Assessment of Diagnostic Accuracy and Performance of Digital Breast Tomosynthesis Compared to Mammography: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Assessment of Diagnostic Accuracy and Performance of Digital Breast Tomosynthesis Compared to Mammography (NCT02306265), a na na study. The primary outcome is Number of Participants With Imaging Data Collected.

2. Clinical Question

3. Trial Design

The registry describes the ADAPT-SCR recruitment plan as an effort to collect images and other data from asymptomatic women undergoing screening mammography. Each participant is described as undergoing 2D imaging with full-field digital mammography (FFDM) and 3D imaging with digital breast tomosynthesis (DBT). These are two imaging methods within a single-group study model, not separate randomized groups. Allocation is listed as NA, and masking is listed as none.

The listed enrollment is 250. The record gives a study start of 2015-05 and a primary completion date of 2017-07-07, with status completed. These registry entries describe the study record; they do not establish how many participants ultimately had usable images or completed every procedure. The primary endpoint's timeframe is within 30 days of enrollment.

GE Healthcare is listed as the sponsor. Phase is listed as NA. The record lists 3 outcome measures, while the primary measure described in detail is the number of participants with imaging data collected. It lists 0 analyses. A diagnostic-accuracy comparison would ordinarily require reported outcomes and a defined analysis, but those results and methods are not reported in the registry record. The record therefore supports a description of the planned imaging-data collection and study structure, not a conclusion about comparative diagnostic performance.

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: The efficacy population for primary outcome were subjects meeting study inclusion/exclusion criteria with no protocol violations judged to affect the ability to evaluate the subject, whose DBT/FFDM images were diagnostically evaluable and whose mammography images were available for independent blinded evaluation, regardless of image quality.

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: The analysis population consisted of asymptomatic adult women (\>30 years of age) scheduled for routine screening mammography. All women followed the same participant flow plan, and were all considered to be in the same single arm of the study.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Imaging Data Collected, measured over within 30 days of enrollment.

The primary endpoint is the number of participants with imaging data collected. The outcome description specifies data from both digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM), collected from asymptomatic women undergoing screening mammography. Its stated timeframe is within 30 days of enrollment, and its unit is participants.

A participant count is useful for documenting whether a recruitment and imaging-data collection objective was achieved. It can describe how many people contributed the intended imaging data, but by itself it does not measure whether either imaging method detected disease accurately. It also does not quantify the agreement between the methods, sensitivity, specificity, or any other diagnostic-performance characteristic. Those outcomes would require corresponding definitions and reported results, which are not reported in the registry record.

The endpoint's stated efficacy population is narrower than the full enrollment entry: it includes eligible subjects without protocol violations judged to affect evaluation and whose DBT/FFDM images were diagnostically evaluable. The registry record does not report the observed primary endpoint count, so the extent to which this imaging-data collection objective was met cannot be determined from the posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a participant-count endpoint, but reports no inferential analyses. The following concepts explain how such endpoints and possible comparisons are generally interpreted; they do not describe unreported methods used by this study.

What does a participant count measure?

A count records how many participants meet a specified outcome definition. Here, that definition concerns collection of DBT and FFDM imaging data within 30 days of enrollment. A count is directly interpretable as a number of people, but it does not by itself describe the quality of the images, diagnostic accuracy, or whether one imaging method performs better than another. Those questions require outcome definitions and results beyond a collection count.

Why does the analysis population matter?

The primary-outcome description identifies an efficacy population based on meeting inclusion and exclusion criteria, having no protocol violations judged to affect evaluation, and having diagnostically evaluable DBT/FFDM images. This means that the population used for an endpoint can be defined more narrowly than everyone enrolled. In general, exclusions can affect the interpretation of a result if the excluded participants differ in relevant ways from those retained. The number excluded and the handling of such participants are not reported in the registry record, so the relationship between the enrolled population and the endpoint population cannot be assessed.

How would a comparison of the imaging methods be analyzed?

As a general statistical point, measurements from two methods applied to the same person are related rather than independent. A suitable analysis would normally account for that within-person structure. The choice of method also depends on the specific diagnostic outcome, its scale, and the study's target estimand. The registry describes participants undergoing both methods, but it does not report a statistical analysis plan, diagnostic outcome definitions, or a comparative analysis. It is therefore not possible to say which method was used or whether the design's within-person structure was accounted for in an analysis.

What does a confidence interval add?

In general, a confidence interval communicates the uncertainty around an estimated effect or outcome measure. A narrow interval indicates greater precision than a wide interval, while an interval compatible with a range of effects may leave important uncertainty. No confidence interval or diagnostic-performance estimate is reported in the registry record for the primary endpoint. There is therefore no posted precision estimate to interpret, and precision for an unreported diagnostic comparison cannot be inferred from the enrollment entry.

How should the planning illustration be read?

The record's sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is stated as a fraction of the observed effect. These assumptions are explicitly an illustration, not the study's own design; they do not turn this single-group imaging-data collection study into a randomized two-arm trial. Any resulting sample-size values are planning quantities, not observed power and not evidence that the study obtained a particular effect. The record does not report the trial's own sample-size justification.

Why can over-dispersion matter?

In general, over-dispersion occurs when count data vary more than a chosen statistical model expects. If ignored, uncertainty estimates can be too small, making results appear more precise than they are. Whether over-dispersion is relevant depends on the count outcome and its distribution. The primary outcome is a count of participants, and no model or distributional analysis is reported. There is no basis in the registry record to assess over-dispersion or to claim that a particular count model was used.

What does the registry's analysis entry tell us?

The registry lists 0 analyses. That is important when reading the record: the listed endpoint definition and safety counts do not constitute a reported inferential analysis. No hypothesis test, adjustment strategy, diagnostic-accuracy estimate, or uncertainty interval is included in the record. General statistical methods can clarify what such analyses would need to address, but they cannot substitute for results or methods that are not reported.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 3 outcome measures, but only the primary outcome is described in detail in the record summarized by these registry entries. The other outcomes' definitions, timeframes, and results are not reported in the registry record. The record lists 0 analyses, so it does not establish which outcomes were tested, whether any were designated for confirmatory inference, or how multiple comparisons would have been handled.

Multiplicity arises when several outcomes, comparisons, or statistical tests are considered. In general, a larger collection of tests can increase the chance of at least one apparently positive result by chance if no adjustment or prespecified interpretation is used. The record does not report a multiplicity strategy, and no correction should be assumed. Since inferential results are not listed, multiplicity cannot be evaluated from the posted information.

The primary endpoint is restricted to eligible subjects with diagnostically evaluable DBT/FFDM images and without protocol violations judged to affect evaluation. This makes the definition of the analysis population relevant. The record does not state how missing images, incomplete imaging, or participants who did not meet the evaluability criteria were handled in an analysis. It also does not report the number of participants with missing or unevaluable data. A missing-data method, imputation strategy, or sensitivity analysis is not reported in the registry record.

These omissions limit interpretation of both the endpoint and its representativeness. The listed enrollment of 250 cannot be treated as the number analyzed for the primary outcome, and the available information does not show whether participants with complete imaging differed from those without evaluable images.

11. 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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists one safety group, “Mammography FFDM and DBT.” For serious adverse events, 250 participants are listed as at risk and 0 as affected. For other adverse events, 250 are listed as at risk and 2 as affected. The record lists 0 deaths. No top serious adverse-event terms are listed.

These figures are counts, not a complete characterization of event risk. The record does not provide details about the kinds of other adverse events, their timing, duration, severity, or whether investigators considered them related to either imaging method. The serious-event count of 0 describes the posted registry entry; it does not establish that no events occurred outside the registry's reporting definitions or observation scope.

The at-risk counts and affected counts should not be interpreted as an independent comparison between DBT and FFDM. Both methods are described as being performed in the same single-group study, and the safety entries are not presented as separate randomized groups. The registry record supplies no comparative safety analysis or uncertainty estimate. These entries therefore provide a concise descriptive account, not evidence for a causal difference between imaging methods.

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

The primary endpoint asks whether imaging data were collected from participants using both DBT and FFDM within 30 days of enrollment. This is relevant to whether the recruitment plan assembled the intended imaging material. The registry lists enrollment of 250, but does not report the observed number of participants meeting the endpoint. It is therefore not possible to determine from this record how many participants contributed the required imaging data.

The study title refers to diagnostic accuracy and performance, but the primary outcome described is data collection. Image collection is a prerequisite for many forms of diagnostic evaluation, yet it is not itself an accuracy result. The record does not report disease status, diagnostic classifications, sensitivity, specificity, agreement, or an estimate comparing DBT with FFDM. It also lists 0 analyses. As a result, the registry record does not establish whether one method was more accurate, whether their performance was similar, or how uncertain any comparison might be.

The study's single-group model and description of participants undergoing both imaging methods are important context. This structure differs from a randomized comparison between separate groups. A within-person analysis could be appropriate for some comparative questions, but the actual analysis methods are not reported in the registry record, and no comparative result is posted.

The safety entries report 0 participants affected by serious adverse events, 2 affected by other adverse events, and 0 deaths, among the listed group. These are descriptive registry counts and do not explain event details or establish causation. Taken together, the posted information describes recruitment, planned image collection, endpoint criteria, and limited safety counts. It does not answer the broader diagnostic-performance question on its own.

13. Why This Trial Matters Statistically

This trial is statistically interesting because its title raises a comparative diagnostic question, while its stated primary endpoint is a count of participants with imaging data collected. Distinguishing data availability from diagnostic performance is essential: a study may successfully collect images without that fact alone establishing the accuracy of either method. Conversely, a missing endpoint result prevents readers from assessing whether the intended imaging material was obtained.

The record also illustrates why design labels matter. Participants are described as undergoing both FFDM and DBT, while the study model is single group and allocation is listed as NA. Treating the record as a conventional randomized two-arm comparison would misstate its structure. Any method comparison would need to reflect the fact that both imaging methods are used within the participant set, but the registry does not report such an analysis.

Finally, the distinction between enrollment and analyzable outcome data is important. The listed enrollment is 250, while the primary endpoint population requires evaluable images and other eligibility conditions. Without a reported endpoint count or missing-data account, readers cannot determine how much of the enrolled population contributed usable paired imaging data. These are not minor reporting details: they determine what population an estimate would describe and how much confidence to place in a comparison.

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 is limited by the absence of a reported primary endpoint result. It describes the number of participants with imaging data collected as the primary outcome, but provides no observed count. The enrollment entry of 250 cannot replace that result, because enrollment does not establish that both image types were collected and evaluable for every participant.

The record does not report a diagnostic-accuracy outcome, a comparison of DBT with FFDM, an uncertainty interval, or a p-value. Although the trial title refers to diagnostic accuracy and performance, those results are not reported in the registry record. The record lists 0 analyses, leaving the statistical methods, estimand, and approach to the within-participant structure unspecified.

The population definition requires eligibility, absence of protocol violations judged to affect evaluation, and diagnostically evaluable images. The record does not give the number meeting those criteria, the number with missing or unevaluable images, or how those cases were handled. It also does not report details for the other outcome measures, a multiplicity strategy, or the trial's own sample-size justification.

Safety reporting is limited to counts of affected participants and those at risk, without event descriptions or causal assessments. The single-group design and lack of masking, as listed in the registry, also mean that the record should not be interpreted as a blinded randomized comparison. These limitations reflect what is and is not reported, rather than proof that additional analyses or information do not exist elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Assessment of Diagnostic Accuracy and Performance of Digital Breast Tomosynthesis Compared to Mammography — NCT02306265.
• Registry record last updated 2019-01-29; status last verified 2019-01.
• Results first posted 2019-01-29.
• 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

NCT02306265 is the ADAPT-SCR recruitment plan, sponsored by GE Healthcare. It concerns collecting DBT and FFDM images from asymptomatic women undergoing screening mammography. The registry lists enrollment of 250, a study start of 2015-05, primary completion on 2017-07-07, and status completed. The model is single group, allocation is NA, and masking is none.

The primary endpoint is the number of participants with imaging data collected within 30 days of enrollment. The observed endpoint result and diagnostic-performance analyses are not reported in the registry record; 0 analyses are listed. Safety entries list 0 participants with serious adverse events, 2 with other adverse events, and 0 deaths. These descriptive entries do not establish comparative diagnostic performance or causation.