustrations, not evidence of observed power. The registry’s stated assumptions describe an illustration based on the observed effect, rather than the trial’s own design. They do not replace the missing endpoint estimates or show what the follow-up actually found.
9. Statistical Methods Explained
What does a median recurrence-free survival estimate describe?
General explanation: a time-to-event analysis considers both whether an event occurred and when it occurred. A median recurrence-free survival estimate describes the estimated time at which the event experience reaches the median point under the analysis. It is not the average time to recurrence, and it does not say that every patient had an event by that time. The registry identifies the endpoint as a median but does not report its value or the event definition used for the analysis.
Time-to-event methods are often useful when participants have different lengths of observation or when some have not experienced the event by the end of follow-up. Such participants may contribute information up to the time they are last known to be event-free, subject to censoring assumptions. The registry gives a timeframe of up to 4.5 years but does not report the follow-up distribution, censoring rules, or numbers at risk over time. These details are needed to judge how the median was estimated and how much information supported it.
How should a confidence interval be read?
General explanation: a confidence interval expresses statistical uncertainty about an estimate. A narrower interval generally indicates greater precision, while a wider interval indicates greater uncertainty. The interval does not describe the spread of individual recurrence times and should not be read as a guarantee that the true value lies within its displayed limits. Interpretation also depends on the method used to construct it and the assumptions underlying the analysis.
The registry specifies a 95% confidence interval for the primary endpoint, but no interval limits are reported in the registry record. As a result, neither the median’s precision nor the degree of overlap between group estimates can be assessed from the endpoint description alone. An interval for each group would also not be a substitute for a confidence interval for the between-group contrast.
What do hazard ratios contribute?
General explanation: a hazard ratio compares event rates over time between groups under a specified model. It is not a direct comparison of median survival times and does not state the probability that an individual will experience recurrence. Its interpretation depends on the model and assumptions, including whether the relative event rate is reasonably represented by a constant relationship over time.
The registry’s statistical description says that only sponsor-reported hazard ratios are used for time-to-event outcomes. No numerical hazard ratio is included in the registry record. There is therefore no such estimate to interpret. Recalculating a hazard ratio from incomplete summary information would not be appropriate, and no recalculated result is reported.
Why does study design affect statistical interpretation?
General explanation: random assignment can help make comparison groups similar, on average, with respect to factors that affect outcomes. However, a retrospective, non-interventional follow-up does not itself establish that the compared groups were exchangeable during the later observation period. The registry describes historical randomized assignments but states that allocation for this comparison is not reported and warns that the groups are not a like-for-like control comparison. The comparison should therefore be read as descriptive or associative unless further design and analysis information supports stronger interpretation.
The registry does not report adjustment variables, model specifications, or sensitivity analyses. It is not possible to assess whether measured differences between groups were addressed or whether results were robust to alternative analytic choices.
What do the sample-size illustrations mean?
General explanation: a sample-size calculation is a planning tool that describes the amount of information a future study might need under stated assumptions. It is not a measure of how likely the completed study was to detect an effect, and it is not observed power. The registry states that its planning illustration uses the observed effect, a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. For time-to-event outcomes, the stated calculation concerns the total number of events using the Schoenfeld approach; other outcomes are expressed as participants per arm.
These assumptions are not reported as the design plan for this follow-up. The resulting planning illustration cannot establish that the study was adequately designed, nor can it recover a missing treatment-effect estimate. It should be interpreted separately from the observed endpoint results.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four outcome measures and three analyses, but does not describe how the analyses relate to the outcomes, which comparisons were prespecified, or whether any multiplicity adjustment was used. It identifies recurrence-free survival as the primary endpoint and rate of progression as a secondary outcome. The available record does not provide a complete analysis plan, hypothesis hierarchy, or decision rule for interpreting multiple tests.
General explanation: when several outcomes, comparisons, or analysis choices are examined, the chance of at least one apparently notable result can increase. Prespecifying a primary question and controlling or transparently reporting multiplicity can help readers distinguish confirmatory analyses from exploratory ones. Without a stated strategy, a reported p-value or confidence interval would need to be interpreted in the context of the full set of analyses. No numerical p-values or results are reported in the registry record.
The primary population is identified as ITT, but the record does not report how missing observations, loss to follow-up, or participants with incomplete endpoint information were handled. General explanation: an ITT analysis ordinarily retains participants in the groups defined by their original assignment, but it does not by itself specify how missing outcome data are treated. The precise analysis population, exclusions, censoring, and missing-data methods are not reported in the registry record.
Because the follow-up is retrospective and the registry cautions that the groups are not a like-for-like control comparison, these omissions limit assessment of the reliability and comparability of the estimates. The record also does not report interim analyses or a sample-size justification for the follow-up; neither should be inferred from the planning illustration.
11. What the Result Does, and Does Not, Mean
The record establishes the study’s purpose and the form of its primary endpoint, but it does not report the endpoint estimates needed to describe the observed recurrence-free survival. The median values and 95% confidence intervals are not reported in the registry record. Numerical results for the secondary outcome, rate of progression, are also not reported. Accordingly, the study description alone does not show whether recurrence differed between the groups or whether any difference was precise.
The intended question was whether initial fluorescence cystoscopy/TURB might be followed by a longer-term reduction in recurrence compared with white-light cystoscopy/TURB. An intention stated in a study description is not a result. No claim that either approach reduced recurrence, increased recurrence, or had no difference is supported by the results available in the registry record.
The distinction between association and causation is important. This was a retrospective, non-interventional follow-up, and the registry explicitly cautions that the arms are not a like-for-like control comparison. Historical randomized group labels do not, on their own, demonstrate that the later follow-up comparison retained the protections of a randomized trial. The allocation process for this comparison is not reported in the registry record.
General explanation: statistical uncertainty and study design answer different questions. Confidence intervals can communicate uncertainty around an estimate, but they cannot remove bias arising from unequal follow-up, outcome ascertainment, or differences between groups. The registry record does not provide enough information to assess these issues, and it does not provide the numerical estimates needed to assess precision.
The registry lists adverse-event group entries with zero counts for the reported serious and other categories, while deaths are recorded as null. These entries should not be taken as proof that no adverse events or deaths occurred; the record does not explain the completeness or meaning of these fields. The findings described in the registry should therefore be read as limited by absent outcome results and incomplete analytic detail, not as a basis for clinical decisions.
12. Why This Trial Matters Statistically
This study raises a statistically important distinction between an intervention’s immediate detection performance and outcomes observed over longer follow-up. The stated rationale is that improved initial detection and resection might lead to a longer-term difference in recurrence. Testing that question requires outcome information over time, together with clear definitions of recurrence, follow-up, censoring, and the comparison being made. The registry identifies recurrence-free survival as the primary endpoint but does not report its numerical results or key analysis details.
The study also illustrates why a historical randomized assignment and a later retrospective comparison should not automatically be treated as equivalent. The registry describes the groups by their prior assignments, yet characterizes this follow-up as non-interventional and warns that the arms are not a like-for-like control comparison. Statistical interpretation must take account of how a comparison was formed, not just the labels attached to its groups.
General explanation: an estimate can be statistically precise and still be affected by bias; conversely, an unbiased estimate can remain uncertain when information is limited. A sound interpretation therefore considers the estimate, its uncertainty, the design, and the completeness of reporting together. In this record, the endpoint format and timeframe are stated, but the estimates and analysis details needed for that assessment are not reported.
The record also distinguishes planning assumptions from observed evidence. A sample-size illustration based on an observed effect is not the trial’s own design justification and is not observed power. This distinction matters because planning calculations describe hypothetical requirements under assumptions; they do not establish the strength of evidence in a completed follow-up. The registry does not provide a sample-size justification for the study.
13. 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 primary limitation for statistical interpretation is that the registry record does not report the primary endpoint estimates. Although recurrence-free survival is specified as a median with a 95% confidence interval, neither the median nor the interval limits are reported. Event counts, group-specific analysis sizes, and a numerical between-group comparison are also not reported. The posted record therefore does not support an assessment of effect direction, magnitude, or precision.
The record describes a retrospective, non-interventional follow-up and cautions that the groups are not a like-for-like control comparison. It does not state the allocation method for this follow-up comparison. The groups’ historical randomized labels do not resolve this limitation without details about how patients were selected and followed in the retrospective study.
Important analytic details are absent: the recurrence definition, outcome ascertainment procedures, follow-up distribution, censoring rules, missing-data handling, model specification, adjustment strategy, and sensitivity analyses are not reported in the registry record. Multiplicity procedures and the relation between the listed analyses and outcomes are also not described. These omissions prevent a full evaluation of internal validity and robustness.
The registry lists rate of progression as a secondary outcome but does not report its definition or numerical result. Adverse-event entries show zero counts in the displayed categories and null death values, but the record does not explain how those entries were collected or whether they represent complete follow-up. They cannot establish absence of adverse events or deaths.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Longer-term Recurrence Rates in Patients With Bladder Cancer After Hexvix (Cysview)Fluorescence Cystoscopy/TURB — NCT01166230.
- Registry record last updated 2019-04-09; status last verified 2019-03.
- Results first posted 2013-11-14.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
17. Record Summary
NCT01166230 is a completed, open, non-interventional, retrospective, comparative, multicenter follow-up study sponsored by Photocure. It concerns patients with Ta/T1 bladder cancer who were included in the previously completed study PCB305/04 and compares longer-term recurrence after Hexvix (Cysview) fluorescence cystoscopy/TURB or white-light cystoscopy/TURB. The registry reports enrollment of 551, a start in 2010-06, and primary completion in 2010-12.
The primary endpoint is recurrence-free survival in the ITT population, reported as a median with a 95% confidence interval over up to 4.5 years. Rate of progression is listed as a secondary outcome. The numerical endpoint results, analysis details, and missing-data methods are not reported in the registry record. The registry cautions that the arms are not a like-for-like control comparison.