Radiation Therapy Alone for the Treatment of Stage 1 and 2 Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Radiation Therapy Alone for the Treatment of Stage 1 and 2 Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma (NCT04465162), a na phase 2 study. The primary outcome is Relapse-free Survival (RFS).

2. Clinical Question

The trial asks whether radiation therapy alone can be studied as a treatment approach for patients with stage 1 or stage 2 MALT lymphoma, with relapse-free survival as the primary endpoint. Its registry summary also describes interest in treatment side effects and the possibility of a high cure rate. Those aims are not themselves evidence of a treatment effect: the registry record does not report a numerical relapse-free survival estimate, a confidence interval, or an efficacy analysis.

This design can describe outcomes among participants in the treatment group, but it cannot by itself establish how those outcomes compare with what would have occurred under a different treatment. A single-group result also cannot separate the treatment experience from other influences on outcome. The registry record does not report participant-level characteristics or an analysis adjusting for them, so the extent to which the enrolled group represents the broader population described by the eligibility conditions is not established.

3. Trial Design

This is a phase 2, single-group study sponsored by M.D. Anderson Cancer Center. The registry lists enrollment as 75, allocation as NA, and masking as none. Its status is completed. The recorded study start is 2000-06-07 and the primary completion date is 2021-03-15. These dates describe the study record and do not supply a numerical estimate of the primary outcome.

The treatment group is described as receiving radiation therapy alone. The arm description states that treatment is given QD 5 times weekly over 3.5-5 weeks. No separate control arm is listed. Because the design has no randomized comparator, comparisons between this group and an external group would require information and assumptions not reported in the registry record. The design should therefore be read as a report of outcomes within the treatment group, not as a head-to-head estimate of comparative efficacy.

The primary outcome is median relapse-free survival, measured in months, with a 95% confidence interval. Its timeframe is through study completion, up to 10 years. The registry also identifies median progression-free survival, progression-free survival at 10 years, and overall survival at 10 years as secondary outcomes. Four outcome measures are listed in total. The record identifies Kaplan-Meier estimation for survival distributions, but it does not report numerical outcome estimates or analyses.

The enrollment figure is not, on its own, a statement that all listed participants received treatment, completed follow-up, or entered every outcome analysis. Numbers actually treated, included in each analysis, and followed for each endpoint are not reported in the registry record. Nor are eligibility criteria beyond the listed conditions, participant baseline characteristics, or reasons for any exclusions reported. Those omissions limit assessment of how the registry enrollment relates to the analyzed population.

The completed status means that the registry lists the study as completed; it does not mean that every planned result is available in the record. In particular, the record does not report the primary endpoint estimate, confidence interval bounds, or outcome-specific analysis counts. The absence of these results should be kept separate from the design description: a clearly named endpoint and a completed study do not substitute for its numerical result.

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: 75 participants enrolled in study, 2 participants did not receive Radiation Therapy(RT); 1 owing to discovered stage III disease and 1 who chose observation after complete surgical resection of disease in a gastric polyp.

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.

6. Primary Endpoint

The registry lists the primary outcome as Relapse-free Survival (RFS), measured over Through study completion, up to 10 years.

The primary endpoint is relapse-free survival, abbreviated RFS, reported as a median in months with a 95% confidence interval. The registry defines RFS as time from study entry until the last follow-up or death, with all deaths censored. Kaplan-Meier curves were estimated for the survival distributions. The stated observation timeframe is through study completion, up to 10 years.

As a general statistical concept, a time-to-event endpoint records how long it takes for a defined event to occur. A median time-to-event estimate describes the point at which the estimated survival distribution reaches its midpoint; it is not the average follow-up time. A confidence interval expresses uncertainty around an estimated quantity under the assumptions of the analysis. Its width helps readers assess how precise the estimate is, while the estimate itself describes the observed outcome pattern under the endpoint definition.

Kaplan-Meier methods are generally used to estimate an outcome distribution while accounting for participants whose event status is not observed through the end of follow-up. Such participants may contribute information up to their last known follow-up, after which their later event status is unknown. The registry definition specifically says that all deaths are censored for RFS. The rationale for that definition, and how it was implemented in the analysis, are not reported in the registry record.

The endpoint's numerical median and 95% confidence interval are not reported in the registry record. Consequently, the endpoint definition can be described, but the magnitude and precision of the trial's RFS estimate cannot be assessed from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is time-to-event data. In general, time-to-event methods account for the fact that participants can have different lengths of observation and that some may not have a recorded event by the end of their follow-up. The event definition determines what the analysis estimates. For this trial, the registry calls the endpoint relapse-free survival and defines the time origin as study entry. It says time continues until last follow-up or death, with all deaths censored. That definition is essential to interpretation: the endpoint is not simply a count of relapses, and the stated handling of death is part of the estimand described by the record.

The record says Kaplan-Meier curves were estimated for survival distributions. As a general explanation, the Kaplan-Meier estimator updates an estimated probability of remaining event-free at observed event times, while retaining participants who are censored in the risk set until their last observed time. Censoring is not the same as an observed event. It indicates that the event time is not known beyond the last observation. Standard interpretation generally relies on assumptions about the censoring process; the assumptions and diagnostic checks used in this study are not reported in the registry record.

The primary endpoint is summarized as a median in months, with a 95% confidence interval. In general, a median survival time is the time at which the estimated probability of remaining event-free reaches one half. A confidence interval gives a range of values compatible with the estimate under the method's assumptions and indicates statistical uncertainty. It does not describe the range of individual participants' outcomes. The registry record identifies this summary but does not report the median or confidence interval limits. No numerical precision assessment is consequently possible.

The endpoint timeframe is through study completion, up to 10 years. That maximum timeframe does not show that every participant was followed for the maximum duration. In a time-to-event study, follow-up can vary, and the number still under observation can change over time because of events, censoring, or incomplete observation. The registry does not report numbers at risk over time, event counts for RFS, or individual follow-up information. Those missing details prevent assessment of how much information supports any part of the survival curve.

Death handling deserves separate attention. The registry explicitly states that all deaths are censored for RFS, even though death is also described as the endpoint's terminal time in the definition. The record does not explain the rationale or provide further operational detail. A statistical reading should preserve the stated definition rather than silently assume that death was counted as an RFS event. The safety listing's count of deaths is not interchangeable with an RFS event count.

The registry identifies median progression-free survival, progression-free survival at 10 years, and overall survival at 10 years as secondary outcomes. These outcomes have distinct meanings in general: progression-free survival concerns time without progression or another endpoint-defined event, while overall survival concerns time to death. Their exact event definitions and analysis details are not reported in the registry record. The record also does not give their estimates or confidence intervals, so no numerical comparison among the primary and secondary outcomes can be made.

Several statistical planning concepts are described in the record's planning assumptions. As a general matter, a significance level sets a threshold for a statistical test, allocation describes how participants are distributed across groups, and a normal approximation is a mathematical method used to estimate quantities under specified conditions. The planning illustration states a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It is explicitly a planning illustration computed from an observed effect, not the trial's own design. The trial itself is a single-group study, so the hypothetical two-arm planning assumptions do not describe its actual allocation or a randomized comparison.

The planning description says that the effect to detect is a stated fraction of the observed effect. For time-to-event planning, it says that the displayed quantities concern the total number of events; for other outcomes they concern participants per arm. These distinctions explain what a planning quantity represents, but no specific planning results or effect fractions are included in the registry record for this analysis. Such illustrations are not observed power: observed power is not a substitute for reporting an estimated treatment effect and its uncertainty. The trial's own sample-size justification and design assumptions are not reported in the registry record.

Over-dispersion is a general issue for some count outcomes: observed variability can exceed what a simple model assumes, making standard errors and uncertainty estimates too small if the extra variability is ignored. That concept cannot be applied to the RFS endpoint as though it were a count outcome, and the registry does not report a count-model analysis. More broadly, the analysis methods beyond Kaplan-Meier estimation, including any model-based or adjusted analyses, are not reported. No hazard-ratio results are listed in the record.

The registry record also does not report methods for confidence interval construction, handling of missing observations, analysis-population definitions, or checks of model assumptions. These details can affect how an estimate is calculated and which participants contribute information. Their absence does not establish that such methods were not used; it means they cannot be evaluated from the record. The most defensible statistical reading is therefore limited to the stated endpoint definition and method, without adding unreported analytical choices or results.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint, relapse-free survival, and three secondary outcomes: median progression-free survival, progression-free survival at 10 years, and overall survival at 10 years. Multiple outcomes can raise a multiplicity question: when several hypotheses are tested, the chance of at least one apparently notable result can increase. As a general statistical practice, investigators may define a testing hierarchy or adjust interpretation for multiple comparisons. Whether either approach was planned or used is not reported in the registry record.

The record reports 0 analyses. It does not provide outcome-specific estimates, confidence intervals, p-values, a testing sequence, or a multiplicity adjustment. The endpoint list should therefore be read as a list of planned or registered outcomes, not as a set of reported findings. It is not possible to determine from this record whether the primary outcome was analyzed before secondary outcomes or how any multiple testing was handled.

Missing-data and analysis-population details are also not reported. The enrollment figure is 75, but the record does not state how many participants were treated, eligible for each endpoint analysis, excluded, or included in an analysis population. Reasons for missing measurements or incomplete follow-up are not given. The RFS definition does specify that deaths are censored, but that statement does not describe other missing-data procedures or establish how censoring was implemented.

As a general concept, censoring preserves information up to the last known follow-up without treating the participant's later status as known. Its validity depends on assumptions about why observation ends. The registry record does not report checks of those assumptions, follow-up completeness, or sensitivity analyses. These omissions limit evaluation of the reliability and potential bias of any survival estimate; in this case, the numerical estimate itself is also not reported.

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 1% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists a treatment group with 73 participants at risk for each of the serious and other adverse event categories. It reports 0 participants affected by serious adverse events, 28 affected by other adverse events, and 11 deaths. These are descriptive figures attached to the treatment group. They do not establish that an event was caused by radiation therapy, and they should not be treated as a comparison between treatments.

The categories should not be conflated. A report of 0 participants affected by serious adverse events does not mean that no adverse events of any kind occurred; the record separately reports 28 affected by other adverse events. The deaths are listed separately, and the record does not state their causes or whether they were considered adverse events. The RFS definition says all deaths are censored, so the safety death count should not be read as an RFS event count.

The registry record does not give event terms for the treatment group beyond these category counts; no top serious-event terms are listed. It also does not report timing, duration, severity detail beyond the category labels, recurrence, treatment relatedness, or the methods used to collect and classify events. The recorded at-risk figure is 73, whereas enrollment is listed as 75; the record does not explain that difference. Without those details, the counts offer a limited description of reported safety information, not a complete account of the treatment group's safety experience.

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

The record establishes that a phase 2, single-group study of radiation therapy alone for stage 1 and stage 2 MALT lymphoma was registered as completed. It defines relapse-free survival as the primary endpoint, specifies a median and 95% confidence interval as the intended summary, and states that Kaplan-Meier curves were estimated. It also lists secondary survival outcomes and selected adverse-event and death counts.

It does not report the numerical primary endpoint result. The median RFS, confidence interval bounds, event count, and analysis population are not reported in the registry record. Numerical results for the secondary outcomes are also absent. Thus, the record does not support a quantitative statement about the duration or precision of RFS or the other listed survival outcomes. The stated study aim, including interest in a high cure rate, should not be mistaken for an observed result.

Even if a within-group survival estimate were available, a single-group design would describe outcomes among participants who received the study treatment, not the difference between that treatment and a concurrent comparator. Without random allocation to a comparison group, an outcome cannot be attributed to the intervention by the design alone. This is a design limitation, separate from the lack of numerical results in the registry record.

The safety counts indicate that the record lists 0 participants affected by serious adverse events, 28 affected by other adverse events, and 11 deaths, among a group with 73 at risk for each adverse-event category. These counts do not identify causes, timing, or treatment relatedness. They cannot establish whether deaths were caused by treatment, nor can they resolve the endpoint's stated censoring of all deaths.

The strongest interpretation is therefore descriptive and limited: the registry documents a completed single-group study, its treatment schedule, endpoint definitions, and certain safety counts, while leaving key efficacy estimates and analytical details unreported. It does not provide a randomized comparative effect or enough numerical outcome information to assess the primary endpoint's magnitude and precision.

13. Why This Trial Matters Statistically

This trial is statistically instructive because its registry record distinguishes a defined outcome from a reported outcome. Relapse-free survival is specified in detail as the primary endpoint, including the time origin, censoring statement, summary measure, confidence interval, and timeframe. Yet the numerical estimate is not reported. A sound statistical account must distinguish what an analysis was intended to measure from the results needed to evaluate its magnitude and uncertainty.

The single-group design also clarifies the difference between describing an outcome and estimating a treatment contrast. In a one-group study, a survival distribution can describe the participants' observed course under the study conditions. Without a concurrent comparator, that distribution does not identify what would have happened to a comparable group receiving another approach. The design limits causal and comparative interpretation irrespective of how clearly the endpoint is defined.

The death-censoring detail matters because event definitions determine the meaning of a time-to-event estimate. The registry says all deaths are censored for RFS, while also listing deaths in the safety data. Keeping these reporting contexts separate prevents a safety count from being incorrectly treated as an RFS event count. The record does not explain the endpoint convention or provide enough detail to assess how it was applied.

Finally, the planning assumptions illustrate why sample-size calculations must be separated from observed findings. The planning illustration uses hypothetical two-arm assumptions, while the actual study is single-group. Such a planning exercise can offer general context about design quantities, but it is not the trial's design justification and is not observed power. In this record, the missing numerical outcome analyses make that distinction especially important: planning assumptions cannot replace the effect estimate, event information, or uncertainty needed for interpretation.

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.

Several trial-specific limitations affect interpretation of the registry record. The most direct is the absence of numerical efficacy results. Although median RFS and a 95% confidence interval are specified, neither the estimate nor its bounds are reported. The record also does not report numerical results for the listed secondary survival outcomes. This prevents assessment of the observed outcome magnitude and its statistical precision.

The single-group design has no concurrent control group and no randomized treatment contrast. Allocation is listed as NA and masking as none. Any within-group outcome description cannot, by itself, establish a comparative effect or isolate the influence of radiation therapy from other factors. No adjusted analyses are reported in the registry record.

The record lists enrollment as 75, but does not say how many participants were treated, how many contributed to each outcome analysis, or why some might not have contributed. For the adverse-event categories, the at-risk count is 73, and the record does not explain how that relates to enrollment. There is no reported follow-up distribution, RFS event count, or number at risk over time, making the information supporting the survival estimates impossible to assess.

The stated RFS definition censors all deaths, but the rationale and implementation are not described. The registry also does not report detailed definitions for secondary outcomes, methods for missing data beyond the RFS censoring statement, confidence interval construction, analysis-population definitions, or sensitivity analyses. These omissions leave uncertainty about analytical choices and assumptions.

Safety information is limited to category counts and deaths. Event terms, timing, causes, and treatment relatedness are not reported, and no top serious-event terms are listed. Finally, the planning illustration is not the trial's own design justification. The registry record does not report a trial-specific sample-size rationale, and its planning assumptions do not resolve the lack of outcome estimates.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Radiation Therapy Alone for the Treatment of Stage 1 and 2 Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma — NCT04465162.
• Registry record last updated 2022-03-02; status last verified 2022-02.
• Results first posted 2022-03-02.
• 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 describes a completed phase 2, single-group study sponsored by M.D. Anderson Cancer Center, with enrollment listed as 75. The study evaluates radiation therapy alone for stage 1 and stage 2 MALT lymphoma. Treatment is described as QD 5 times weekly over 3.5-5 weeks. Allocation is NA and masking is none.

The primary outcome is median relapse-free survival in months, with a 95% confidence interval, through study completion, up to 10 years. Kaplan-Meier curves were estimated, and the definition states that all deaths are censored. Secondary outcomes are median progression-free survival, progression-free survival at 10 years, and overall survival at 10 years.

The registry does not report numerical efficacy estimates or analyses. Safety listings show 73 at risk for each adverse-event category, 0 affected by serious adverse events, 28 affected by other adverse events, and 11 deaths. Event details and the relationship between enrollment and the at-risk count are not reported.