Stem Cell Transplant for Hematological Malignancy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Stem Cell Transplant for Hematological Malignancy (NCT00176930), a non-randomized na study. The primary outcome is Number of Participants Experiencing Disease-Free Survival at 2 Years Post Transplant.

2. Clinical Question

The study's stated purpose was to develop a standard-of-care treatment using allogeneic stem cells for patients with blood cancers. The broad range of conditions and transplant pathways means the clinical question is not a single comparison between one treatment and one control. Rather, the record describes several approaches within a transplant program. The reported primary outcome concerns disease-free survival after transplant, while secondary outcomes address engraftment, graft-versus-host disease, relapse or persistence of malignancy, survival, and engraftment failure.

3. Trial Design

This is a non-randomized study with no masking and a single-group model in the registry's design classification. The record lists an enrollment of 330 and identifies the study as terminated. The study start is recorded as 2001-10, with primary completion recorded as 2019-12. Its phase is listed as NA. These administrative details describe the registry entry; they do not establish that every enrolled participant contributed data to every outcome.

The treatment groups vary by transplant-cell source and preparative regimen. Several groups receive cyclophosphamide, total body irradiation, and peripheral blood stem cells, bone marrow, or umbilical cord blood. Groups for people unable to receive total body irradiation use cyclophosphamide and busulfan with one of those cell sources. Another cord-blood group adds ATG for participants who had not received chemotherapy in the prior 3 months. A co-enrollment group receives cyclophosphamide, total body irradiation, CD4+/CD25+ cells, and peripheral blood stem cells, and is described as co-enrolled on another trial.

Because allocation is non-randomized, the groups may differ in clinical characteristics, eligibility, treatment history, or reasons for receiving a particular regimen. The registry record does not report enough information to assess these potential differences or to treat the groups as exchangeable. Any crude differences between groups would therefore be descriptive, not evidence that one regimen caused better or worse outcomes than another.

The record states that the protocol was revised to reflect that the study was considered “treatment guidelines,” rather than a research study. It does not report further detail about the implications of that revision for the analyses. Although 10 outcome measures are recorded, the registry record reports no analyses. The statistical analysis plan, handling of the different transplant groups, and rationale for the enrollment target are 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.

Before assignment: One patient withdrew consent.

Only the first 6 of 8 groups are shown.

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.

Only the first 6 of 9 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Experiencing Disease-Free Survival at 2 Years Post Transplant, measured over 2 years.

The primary endpoint is the number of participants experiencing disease-free survival at 2 years post transplant. The record describes disease-free survival as a period during and after treatment in which the disease being treated does not get worse. In cancer studies, this type of outcome is used to describe whether disease progression or recurrence has occurred over a defined follow-up period. It complements an overall-survival outcome because it focuses on disease status as well as the passage of time without worsening.

The registry names the outcome as a count of participants, rather than reporting a proportion, rate, or time-to-event estimate. A count alone is difficult to interpret without the number of participants assessed, the definition of disease-free survival used in the study, and the way deaths, relapse, missing follow-up, and censoring were handled. Those details are not reported in the registry record. The record also does not give the primary endpoint result, a confidence interval, or an analysis population for this outcome.

The specified time frame is 2 years. That gives the outcome a defined follow-up horizon, but does not by itself establish whether every participant had complete follow-up through that point. The secondary outcomes include survival at 2 years and 5 years, relapse or persistence at 2 years and 5 years, and transplant-related outcomes. They provide related measures, but are distinct from the primary disease-free-survival count and do not replace its missing result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Several statistical ideas help clarify what can and cannot be learned from this record. These are general explanations; the registry does not report a complete analysis plan or results for the primary endpoint.

What does a non-randomized design imply?

In a randomized trial, assignment by chance is intended to make groups comparable, on average, with respect to factors that may affect outcomes. In a non-randomized study, treatment choice or group membership may depend on clinical circumstances. For example, this record distinguishes participants unable to receive total body irradiation and identifies a cord-blood group with a treatment-history condition. Those design features indicate that groups are not automatically comparable. Even when two groups have different outcome counts, the difference can reflect their starting characteristics or selection into treatment, as well as any treatment effect.

The registry classifies the study as single-group while also listing multiple treatment groups. These labels should not be converted into an assumption of a controlled comparison. The design details available in the record describe treatment pathways, but do not report a randomized control arm or an adjusted comparative analysis. Adjustment methods can sometimes account for measured differences, but they cannot guarantee removal of bias, and no such method is reported in the registry record.

What would a confidence interval tell the reader?

In general, a confidence interval expresses the statistical uncertainty around an estimate under the assumptions of the analysis. A narrower interval indicates greater precision, while a wider interval indicates less precision. For a count or a proportion, interpretation also depends on the denominator and the model used. For a time-to-event outcome, follow-up and censoring matter. The registry record does not report a confidence interval or the information needed to calculate one for the primary endpoint. No interval should be inferred from the enrollment figure or from safety counts.

Why distinguish a count from a rate or time-to-event estimate?

A count states how many events or outcomes were recorded, but it does not give the chance of the outcome without a denominator. A proportion relates a count to the number of participants assessed. A time-to-event method additionally uses the timing of events and can account for participants whose follow-up ends before an event is observed, subject to its assumptions. The primary outcome is described as a count of participants with disease-free survival at 2 years. The record does not report a corresponding denominator, a time-to-event estimate, or its handling of incomplete observation. Thus the endpoint label alone does not reveal the statistical method used.

How should sample-size planning be read?

Sample-size calculations are prospective planning tools: they describe how many observations might be needed under specified assumptions to detect a chosen effect with a chosen level of statistical sensitivity. The record's planning assumptions specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They also describe the effect as a stated fraction of the observed effect. These are planning assumptions, not observed trial results. The record is non-randomized and lists several transplant groups, so a hypothetical equal-allocation, two-arm calculation should not be mistaken for the study's actual design.

Such calculations are conditional on the assumed effect and statistical model. If the true effect differs from the planning value, or if the analysis differs from the assumed design, the calculation may not describe the study's sensitivity. The observed primary outcome effect and the rationale for the enrollment target are not reported in the registry record. Sample-size illustrations are not observed power: observed power is not a substitute for reporting an effect estimate and its uncertainty.

Why does multiplicity matter?

When a study evaluates many outcomes or makes many comparisons, the chance of finding at least one apparently noteworthy result by chance can increase. Statistical approaches to multiplicity may define a primary outcome in advance, adjust significance thresholds, or use a hierarchical testing strategy. The record identifies a primary outcome and lists secondary outcomes, but does not report a multiplicity strategy or statistical testing plan. It also reports no analyses, so there are no posted p-values to interpret in light of multiple testing.

What does over-dispersion mean in general?

For count data, a simple model may assume that variability follows a particular relationship with the average count. Over-dispersion means the observed variability is greater than that model expects. If ignored, standard errors can be too small and intervals or tests can appear more certain than warranted. This general issue may matter in count analyses, but the registry record does not report a count model, an over-dispersion assessment, or a fitted analysis for the primary endpoint. No specific model should be attributed to the study.

The registry therefore supports methodological description, but not a reconstruction of the primary statistical analysis. The endpoint definition, analysis population, missing-data approach, model, covariate adjustment, and uncertainty estimates are not reported in the registry record.

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("PBSC: No TBI", "Marrow : No TBI", "UCB : No TBI", "UCB : No TBI/Bu/Cy/ATG", "PBSC", "Marrow")
n      <- c(12, 13, 1, 1, 213, 85)
events <- c(4, 9, 0, 0, 100, 52)
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  PBSC: No TBI  12  4  33.3  9.9  65.1  13.8  60.9  13.9  61.4
ARM  Marrow : No TBI  13  9  69.2  38.6  90.9  42.4  87.3  41.9  87.2
ARM  UCB : No TBI  1  0  0.0  0.0  97.5  0.0  79.3  1.3  84.2
ARM  UCB : No TBI/Bu/Cy/ATG  1  0  0.0  0.0  97.5  0.0  79.3  1.3  84.2
ARM  PBSC  213  100  46.9  40.1  53.9  40.4  53.6  40.4  53.7
ARM  Marrow  85  52  61.2  50.0  71.6  50.5  70.8  50.5  70.8

11. Multiplicity, Missing Data and Analysis Populations

The registry records one primary outcome and a set of secondary outcomes covering engraftment, graft-versus-host disease, relapse or persistence of malignancy, survival, and engraftment failure. It reports 10 outcome measures, but the results information states no analyses. The outcome list should therefore be read as a record of measures, not as evidence that each was analyzed or that any result met a statistical criterion.

Multiplicity is the general problem created when many outcomes or comparisons are examined: even if no true effect exists, some results can appear notable by chance. A prespecified primary outcome can help focus interpretation, while a stated testing strategy can explain how secondary outcomes are handled. The multiplicity strategy, any planned hierarchy, and any adjustment for multiple testing are not reported in the registry record. Without analyses or p-values, there is no basis for assessing the impact of multiplicity on specific findings.

Missing-data handling is also not reported. The record does not state how incomplete follow-up, withdrawal, death before assessment, or unavailable outcome measurements were handled for disease-free survival. Nor does it report the number included in the primary analysis, whether the analysis followed an intention-to-treat principle, or how the safety populations were defined. These omissions matter because the number enrolled may differ from the number with an observed outcome.

The record does not report a statistical analysis plan, methods for adjustment, or methods for handling censored observations. Therefore, assumptions about these procedures should not be made from the endpoint names or the study design description.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: death (9.4%), graft versus host disease (8.3%), primary graft failure (8.3%), relapse (8.3%), hemorrhage (0.5%).

The serious-event listings are counts associated with the treatment groups, including numbers at risk and numbers affected. These are descriptive safety figures. They do not establish that an event was caused by transplantation or by a particular component of a regimen, and they do not provide a randomized comparison. Group sizes and clinical characteristics differ, so raw counts should not be compared as if the groups were equivalent.

The registry's listed top serious terms include Death at 9.4%, Graft versus host disease at 8.3%, Primary Graft Failure at 8.3%, Relapse at 8.3%, Hemorrhage at 0.5%, and Syndromes at 0.5%. These percentages are registry-listed figures. Their specific denominators, observation windows, and relationship to the treatment groups are not reported in the registry record. They should not be treated as risk estimates for an individual participant or as comparative treatment effects.

The group-level safety fields also include deaths and serious and other affected counts. These counts describe recorded events, but the record does not provide enough detail to determine whether participants could contribute more than one event, how events were adjudicated, or whether ascertainment was comparable across groups. Safety summaries should therefore be interpreted as registry descriptions rather than causal evidence.

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

The record identifies a clinically important outcome: disease-free survival at 2 years after allogeneic transplant. It also documents a range of transplant approaches and names outcomes relevant to engraftment, relapse, graft-versus-host disease, and survival. This helps describe the scope of the treatment program and the outcomes the registry intended to track.

However, the primary endpoint result is not reported in the registry record. There is no reported count of participants with disease-free survival at 2 years, no denominator, and no uncertainty estimate. The record therefore does not quantify the primary outcome or establish the degree of precision of an estimate. The outcome definition alone is not a result.

The design also limits comparative interpretation. The study is non-randomized and has several treatment pathways, including groups defined by ability to receive irradiation, transplant-cell source, and treatment history. Differences between groups could arise from those characteristics or other factors, not only from the regimen. The registry does not report an adjusted analysis that would address such differences, and it reports no analyses at all.

The safety listings provide descriptive counts and registry-listed percentages for selected serious terms. They do not show that treatment caused those events, nor do they establish that one regimen has a different safety profile from another. Denominators and observation details for the listed percentages are not reported in the registry record.

Accordingly, this record supports understanding of the study's design, treatment groups, planned outcomes, and selected safety reporting. It does not support a claim that a treatment worked or failed, a quantitative estimate of disease-free survival, or a causal comparison among transplant approaches. The result needed to answer the primary clinical question is not reported in the registry record.

14. Why This Trial Matters Statistically

This study is statistically instructive because it shows why a registry entry's design and outcome labels must be separated from evidence about treatment effects. A primary endpoint can be clearly named without a result being available. Here, the primary outcome is disease-free survival at 2 years, but the record does not report its count, denominator, or uncertainty. Readers should not infer an efficacy result from the presence of the endpoint description.

The record also illustrates the interpretive limits of non-randomized treatment groups. Several approaches are described, but these pathways are not like-for-like control groups. Eligibility and treatment-history distinctions may influence which approach a participant receives. Without randomization or a reported adjusted analysis, observed group differences would not by themselves identify a causal treatment effect.

A further lesson is that enrollment is not an outcome denominator. The registry records an enrollment of 330, yet the number with an assessable primary outcome and the number included in any analysis are not reported. For clinical interpretation, outcome counts need clear denominators, follow-up definitions, and a description of missing data. Without them, even a stated count can be difficult to translate into an estimated probability.

Finally, the safety listings illustrate the difference between describing events and attributing them to treatment. Counts and percentages can help characterize what was recorded, but interpretation depends on the population at risk, event definitions, follow-up, and comparability of groups. Those details are not fully reported in the registry record. The central statistical contribution of a careful reading is therefore not a treatment verdict, but a clear account of what the registry does and does not quantify.

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 registry record leaves several trial-specific limitations unresolved. It does not report detailed eligibility criteria, baseline characteristics, or the reasons participants entered particular transplant groups. Given the non-randomized design and the variation in cell source and preparative regimen, these details would be important for assessing comparability and selection effects.

The primary endpoint result, its denominator, and its analysis population are not reported. The record does not explain how disease-free survival was operationalized, how events were timed, or how death, relapse, incomplete follow-up, and censoring were treated. Without this information, neither the endpoint count nor its precision can be evaluated.

The study is listed as terminated, and the protocol was revised to reflect treatment guidelines rather than a research study. Further information about how that revision affected recruitment, outcome collection, or statistical analyses is not reported in the registry record. The rationale for the enrollment target and any sample-size justification are also not reported.

Although the record lists multiple secondary outcomes and safety figures, it does not report analyses, a statistical analysis plan, covariate adjustment, a multiplicity approach, or missing-data methods. The denominators and observation windows behind the top serious-event percentages are not reported in the registry record. These limitations restrict both descriptive interpretation and any attempt at causal comparison.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Stem Cell Transplant for Hematological Malignancy — NCT00176930.
• Registry record last updated 2021-01-22; status last verified 2020-12.
• Results first posted 2021-01-22.
• 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

The registry describes a terminated, non-randomized, unmasked, single-group study of allogeneic transplantation for hematological malignancies. Enrollment is recorded as 330; the study began in 2001-10, with primary completion in 2019-12. The listed treatment groups vary by preparative regimen and transplant-cell source, with additional group-specific conditions.

The primary outcome is the number of participants experiencing disease-free survival at 2 years post transplant. Secondary outcomes cover engraftment, graft-versus-host disease, relapse or persistence, survival, and engraftment failure. The record reports 10 outcome measures and no analyses. The primary endpoint result, analysis population, missing-data methods, and statistical analysis plan are not reported in the registry record. Safety listings include group-level counts and selected serious-event percentages, which are descriptive and do not establish causal treatment effects.