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 Ploidy and Stroma in Early Rectal Cancer (NCT03039595), a registered phase not stated study. The primary outcome is Correlation Between Ploidy Status With Local Recurrence of Cancer.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03039595 |
| Phase | Phase not stated |
| Condition | Rectal Cancer |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 150 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Oxford University Hospitals NHS Trust |
| Results posted | Yes |
2. Clinical Question
Population
People with early rectal cancer who underwent surgery to remove the tumour. The primary outcome description concerns participants with available ploidy status and follow-up information after surgery. The registry record says ploidy assessment failed in 3 patients for technical reasons.
Intervention
This is an observational study, not a treatment comparison. The study measured ploidy and tumour:stroma ratio in tumour tissue to investigate whether these pathological features were associated with later outcomes.
Comparator
No randomized comparator is described. The intended comparisons are between categories of ploidy status, and between levels or categories of tumour:stroma ratio. The registry record does not state how those categories were defined or how participants were grouped.
Primary question
Is ploidy status associated with local recurrence of rectal cancer during follow-up after surgery? The primary outcome description specifies follow-up between 6 months and 9 years after surgery, with a minimum of 6 months. The study also lists questions about the association of ploidy status and tumour:stroma ratio with overall survival.
The scientific motivation is prognostic: standard pathological assessment can help characterize how advanced a tumour is, while uncertainty remains about predicting recurrence. The study asks whether additional tissue measurements could be associated with outcomes and thereby provide further prognostic information. An association would not by itself show that either tissue feature causes recurrence or survival differences. Nor does the registry record establish that the measurements improve prediction beyond standard pathological information. Those questions require results and analyses that are not reported in the registry record.
3. Trial Design
The registry record describes an observational study titled “Ploidy and Stroma in Early Rectal Cancer,” sponsored by Oxford University Hospitals NHS Trust. Its stated purpose was to correlate ploidy and stroma analysis with prognosis in early rectal cancer. The study status is COMPLETED. The recorded enrollment is 150. The recorded start date is 2017-03-29, and the primary completion date is 2019-05-31.
The intervention entry is “Ploidy and tumour:stromal ratio measurements,” classified as OTHER. In this context, that entry describes measurements rather than an assigned treatment. The record does not describe random allocation, and allocation is not stated. It therefore does not define treatment and control arms as a randomized trial would. Any comparisons are observational comparisons based on measured tumour characteristics, and participants may differ in other ways that are related to outcomes.
The primary outcome concerns the correlation between ploidy status and local recurrence. The listed secondary outcomes concern ploidy status and overall survival, and tumour:stroma ratio and overall survival. The primary outcome description refers to follow-up information between 6 months and 9 years after surgery, with a minimum of 6 months. The record does not describe the follow-up schedule, methods for measuring recurrence, or the statistical method used to assess correlation.
Although the study is marked completed, completion status does not supply the missing outcome estimates. The registry record reports no analyses. It also does not state the protocol’s sample-size justification, a planned statistical analysis, interim analyses, or how the observational comparisons were to be adjusted for other prognostic factors.
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 |
|---|---|
| STARTED | 150 |
| COMPLETED | 143 |
| NOT COMPLETED | 7 |
Analysis population for the primary outcome, as defined in the registry: Only patients for whom ploidy status was available were included in the analysis (ploidy assessment failed in 3 patients for technical reasons)
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 |
|---|---|---|
| Participants analysed | 143 | |
| Age, Continuous | years | 69 (38 to 94) |
| Sex: Female, Male: Female | Participants | 56 |
| Sex: Female, Male: Male | Participants | 87 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: United Kingdom | participants | 143 |
| Tumour stage: pT1 (tumour confined to the inner layer of the bowel) | Participants | 76 |
| Tumour stage: pT2 (tumour extends into the muscle layer of the bowel wall) | Participants | 58 |
| Tumour stage: pT3 (tumour has reached the outer lining of the bowel wall) | Participants | 9 |
| Post-TEM management: Surveillance | Participants | 88 |
| Post-TEM management: Completion radical surgery | Participants | 13 |
| Post-TEM management: Adjuvant radiotherapy | Participants | 42 |
6. Primary Endpoint
The registry lists the primary outcome as Correlation Between Ploidy Status With Local Recurrence of Cancer, measured over a minimum of 6 months after surgery.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the correlation between ploidy status and local recurrence of rectal cancer. The registry describes the measure as a count of participants and says results of ploidy status would be correlated with patient follow-up information after surgery. The stated timeframe is a minimum of 6 months after surgery; the description gives a follow-up span between 6 months and 9 years.
This endpoint addresses a prognostic question: whether a measured tumour feature is associated with a later recurrence outcome. In general, recurrence is clinically relevant because it describes cancer returning locally after surgery. An association between a tissue feature and recurrence could help characterize prognosis, but association alone does not establish that the feature causes recurrence or that measuring it improves predictions beyond existing information.
The record does not report the number of participants who experienced local recurrence, the distribution of recurrence across ploidy categories, or an estimate of the association. It also does not describe the operational definition of local recurrence, how recurrence status was verified, or how differing lengths of follow-up were handled. Consequently, the endpoint’s intended meaning is clear at a broad level, but its observed result and precision are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study’s question and design, but it does not provide outcome analyses. It reports no analyses, and no primary outcome counts, association estimates, confidence intervals, or p-values are reported in the registry record. Therefore, the strength, direction, and precision of any association between ploidy status and local recurrence cannot be determined from the posted results. The same limitation applies to the listed associations with overall survival and tumour:stroma ratio.
In general, a correlation or association describes how two measured characteristics vary together. It does not establish that one characteristic causes the other. In an observational study, a relationship may also reflect other differences among participants, such as differences in tumour characteristics or clinical care. The registry record does not state whether adjusted analyses were planned or performed, so it is not possible to assess whether potential confounding was addressed.
Precision is also unavailable. In general, a confidence interval describes a range of estimates compatible with the observed data under the statistical method used; a narrow interval indicates greater precision than a wide interval. No confidence interval is reported for the primary association, and the record does not describe the method used to calculate one. The number enrolled does not, by itself, reveal the precision of an outcome estimate. Precision depends on the number with usable measurements and outcomes, the event distribution, follow-up, and the analysis method.
The record states that ploidy assessment failed in 3 patients for technical reasons and that only participants for whom ploidy status was available were included in the primary analysis. It does not report how many participants had an observed recurrence outcome or how many were included in a completed analysis. It also does not explain how participants without adequate follow-up were handled. These omissions make it impossible to judge how representative an analyzed group would be of the enrolled group.
The serious adverse event figures report 0 affected participants in each of the serious and other adverse event categories, with 143 at risk in each category; the death count is 27. These are descriptive counts in the registry record. No causal interpretation of the deaths is established by those figures, and the record does not provide an analysis relating deaths to ploidy, stroma ratio, or the study measurements.
Overall, the posted information supports a description of the research question and outcome framework, not a conclusion about whether either measurement was associated with prognosis. The results needed to make that assessment are not reported in the registry record.
9. Statistical Methods Explained
The study’s central statistical task is an observational association analysis. Participants were not assigned to ploidy or stroma categories as treatments; the categories arise from measurements of tumour tissue. In general, observational analyses compare outcomes across measured groups or quantify how outcomes vary with a measured feature. Such analyses can identify patterns, but they cannot by themselves establish causality. A causal interpretation would require additional assumptions and careful consideration of other factors associated with both the tissue measurement and the outcome.
What does a participant count represent?
The primary outcome is described as a count of participants, and the registry classifies the outcome as binary. In general, a binary outcome records whether each participant did or did not experience an event, such as local recurrence. Counts are useful for describing how many events occurred, but they do not alone describe the association between the event and ploidy status. That requires the counts in the relevant ploidy groups, a comparison or association estimate, and an account of uncertainty. The registry record does not report those results.
The record does not state the exact ploidy categories, how the tumour:stroma ratio was represented in analysis, or what statistical test or model was used. These details matter because different methods answer different questions. For example, a comparison of event proportions treats follow-up differently from a time-to-event analysis. A model using a continuous measurement can also differ from an analysis that divides the measurement into categories. These are general distinctions; the registry record does not say which approach was used.
Why does follow-up matter?
The primary outcome description gives a follow-up span between 6 months and 9 years after surgery, with a minimum of 6 months. In general, participants followed for different lengths of time have different opportunities for an event to be observed. A simple event count may not fully represent that difference. Time-to-event methods can account for the timing of events and for participants whose event status is not observed through the end of follow-up, using censoring assumptions. The registry record does not report whether such methods were used, how censoring was defined, or whether follow-up was complete enough for the intended analysis.
The secondary outcomes name overall survival in relation to ploidy status and tumour:stroma ratio. Overall survival is a time-to-event outcome in general, but the record does not specify the analysis method, the event definition used in the analysis, or the estimate for either secondary outcome. No survival curves, hazard estimates, or other results are reported in the registry record, so none can be interpreted from the available information.
How should precision and planning be understood?
In general, an effect estimate describes the size and direction of an association, while a confidence interval communicates its statistical uncertainty. A p-value, when used, measures how compatible the data are with a specified null hypothesis under a statistical model; it does not measure the size or clinical importance of an association. The registry record does not report an estimate, confidence interval, p-value, or the method used to obtain them. Therefore, no claim about statistical significance or precision can be made.
Planning illustrations based on an observed effect are not observed power and are not evidence that the study was designed around that effect. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a stated fraction of the observed effect. The assumptions describe a planning calculation, not an allocation scheme for this observational study. They do not establish that the study had two randomized arms, and they do not replace a protocol-based sample-size justification. The registry record does not report that justification or the effect estimate on which an illustration would depend.
In general, over-dispersion occurs when outcome variation exceeds what a statistical model assumes. If present, it can make standard errors too small and confidence intervals too narrow unless the model accounts for it. This is a general methodological consideration; the registry record does not report an over-dispersion assessment or identify a count model for the primary outcome. Likewise, it does not describe model diagnostics, covariate selection, missing-data procedures, or sensitivity analyses. These omissions mean that the adequacy of any statistical model cannot be evaluated from the record.
Finally, the registry reports no analysis records. That should be read as an absence of posted analyses in the registry, not proof that no analyses were performed elsewhere. Without analysis methods and results, readers cannot verify whether the questions named in the record were answered as planned, whether the data supported the assumptions of a chosen method, or whether findings were robust to alternative analytic choices.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists a primary outcome concerning ploidy status and local recurrence, along with secondary outcomes concerning ploidy status and overall survival and tumour:stroma ratio and overall survival. It does not report a multiplicity plan. In general, when several outcomes or comparisons are examined, the chance of at least one apparently notable result can increase. A prespecified hierarchy, adjustment procedure, or clear distinction between confirmatory and exploratory analyses can help readers interpret multiple tests. None of those procedures is described in the registry record, so it is not possible to determine how multiple outcomes were handled.
The record reports no analyses. It therefore provides no outcome-specific analysis populations, estimates, uncertainty intervals, or missing-data summaries. For the primary analysis, the population is described as participants for whom ploidy status was available; the record says ploidy assessment failed in 3 patients for technical reasons. It does not state how unavailable measurements were handled in the secondary outcomes, whether other data were missing, or how many participants had complete follow-up information.
In general, missing-data methods depend on why information is absent and on what information remains available. Excluding participants with unavailable measurements can affect an association if measurement failure is related to participant or tumour characteristics. Imputation or other methods also require assumptions and should be described. The registry record does not report imputation, sensitivity analyses, or assumptions about missingness. It also does not specify how participants with incomplete follow-up or unknown recurrence status were treated.
These gaps prevent assessment of whether the analyzed populations match the intended study population or whether missing information could influence the findings. They also prevent distinguishing an analysis based on all eligible participants from one based on a smaller subset.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Patients | 0 | 143 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Patients | 27 of 143 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Patients | 0 of 143 |
The registry record lists 143 participants at risk in the serious adverse event category and 0 affected. It also lists 143 at risk in the other adverse event category and 0 affected. The recorded death count is 27, and no top serious adverse event terms are listed.
These figures should be read as descriptive registry counts, not as evidence about whether the tissue measurements caused or prevented an adverse event. This was an observational study of ploidy and tumour:stroma ratio measurements, not a randomized comparison of treatments. The record does not explain the relationship between the death count and adverse event reporting, provide causes of death, or link deaths to recurrence or the measured tumour features. The meaning of the at-risk denominators and the period over which adverse events were collected are not further described in the registry record.
A count of 0 affected participants in an adverse event category does not, by itself, establish that no events could occur or that the measurements are safe. It describes what the registry reports for that category. Without event definitions, collection details, and a comparator suited to the question, these counts cannot support a causal safety comparison.
12. What the Result Does, and Does Not, Mean
The study addresses a relevant prognostic question: whether ploidy status or tumour:stroma ratio is associated with local recurrence or overall survival in early rectal cancer. Its observational design is suitable for investigating patterns in measured tumour characteristics, but associations from such a design do not automatically show that a characteristic causes an outcome or improves prediction.
The registry record does not report the analyses or outcome results. It therefore does not show whether ploidy status was associated with local recurrence, whether either measurement was associated with overall survival, or how large or precise any association might have been. No conclusion about the direction or strength of these relationships can be drawn from the study description alone. The record also does not establish whether the measurements add prognostic information beyond standard pathological assessment.
Even if an association were reported, its interpretation would depend on the definition of the measurement groups, the outcome ascertainment, the length and completeness of follow-up, and the statistical methods used. Other participant or tumour characteristics could influence both a tissue measurement and an outcome. The record does not describe adjusted analyses, so it cannot show whether such potential confounding was addressed.
The study’s completion status and enrollment describe the conduct recorded in the registry, not the success of an analysis or the certainty of a result. The primary population is described as participants with available ploidy status, and technical assessment failed in 3 patients. The record does not state the final analysis population or how missing measurements and follow-up were handled.
The appropriate reading is therefore limited: this was a completed observational study designed to examine potential prognostic associations, but its results are not reported in the registry record. The posted information does not establish whether the measured features predict recurrence or survival, nor whether they should influence clinical decisions.
13. Why This Trial Matters Statistically
This study raises an important statistical distinction between prognosis and treatment effect. A prognostic feature is associated with the likelihood or timing of an outcome, whereas a treatment effect concerns the difference caused by assigning one intervention rather than another. The study record describes tissue measurements and outcomes, not randomized treatment assignment. Its intended question is therefore prognostic, and an observed association would need to be interpreted as such.
The design also highlights why association estimates require more than an enrollment figure. The number of participants with usable measurements, the number with observed outcomes, follow-up duration, and event distribution all influence the information available for an analysis. The record notes technical failures in ploidy assessment but does not report the final analysis population or outcome counts. Without those details and an estimate with uncertainty, readers cannot judge how informative the data were.
Another statistical issue is whether a new marker adds information beyond existing assessments. A marker can be associated with an outcome without improving prediction. In general, assessing additional prognostic value requires comparing predictions that include and exclude the marker and evaluating how well those predictions perform. The registry record does not report such an analysis, so it does not establish incremental predictive value.
Finally, the study’s stated motivation reflects the challenge of translating pathology measurements into useful prognostic information. A clear analysis plan, transparent handling of missing measurements and follow-up, and complete reporting of estimates and uncertainty are essential for judging whether a proposed marker merits further evaluation. Because those analysis results are not reported in the registry record, the statistical contribution that can be assessed is the question and design rather than a demonstrated prognostic finding.
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.
The main limitation for interpretation is the absence of posted outcome analyses. The registry record reports no analyses and does not provide primary or secondary outcome estimates. Readers therefore cannot assess the direction, magnitude, or precision of the proposed associations.
The study is observational, and allocation is not stated. There is no like-for-like randomized control comparison. Differences in measured outcomes across ploidy or stroma categories could reflect other differences among participants rather than the tissue features themselves. The record does not describe adjustment for confounding or identify the covariates that might have been considered.
The primary analysis population is restricted to participants with available ploidy status; the record states that assessment failed in 3 patients for technical reasons. It does not report the final number analyzed, the number with local recurrence, the distribution of events across ploidy categories, or how missing follow-up was treated. The consequences of technical failure or incomplete outcome information therefore cannot be assessed.
Follow-up is described as occurring between 6 months and 9 years after surgery, with a minimum of 6 months. The record does not explain how differences in follow-up duration were handled, how recurrence was defined or confirmed, or whether participants were censored in an analysis. Those details are especially relevant when outcomes can occur at different times.
The registry does not report measurement thresholds, analysis methods, multiplicity handling, interim analyses, sensitivity analyses, or a sample-size justification. It also does not report whether the measurements improved prediction beyond standard pathological assessment. These missing details limit both reproducibility and the assessment of clinical meaning, even though the study status is COMPLETED.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Ploidy and Stroma in Early Rectal Cancer — NCT03039595.
- Registry record last updated 2022-06-09; status last verified 2022-03.
- Results first posted 2022-06-09.
- 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.
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18. Record Summary
The registry record describes a completed observational study of ploidy and tumour:stroma ratio measurements in early rectal cancer, sponsored by Oxford University Hospitals NHS Trust. Enrollment is recorded as 150. The study began on 2017-03-29, with primary completion on 2019-05-31.
The primary question concerns the association between ploidy status and local recurrence after surgery. Listed secondary questions concern ploidy status and overall survival, and tumour:stroma ratio and overall survival. The primary outcome description gives follow-up between 6 months and 9 years after surgery, with a minimum of 6 months.
The record reports that ploidy assessment failed in 3 patients for technical reasons and that only participants with available ploidy status were included in the primary analysis. It reports no analyses or outcome estimates. The registry record therefore documents the study’s purpose and design, but not whether the planned prognostic associations were observed.