2 Phase Comparison of Pre-operative CT and PET Images for Metastatic Colorectal Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for 2 Phase Comparison of Pre-operative CT and PET Images for Metastatic Colorectal Cancer (NCT01821105), a na phase 2 study. The primary outcome is Detection of Position Accuracy With Handheld Probe on Anatomical Location..

2. Clinical Question

3. Trial Design

This is a phase II, completed, single-group study sponsored by Ohio State University Comprehensive Cancer Center. The registry lists enrollment of 21 and no allocation to randomized arms. Masking is listed as none. The study start is recorded as 2004-03 and primary completion as 2009-11. These registry entries describe the study structure and timeline; they do not establish how participants were selected or how the investigators conducted every study procedure.

The registered group is described as receiving preoperative whole-body PET and CT scans, followed by fluoro-deoxyglucose intravenously 60-90 minutes before surgery. During surgery, participants underwent CT procedures involving a handheld probe and computer navigation system. The title and brief summary frame the work as a pilot phase II evaluation of imaging and detection in patients undergoing surgery for metastatic colorectal cancer. The record does not report the sequence or detailed operating procedures for each imaging modality beyond the description above.

This design is not a randomized comparison. The registry lists one group, and its allocation entry is not applicable. As a result, a contrast between randomized treatment arms cannot be interpreted from the registered design. The title refers to comparison of preoperative CT and PET images and intraoperative detection, but the primary outcome description focuses on the number of tumor lesions detected by the probe. The registry does not provide outcome estimates that compare the methods.

The primary completion date and completed status indicate that the study is registered as completed. They do not, by themselves, show that outcome data were fully recorded or analyzed. The record lists three outcome measures and zero analyses. It identifies tumor detection and adverse events and complications among the secondary outcomes, but does not supply their detailed results or analysis methods. Information about eligibility criteria, participant flow, protocol deviations, or reasons for any missing data is 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

Analysis population for the primary outcome, as defined in the registry: number of tumor lesions detected by the probe

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 Detection of Position Accuracy With Handheld Probe on Anatomical Location., measured over up to 12 months.

The primary endpoint is titled “Detection of Position Accuracy With Handheld Probe on Anatomical Location.” The unit is lesions, and the population description says it is the number of tumor lesions detected by the probe. In practical terms, this defines a count of lesions detected during the surgical setting described in the study record. It is intended to address whether the probe detects tumor lesions at anatomical locations.

Lesion detection is relevant to the study’s stated focus because the brief summary concerns the use of preoperative and intraoperative imaging to find colorectal cancer and guide surgery. However, the endpoint description does not fully specify what qualifies as a detected lesion, how the anatomical location is confirmed, or what degree of positional accuracy counts as accurate. The title uses the language of position accuracy, while the stated population measure is a number of lesions detected. The registry record does not resolve how those concepts are operationalized or whether accuracy is assessed separately from detection.

The timeframe is up to 12 months. The record does not explain whether this refers to the period for measuring lesion detection, follow-up, or another aspect of outcome collection. No primary-endpoint count, estimate of accuracy, uncertainty interval, or analysis is reported in the registry record. Without those results and a detailed endpoint definition, the endpoint’s intended measurement can be described, but its observed performance cannot be assessed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins with identifying what was measured and how the study was structured. In this study, the primary outcome is described as the number of tumor lesions detected by a handheld probe, with lesions as the unit. The registered design is single group, with no allocation to randomized arms and no masking. This means the registry record does not describe a randomized arm-to-arm estimate. The title refers to comparisons among imaging approaches, but a title alone does not establish a statistical comparison or provide its result.

What does a lesion count measure?

A count records how many events or objects meet a defined criterion. For a lesion-detection outcome, interpretation depends on the rule for deciding that a lesion was detected and on how the reference location or diagnosis is established. General statistical point: a count does not automatically measure sensitivity, specificity, or positional accuracy. Those quantities require a defined reference standard and a clear accounting of detected and undetected lesions. The registry record does not report those definitions, the number of lesions available for detection, or a contingency table of probe findings against a reference method.

The endpoint title includes “Position Accuracy,” while the outcome description identifies the number of tumor lesions detected by the probe. These descriptions may relate to different aspects of detection: whether a lesion is found and whether its location is identified accurately. The record does not specify an accuracy tolerance, the method for verifying anatomical location, or whether lesion detection and location accuracy were analyzed as separate outcomes. Without these details, the endpoint’s intended clinical meaning is understandable at a broad level, but the precise statistical quantity is not fully defined.

Why does the design matter?

A single-group study can describe observations made in its registered group, but it does not create a randomized control comparison. The design therefore does not protect a between-group contrast from differences created by allocation, because no randomized allocation is registered. General statistical point: comparative claims require a defined contrast and a method for estimating it. The record does not report a comparator group’s results, a paired comparison of imaging methods, or an estimate that quantifies agreement or difference between them. It is not possible to infer such estimates from the study title.

Masking is listed as none. Masking can reduce the influence of knowledge about a participant’s other test results or group assignment on assessment, where such knowledge could affect measurement. That is a general methodological consideration, not evidence that assessment bias occurred in this study. The record does not explain whether probe operators or outcome assessors had access to preoperative imaging findings, nor does it report procedures used to standardize lesion assessment.

How should uncertainty be understood?

General statistical point: an estimate describes the observed data, while a confidence interval describes a range of values compatible with the data under the assumptions of the analysis. A narrow interval generally indicates greater statistical precision than a wide interval, but precision is not the same as freedom from bias or clinical importance. No primary estimate or confidence interval is reported in the registry record, so the precision of lesion detection cannot be assessed. No p-value or model-based result is reported either.

The record lists zero analyses. It does not identify a statistical model for the primary outcome, an adjustment strategy, or a prespecified hypothesis test. Count outcomes can sometimes be analyzed using count-data methods. General statistical point: if the observed variability in counts is greater than a simple model expects, over-dispersion may make standard errors too small under that model; methods allowing greater variability may then be appropriate. This is a general consideration only. The registry record does not report the distribution of lesion counts or an analysis that would allow assessment of over-dispersion.

What do the planning assumptions mean?

A planning illustration is described as using 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 fraction of the observed effect. It is explicitly a planning illustration rather than the trial’s own design. The registered study is single group, so the hypothetical equal-allocation assumption should not be mistaken for the study’s enrollment plan or a description of actual trial arms. The record does not report a sample-size justification for the study or an observed-effect estimate that can be interpreted as a trial result.

General statistical point: a planning calculation estimates the sample size that might be needed under specified assumptions. It is conditional on the chosen effect, variability, significance level, and design. It does not demonstrate that the study had a particular probability of detecting an effect after data collection. Such a calculation is not observed power, and it cannot replace a reported estimate with its uncertainty. No sample-size justification or analysis plan is reported in the registry record.

For this study, the most important methodological conclusion is that the registry describes the clinical setting and endpoint concept but does not provide the data or analysis needed to quantify detection performance. The number enrolled, the study’s completion status, and the safety counts do not supply a substitute for the missing primary outcome estimate.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures, including the primary lesion-detection outcome and secondary outcomes concerning all adverse events and complications and tumor detection. It reports zero analyses. No statistical analysis plan, hierarchy of secondary outcomes, adjustment for multiple testing, or explanation of how the outcomes relate to one another is reported in the registry record.

General statistical point: when several outcomes or hypotheses are tested, the chance of at least one apparently unusual result can increase unless the analysis plan accounts for multiplicity. Whether adjustment is needed depends on the scientific questions and the intended interpretation. Because no outcome analyses or testing strategy are reported, the record does not permit an assessment of how multiplicity was handled. It would be inappropriate to assume either that adjustment was performed or that it was unnecessary.

The record does not report missing-data counts, reasons for missingness, participant flow after enrollment, or analysis populations such as intention-to-treat or evaluable participants. It also does not state how incomplete lesion assessments or unavailable imaging results were handled. These omissions matter because missing outcome information can affect both the estimated detection count and the precision of an estimate. General statistical point: the impact of missing data depends partly on why observations are missing and on the assumptions used to handle them; no such assumptions are reported.

Enrollment was 21, but the registry does not establish that all enrolled participants contributed evaluable primary-outcome data. The safety denominators are recorded as 21 for each listed category, but they do not define the analysis population for the lesion endpoint. No imputation, exclusion rules, or sensitivity analyses are reported in the registry record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry records zero serious adverse events among 21 participants at risk and zero other adverse events among 21 participants at risk. These are counts in the registered safety categories. The secondary outcomes include all adverse events and complications, but the record provides no event terms, grades, timing, or participant-level breakdown. Deaths are not reported in the registry record.

These zero counts should be read narrowly: no events are recorded in those categories in the registry entry. They do not establish that no events occurred outside the recorded categories, that surveillance was complete, or that the risk of an event is zero. The record does not report how adverse events were defined, how long safety was assessed for each participant, or how missing safety information was handled.

The at-risk counts indicate the denominators used for the listed safety entries; they do not provide detail about exposure or follow-up. Without event descriptions and collection procedures, the counts cannot support a detailed comparison of safety or a broad conclusion about safety. The study has a single registered group, so the registry record also contains no separate randomized safety comparator.

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

The registry record establishes that this was a completed phase II, single-group study with enrollment of 21. It describes preoperative PET and CT imaging and intraoperative procedures involving a handheld probe and computer navigation. Its primary outcome concerns the number of tumor lesions detected by the probe, with a timeframe of up to 12 months. These registry entries explain the study’s topic and the intended measurement.

The record does not report a primary-endpoint result. It therefore does not show how many lesions were detected, how accurately their locations were identified, or how the detection methods compared. No confidence interval or other estimate of uncertainty is reported. The record also lists zero analyses. The title’s use of “comparison” cannot be taken as evidence of a quantified comparison or a result favoring any method.

The zero recorded serious and other adverse-event counts are limited to the registry’s entries and denominators. They do not establish an absence of risk, and the safety details needed for a fuller interpretation are not reported in the registry record. Nor do the safety counts address the primary detection question.

General statistical point: conclusions about a measured effect depend on having a clearly defined outcome, an appropriate analysis, and a reported estimate with information about its uncertainty. Here, the endpoint is described only partly, and its analysis is absent. Thus, the posted information cannot establish the magnitude, precision, or comparative performance of lesion detection. It also cannot support conclusions about whether an imaging or intraoperative approach changes surgical outcomes. Those questions require results and analyses not reported in the registry record.

The appropriate reading is descriptive rather than evaluative: the registry documents the study’s registered design, procedures, endpoint concept, enrollment, and safety counts, while leaving the primary outcome unanswered. No treatment recommendation or claim of effectiveness follows from these entries.

13. Why This Trial Matters Statistically

This study raises a useful statistical distinction between a clinically important question and a statistically interpretable endpoint. Detecting a tumor lesion during surgery is the clinical focus, while the registered primary measure is the number of lesions detected by a handheld probe. To interpret that count as evidence about detection accuracy, readers would also need a clear definition of a lesion, a reference method for confirming its presence and location, and a description of how findings were compared. Those details are not reported in the registry record.

The registered design also matters. The study is single group, with no randomized allocation or separate control group. The title frames the work as a comparison of CT and PET images and intraoperative detection, but statistical comparison requires reported data and an estimand that specifies what is being contrasted. The record provides neither comparative estimates nor an analysis. This illustrates why a study’s title and aim cannot substitute for a defined analysis and reported results.

There is also a useful lesson in separating study completion from evidence of an outcome. A completed status and enrollment of 21 describe conduct and registration, not the size or reliability of a detection effect. The absence of a primary result prevents assessment of both its magnitude and its precision. Likewise, the recorded zero safety counts are descriptive entries, not proof of zero risk.

For biostatisticians and clinical researchers, the record highlights the importance of prespecifying operational endpoint definitions, analysis populations, missing-data handling, and the intended comparison. Without those elements in the registry, readers cannot determine whether the endpoint measures lesion detection, anatomical localization, or both, or how uncertainty should be interpreted. The statistical value of the record lies in making these gaps visible rather than implying a result that it does not report.

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 registry record does not report a primary-outcome result, an estimate of detection accuracy, or an uncertainty interval. It lists zero analyses, so no statistical model, hypothesis test, or adjustment strategy can be assessed. The primary endpoint’s title refers to position accuracy, while its description defines the population measure as the number of tumor lesions detected by the probe. The record does not explain how accuracy was operationalized or how anatomical location was verified.

The design is single group, with no randomized comparator. Although the study title describes comparisons, the record does not provide a comparative estimate or clarify whether the methods were compared using paired lesion-level data, another reference standard, or another approach. Masking is listed as none, but the record does not state who assessed the endpoint or whether assessors knew imaging findings. These details limit interpretation of potential measurement bias, without establishing that bias occurred.

The registry does not report participant-level condition distribution, detailed eligibility criteria, participant flow, the number of evaluable lesions, or the analysis population for the primary endpoint. It also does not report missing-data counts, missingness reasons, or sensitivity analyses. The timeframe is listed as up to 12 months, but its relation to endpoint assessment is not explained. Safety reporting is limited to aggregate counts; event definitions, severity, timing, and deaths are not reported in the registry record.

Finally, the planning description is not the trial’s design or sample-size justification. The registry record does not report the rationale for enrollment or a protocol-based power calculation. These limits mean that the posted information can describe the study’s registered structure and recorded safety counts, but cannot establish the performance or comparative value of the detection methods.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: 2 Phase Comparison of Pre-operative CT and PET Images for Metastatic Colorectal Cancer — NCT01821105.
• Registry record last updated 2016-03-02; status last verified 2016-02.
• Results first posted 2016-02-03.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry identifies NCT01821105 as a completed phase II study sponsored by Ohio State University Comprehensive Cancer Center. It lists enrollment of 21, a single-group model, no masking, and allocation as not applicable. The study start is recorded as 2004-03 and primary completion as 2009-11.

The registered procedures include preoperative PET and CT, fluoro-deoxyglucose before surgery, and intraoperative CT involving a handheld probe and computer navigation. The primary outcome concerns the number of tumor lesions detected by the probe, with a timeframe of up to 12 months. Secondary outcomes include all adverse events and complications and tumor detection.

The registry reports zero serious adverse events and zero other adverse events among 21 at risk in each category. It reports zero analyses and does not report a primary-outcome result, comparative estimate, or uncertainty interval. The record therefore describes the study and its registered measurements but does not establish detection accuracy or comparative performance.