Efficacy of Digital Breast Tomosynthesis + Standard 2- Dimensional Mammography in Breast Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy of Digital Breast Tomosynthesis + Standard 2- Dimensional Mammography in Breast Cancer (NCT03190083), a na na study. The primary outcome is Number of Participants for Which DBT Altered Surgical Plan.

2. Clinical Question

The study’s stated purpose was to assess whether DBT could contribute information about the extent of disease or additional findings in newly diagnosed breast cancer. Such findings could be relevant to staging and surgical planning, which motivated the endpoint. The primary outcome was a participant count rather than a measure of diagnostic accuracy, survival, or a comparison of treatment outcomes.

The central statistical question is therefore descriptive: how many participants had qualifying positive findings that changed surgical management? The registry record does not report that count. It also does not report the number of participants with qualifying findings that did not change management, or the total number for whom surgical planning was evaluated. Without those details, the size and precision of any observed change cannot be assessed from the registry record.

3. Trial Design

This was a completed, single-group study sponsored by Case Comprehensive Cancer Center. The registry lists 16 participants enrolled. The study began on 2017-07-01 and reached primary completion on 2018-06-13. Its phase is listed as NA, and allocation is listed as NA. Masking is listed as none.

The intervention description concerns a three-dimensional tomosynthesis mammogram. Participants were to undergo a separate two-dimensional mammogram plus DBT in addition to the standard two-dimensional mammogram. The arm description refers to patients assigned a BIRADS 5 category at the time of diagnosis and newly diagnosed breast cancer patients. The registry lists two device interventions: a two-dimensional mammogram and digital breast tomosynthesis.

The study model is single group. As a result, the design does not establish a randomized, like-for-like comparison between participants receiving DBT and participants receiving only standard two-dimensional mammography. The imaging context is an added DBT examination alongside standard imaging, rather than a separate control arm. Any change in surgical planning was intended to be counted in that single-group setting.

The primary endpoint timeframe is at completion of the three-dimensional mammogram, listed as 1 day. The registry record does not report further details about recruitment procedures, eligibility criteria, the order or interpretation of imaging, or how a change in surgical plan was adjudicated. It also does not report a trial-specific sample-size justification or a statistical analysis plan. The record lists four outcome measures and 0 analyses. The absence of an analysis entry means that a primary endpoint result cannot be read from 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

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: Participants who went on study

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants for Which DBT Altered Surgical Plan, measured over At completion of 3-Dimensional mammogram (1 day).

The primary endpoint is the number of participants for whom DBT altered the surgical plan. It is a count of participants, not a count of findings: a participant with a qualifying finding would contribute to the endpoint if that finding changed surgical management. The timeframe is completion of the three-dimensional mammogram, listed as 1 day.

The endpoint description restricts the findings considered to positive findings that require surgical intervention. Examples include an additional site of cancer or atypical pathology, including atypical ductal or lobular hyperplasia, papilloma, DCIS, or LCIS. The stated focus is therefore on information judged relevant to surgical management, rather than every imaging observation or every abnormality.

This endpoint was chosen to connect additional imaging information to a practical planning consequence. A count of participants whose plan changed can describe how often DBT findings were consequential in the enrolled group. It does not, by itself, establish that the changed plan improved outcomes, that the finding was detected only because of DBT, or that the imaging interpretation was accurate. Those questions require additional outcome definitions and analyses.

The registry record does not report the observed count for this endpoint, a denominator for its analysis, or a measure of uncertainty. Consequently, its frequency and precision cannot be evaluated from the recorded endpoint information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a count of participants with an event: the event is that DBT altered the surgical plan under the endpoint’s stated definition. In general, a binary participant outcome records whether each person meets a specified condition, and a count adds the participants who meet it. This differs from counting the number of imaging findings, because the endpoint names participants as the unit.

What does a count tell us?

A count is easiest to interpret alongside its denominator. The numerator describes how many participants experienced the defined event; the denominator describes how many participants were assessed for that event. Together they can describe the observed frequency in the analyzed group. Here the registry record supplies the endpoint definition and the enrollment figure, but it does not report the endpoint count or its analysis denominator. Enrollment alone cannot establish how many participants were evaluable for this outcome.

In general, a confidence interval expresses the uncertainty around an estimate under the assumptions of the method used. For a binary outcome, an interval around a proportion can show how uncertain an estimated event frequency is, especially when the group is small. No confidence interval or primary endpoint estimate is reported in the registry record, so there is no interval to interpret. A p-value would address a specified statistical hypothesis under a specified analysis; neither a primary endpoint p-value nor the analysis that would produce one is reported.

Why does the study design matter?

This study is described as single group, with allocation NA and masking none. DBT was evaluated in addition to standard two-dimensional mammography. In general, a single-group count can describe what was observed among participants in that group, but it cannot by itself estimate a randomized contrast with a separate control group. Differences that might be attributed to an imaging strategy cannot be separated from other influences through random allocation in this design. The registry does not report a comparison analysis.

The endpoint is also a management outcome rather than a direct measure of diagnostic accuracy. In general, diagnostic accuracy requires a defined reference standard and a way to classify test findings against that standard. A recorded change in surgical planning instead captures a consequence of findings judged positive and requiring intervention. The registry description does not report a reference standard, sensitivity, specificity, or a formal accuracy analysis. It would therefore be inappropriate to interpret a plan-change count as an accuracy measure.

How should the planning assumptions be read?

The stated planning illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes an effect to detect as a stated fraction of the observed effect. These are assumptions for an illustration, not a reported account of how this single-group study was designed. The registry record does not report a trial-specific sample-size justification or state that the study enrolled two randomized arms.

In general, sample-size planning asks how much information a proposed study may need to detect a defined effect under specified assumptions. A planning illustration is conditional on its assumed effect, outcome, design, and analysis. It does not say what happened in the enrolled participants, and it is not observed power. An illustration framed around equal allocation between two arms does not describe the allocation of participants in a registry-listed single-group study. No conclusion about whether the enrolled group was adequately sized for the primary endpoint can be drawn without the trial’s own justification and analysis plan.

The endpoint is listed as a count, and the record lists 0 analyses. The registry record does not report model-based estimates, adjustment for covariates, handling of repeated observations, or a method for missing outcome data. In general, model choice should follow the outcome structure and design. A count of participants with a binary event may be analyzed descriptively, but any inferential method requires a defined denominator and assumptions about how observations were collected. No particular inferential procedure should be attributed to this study from the available record.

Over-dispersion is a general concern in count-data modeling when variability exceeds what a model assumes. It can affect uncertainty estimates if a model for counts is used. It is not possible to determine whether over-dispersion is relevant to this endpoint from the registry information: the endpoint counts participants with an event, and no fitted model or distributional assessment is reported. The key issue for interpretation remains that the endpoint result and its analysis are not reported.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("3-dimensional Tomosynthesis Mammogram")
n      <- c(16)
events <- c(0)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  3-dimensional Tomosynthesis Mammogram  16  0  0.0  0.0  20.6  0.0  19.4  0.1  19.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures and 0 analyses. The primary outcome is identified as the number of participants for whom DBT altered the surgical plan. The registry record does not provide numerical results for that endpoint or enough detail to assess the results of the other outcome measures.

When a study evaluates multiple outcomes or multiple hypotheses, multiplicity can increase the chance of finding an apparently notable result by chance if many tests are interpreted together. In general, an analysis plan may identify a primary outcome, specify which other outcomes are secondary, and describe whether or how multiplicity will be addressed. The registry record does not report a multiplicity strategy, a testing hierarchy, or an adjustment method. It is not possible to determine whether such procedures were planned or used.

The registry record also does not report how missing endpoint data were handled, how many participants had missing or unevaluable assessments, or whether the endpoint denominator differed from enrollment. No analysis population is described, such as a defined group of participants included in the primary analysis. These details matter because exclusions or incomplete assessments can change the group represented by an endpoint count.

Interim analyses and stopping rules are not reported in the registry record. Neither should be inferred from the absence of an analysis entry. Overall, the record leaves the analysis population, missing-data approach, multiplicity handling, and analysis procedures unspecified. With 0 analyses listed, no statistical adjustment or set of outcome-specific findings can be evaluated.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry lists 16 participants at risk for serious adverse events in the three-dimensional tomosynthesis mammogram group and reports 0 serious adverse events. It lists 16 at risk for other adverse events and reports 0 other adverse events. The death count is 0. No serious adverse event terms are listed.

These figures are event counts recorded for the study, with the corresponding numbers at risk as stated in the registry. They do not describe the primary endpoint, which concerns changes to surgical planning. The figures also do not establish that no adverse effects of any kind occurred; the registry record reports the categories and counts shown, and does not provide further detail about safety surveillance, event definitions, or completeness of reporting.

In general, a zero count in a small study should be interpreted as no events recorded in the listed group, not as proof that an event is impossible or that risk is absent. The registry record does not report an estimated risk with an uncertainty interval. The safety entries therefore support a narrow description of recorded serious events, other events, and deaths, rather than a broad conclusion about safety.

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

The study addresses whether adding DBT to standard two-dimensional mammography could reveal positive findings relevant to the extent of disease and surgical planning in newly diagnosed breast cancer. Its primary endpoint was designed to count participants whose surgical plan changed because of qualifying findings. The registry record does not report the observed endpoint count, so it cannot establish how often such a change occurred in this group.

The available record does establish the study’s single-group design and enrollment of 16 participants. It also describes the intended imaging context and defines the kinds of positive findings considered relevant to the primary endpoint. These details clarify what the study set out to measure, but they are not a substitute for a reported result.

Even a reported number of plan changes would answer a limited question. It would describe a management change in the participants assessed, not whether the changed plan improved health outcomes, whether all additional findings were correct, or whether DBT was superior to standard imaging in a randomized comparison. Those broader questions require outcome data and comparisons not reported in the registry record.

The safety entries report 0 serious adverse events, 0 other adverse events, and 0 deaths among the listed groups of 16 at risk. Those counts describe what the registry records and should not be expanded into a claim that every possible harm was excluded.

Accordingly, the record supports a description of the study’s purpose, design, endpoint, and recorded safety counts. It does not support a quantitative conclusion about the primary endpoint or the clinical effect of adding DBT. The missing result is central: without it, the frequency and precision of endpoint events cannot be judged.

14. Why This Trial Matters Statistically

This study illustrates why an endpoint definition and an endpoint result are different kinds of information. The registry gives a specific primary question: count the participants for whom DBT altered surgical planning because of positive findings requiring intervention. That definition identifies the event of interest, but it does not reveal how many participants experienced it.

The distinction between enrollment and an analysis denominator is also important. The registry lists enrollment of 16, but does not report how many participants contributed data to the primary endpoint. An enrolled group size cannot automatically be substituted for the number assessed or analyzed. Without a reported denominator, a count could not be translated into an interpretable frequency even if the numerator were available.

The design adds another statistical consideration. Because the study is single group, its central endpoint is descriptive in the registry record rather than a result from randomized arms. The imaging question concerns DBT added to standard two-dimensional mammography, but that does not create an independent control group. Design and analysis must be understood together when judging what a result could establish.

Finally, planning illustrations should not be confused with observed evidence. The stated planning assumptions describe a two-arm, equal-allocation framework and a normal approximation, whereas the registry lists a single-group model. Such an illustration may help explain conditional planning concepts, but it is not the study’s observed power or proof that the actual design followed those assumptions. The absence of a reported primary result limits interpretation more than the existence of a planning calculation can resolve.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The principal limitation for statistical interpretation is that the registry record does not report the primary endpoint result. It lists the endpoint definition but no participant count, analysis denominator, confidence interval, or test result. Therefore, the intended descriptive question cannot be answered from the record.

The registry describes a single-group study with allocation NA and masking none. It does not report a randomized comparison group. This limits the scope of any potential inference: a count of plan changes in the enrolled group would not, on its own, quantify a comparative effect against a separate group receiving standard imaging only.

The record lists 16 participants enrolled, but does not state how many had complete imaging or endpoint assessments, or how many were included in an analysis. Eligibility and assessment details are not reported beyond the arm description. The registry also does not report procedures for interpreting imaging, confirming positive findings, or determining whether a surgical plan changed because of a finding.

Four outcome measures are listed, but the record reports 0 analyses. A statistical analysis plan, handling of missing data, analysis populations, multiplicity procedures, and interim analyses are not reported in the registry record. The planning assumptions describe a two-arm equal-allocation illustration, which is not the listed single-group design; no trial-specific sample-size justification is reported.

Finally, the safety entries are limited to the recorded categories and counts. The registry reports 0 serious adverse events, 0 other adverse events, and 0 deaths, but provides no further safety ascertainment details. These limitations restrict what can be concluded from the registry record and should not be filled by assumptions.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Efficacy of Digital Breast Tomosynthesis + Standard 2- Dimensional Mammography in Breast Cancer — NCT03190083.
• Registry record last updated 2022-06-27; status last verified 2022-06.
• Results first posted 2020-04-10.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT03190083 is a completed, single-group study sponsored by Case Comprehensive Cancer Center, with 16 participants enrolled. It evaluated digital breast tomosynthesis in addition to standard two-dimensional mammography in newly diagnosed breast cancer patients. The primary endpoint was the number of participants for whom DBT altered surgical planning because of qualifying positive findings.

The registry lists four outcome measures and 0 analyses. It does not report a numerical primary endpoint result, analysis denominator, or statistical analysis plan. The safety record lists 0 serious adverse events, 0 other adverse events, and 0 deaths among 16 participants at risk in the listed group. These details describe the registry entry but do not establish the frequency of surgical-plan changes or the clinical effect of adding DBT.