An Initial Study of Lithium in Patients With Medullary Thyroid Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for An Initial Study of Lithium in Patients With Medullary Thyroid Cancer (NCT00582712), a na phase 2 study. The primary outcome is Tumor Response Rate Measured by the Response Evaluation Criteria in Solid Tumors (RECIST).

2. Clinical Question

In statistical terms, the intended question was descriptive: what tumor response was observed in the treated group? Without a comparison group, the study could not estimate a contrast between lithium carbonate and another treatment or control condition. Even if response results had been recorded, a single-group result would describe outcomes in this study population; it would not by itself distinguish an intervention effect from other explanations for observed change.

The registry record does not provide a response count, response rate, estimate of uncertainty, or details of an analysis population. Consequently, the primary question remains unanswered by the posted results. The reported enrollment is not a substitute for endpoint data: it indicates the listed study enrollment, not how many participants had an evaluable tumor assessment.

3. Trial Design

The registry identifies this as a phase 2 study of lithium carbonate in medullary thyroid cancer. It lists one arm, Lithium Capsules, with lithium carbonate as the intervention. The study model is single group, allocation is NA, and masking is none. These features mean the registry does not describe randomized assignment, a masking procedure, or a concurrent comparator arm.

The listed enrollment is 5. The study start is recorded as 2008-01, and primary completion as 2009-05. Its current status is terminated. The reason for termination, whether the planned recruitment was completed, and the timing or circumstances of termination are not reported in the registry record. The status alone does not establish why the study ended.

The primary outcome is tumor response measured by the Response Evaluation Criteria in Solid Tumors (RECIST), with a timeframe of 1 year. The registry lists one outcome measure, but its population description states: “No data was ever analyzed, resulted, or published on this study.” No endpoint results or analyses are listed. Details such as the planned assessment schedule, imaging procedures, response confirmation rules, or handling of participants without an assessment are not reported in the registry record.

Because the study has no listed control group, any interpretable outcome would have been a description of the treated group rather than a randomized treatment contrast. Allocation, masking, and model should therefore be read together: the design record describes a single-group study, not a comparative trial. The protocol, detailed statistical analysis plan, sample-size justification, and reason for termination 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: No data was ever analyzed, resulted, or published on this 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: This study enrolled participants with Medullary Thyroid Cancer (MTC).

6. Primary Endpoint

The registry lists the primary outcome as Tumor Response Rate Measured by the Response Evaluation Criteria in Solid Tumors (RECIST), measured over 1 year.

The primary endpoint is tumor response measured by RECIST over 1 year. RECIST is a standardized framework for classifying changes in tumor measurements, allowing response to be assessed using consistent criteria rather than an informal judgment. In general, standardized response criteria can make assessments more reproducible and help researchers define what counts as a response before looking at outcomes. The particular RECIST version, measurement rules, and confirmation procedures are not reported in the registry record.

The stated objective was to evaluate the tumor response rate among patients with medullary thyroid cancer treated with lithium carbonate. A response rate ordinarily describes the proportion of an analyzed group meeting the prespecified response definition. Interpreting such a rate requires knowing both the response classification and the number of participants included in the endpoint analysis. The registry record gives neither: its outcome description says no data were analyzed, resulted, or published.

The listed timeframe is 1 year, but further details about when or how often tumor assessments were intended to occur are not reported in the registry record. There is no reported response estimate, denominator for an endpoint analysis, or confidence interval. Thus, the endpoint identifies the clinical outcome the study aimed to assess, but the posted record does not establish what tumor responses were observed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes the trial as single group, with allocation NA and masking none. It lists one outcome measure and no analyses. The record therefore identifies an endpoint and a study structure, but does not provide an analysis of tumor response. The statistical concepts below are general explanations of how such an endpoint might be interpreted; they are not claims about analyses performed in this study.

What would a response rate describe?

In general, a response rate is a proportion: the number of participants meeting a defined response criterion relative to the number included in the endpoint analysis. The definition of response should follow the prespecified criteria, and the analysis denominator should include only participants meeting the stated analysis rules. Enrollment, treatment receipt, follow-up, and endpoint evaluability are not necessarily interchangeable. The registry record does not report a response count, an analysis denominator, or rules for participants whose tumor status could not be assessed. No response rate can therefore be reconstructed.

Why is uncertainty important?

In general, a point estimate alone does not show how much uncertainty surrounds an observed response rate. A confidence interval expresses a range of values compatible with the data under the method’s assumptions. With limited information, that interval cannot be calculated or interpreted. Here, there is no reported endpoint estimate or analysis dataset, so no confidence interval for tumor response is available. The registry record also does not report a statistical test or a prespecified hypothesis for the endpoint.

What does a single-group design allow?

In general, a single-group study can describe outcomes observed among participants in that group. It does not supply a concurrent control outcome against which to estimate a randomized treatment contrast. A response observed after treatment would not, by itself, establish that the intervention caused the response. This distinction is especially important when interpreting an endpoint as evidence about treatment effect rather than as a description of study observations. In this record, there is no response result to describe in the first place.

The lack of masking is also part of the design description, but the registry does not report how tumor assessments were conducted or whether independent review was used. In general, standardized assessment criteria can reduce ambiguity, while details about assessment procedures help readers judge the potential for measurement differences. Such procedures are not reported in the registry record and should not be assumed.

What can be inferred from the planning information?

In general, sample-size calculations depend on assumptions about the outcome, the effect to be detected, the analysis method, and the desired error rates. Planning calculations are illustrations of design requirements under stated assumptions; they are not observed results or evidence that a study had a particular power after completion. The registry record does not report a sample-size justification or the assumptions used for the original study design.

The planning assumptions associated with posted sample-size illustrations describe a two-arm, equal-allocation calculation based on a fraction of an observed effect, with a two-sided significance level of 0.05 and a normal approximation. This study, by contrast, is listed as single group, and no observed primary endpoint effect is reported. Those assumptions therefore do not establish the design rationale or operating characteristics of this trial. A planning illustration must not be read as observed power, and the absent response results prevent an effect-based planning interpretation for this study.

How should adverse-event fields be interpreted?

In general, adverse-event summaries may report the number at risk, the number with events, and selected event terms. These figures answer different questions: affected participants are not the same as event counts, and a listed term does not necessarily reveal whether events occurred in the same participant or how events were attributed. Interpretation also depends on definitions, follow-up, coding, and completeness of reporting. The record lists group-level counts and several terms with percentages, but it does not report detailed event narratives, attribution, or the death count.

The registry records 5 at risk and 4 affected for serious adverse events, and 5 at risk and 0 affected for other adverse events. It lists Death at 60.0%, Grade 3 fatigue at 20.0%, Grade 3 speech impairment at 20.0%, and Grade 2 dizziness (vertigo) at 20.0%. These entries are not sufficient to infer causality, timing, severity beyond the terms shown, or a comprehensive safety profile. The record does not state how these safety data were analyzed.

Finally, the record does not provide enough information to assess the statistical methods actually used for tumor response. It lists no analyses and states that no outcome data were analyzed, resulted, or published. Details of the protocol and statistical analysis plan, including any interim analyses or multiplicity procedures, are not reported in the registry record. General statistical principles should not be mistaken for methods documented as having been used in this study.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, the RECIST tumor-response endpoint, and reports no analyses. It does not provide an endpoint result or a statistical analysis plan. Whether the protocol included additional planned outcomes, multiple time points, subgroup analyses, or several hypotheses is not reported in the registry record. The number of listed outcome measures does not establish the full set of analyses that may have been planned.

Multiplicity concerns arise in general when several outcomes, time points, subgroups, or statistical tests are examined. Repeated testing can increase the chance of a chance finding, so a prespecified analysis plan may describe how such testing is handled. No multiplicity procedure is reported in the registry record. Since no primary endpoint analysis is reported, there is no basis to assess whether multiplicity affected an efficacy conclusion.

Missing-data methods are also not reported. The record does not state how participants without an evaluable tumor assessment would have been handled, whether missing assessments occurred, or whether any sensitivity analyses were planned or performed. The listed enrollment of 5 does not identify the endpoint analysis population or show whether all enrolled participants had follow-up.

Analysis populations—such as all enrolled participants, those who started treatment, or those with evaluable assessments—are not defined in the registry record. No data were analyzed, resulted, or published according to the primary outcome description. Accordingly, neither the handling of missing outcomes nor the population used for an efficacy estimate can be evaluated.

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.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: death (60.0%), grade 3 fatigue (20.0%), grade 3 speech impairment (20.0%), grade 2 dizziness (vertigo) (20.0%).

The registry lists 5 participants at risk for serious adverse events in the Lithium Capsules group, with 4 affected. For other adverse events, it lists 5 at risk and 0 affected. These categories are reported separately and should not be combined into a new total. The record does not explain the event definitions, surveillance procedures, or duration of safety follow-up.

The listed serious-event terms include Death at 60.0%, Grade 3 fatigue at 20.0%, Grade 3 speech impairment at 20.0%, and Grade 2 dizziness (vertigo) at 20.0%. The registry also lists the death count as not reported. The percentage attached to the Death term should therefore be read as a registry entry, not converted into a count or treated as a complete account of deaths.

These fields do not establish whether events were caused by lithium carbonate, when they occurred, whether multiple terms applied to the same participant, or whether reporting was complete. The registry does not provide narratives or an explanatory safety analysis. The figures are descriptive entries in the record and do not support a broader comparison or causal conclusion.

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

The record establishes that a phase 2, single-group study of lithium carbonate in medullary thyroid cancer was registered, with an intended primary outcome of RECIST-measured tumor response over 1 year. It lists enrollment of 5, a study status of terminated, and selected adverse-event fields. These registry entries describe the registered study and its posted record.

The record does not establish the observed tumor response. The primary outcome description explicitly says that no data were analyzed, resulted, or published. There is no response rate, response count, confidence interval, or statistical test to interpret. The enrollment figure cannot fill that gap because the endpoint analysis population and evaluability are not reported.

Nor does the study design provide a randomized control comparison. Even if an outcome estimate were available, a single-group result would describe the group rather than isolate a treatment effect against a concurrent comparator. In this record, there is no efficacy estimate to interpret in either a descriptive or comparative way.

The termination status does not explain why the study ended. No reason for termination, sample-size justification, detailed protocol, or statistical analysis plan is reported in the registry record. The listed safety entries also do not establish causation or provide a complete safety profile. As a result, the record cannot support conclusions about benefit, lack of benefit, or the cause of reported adverse events.

The most defensible interpretation is therefore limited: the registry documents an intended response assessment and selected safety information, but it supplies no analyzed primary outcome results. Absence of a reported result is not itself evidence that the endpoint was positive or negative.

13. Why This Trial Matters Statistically

This study illustrates the distinction between registering a clinical question and reporting analyzable outcome evidence. The record identifies a population, intervention, single-group structure, and a standardized tumor-response endpoint. Those details help readers understand what the study set out to assess. But without analyzed endpoint data, the stated question cannot be answered from the record.

It also demonstrates why enrollment and endpoint results are not interchangeable. The listed enrollment is 5, but the record does not report how many participants had an evaluable response assessment or entered an endpoint analysis. Statistical interpretation depends on the actual outcome data and the population analyzed, not simply on the number recorded as enrolled.

The design description matters as well. A single-group study can provide descriptive information, whereas a randomized comparison is designed to estimate a contrast between assigned groups. The registry lists no comparator, so a treatment effect relative to a control cannot be derived. This remains true even if a response estimate were available; in this record, no such estimate is reported.

Finally, the study’s terminated status and the presence of selected adverse-event fields do not replace a transparent account of endpoint analysis, missing data, or safety methods. The reason for termination and the analysis procedures are not reported. For statistical readers, the central lesson is to separate what the record documents—design, intended measurement, status, and selected safety entries—from what it does not document: an analyzed tumor-response outcome.

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 principal limitation is the absence of primary outcome results. The registry states that no data were analyzed, resulted, or published, so tumor response cannot be estimated. No response count, denominator, or uncertainty interval is reported.

The record also gives limited information about who contributed to the intended endpoint. Enrollment is listed as 5, but treatment receipt, follow-up, evaluability, and the analysis population are not reported. There is no description of missing tumor assessments or how they would have been handled.

The single-group design has no listed comparator, and the record reports no masking. Consequently, the study does not provide a randomized contrast. The registry does not report assessment procedures, the RECIST version, confirmation requirements, or the detailed schedule for tumor evaluation beyond the 1 year timeframe.

The study is marked terminated, but the reason for termination is not reported in the registry record. A protocol, original sample-size justification, detailed statistical analysis plan, interim-analysis information, and multiplicity procedures are also not reported. Their absence prevents assessment of whether the posted endpoint and safety fields reflect all planned measurements or analyses.

Safety information is limited to selected registry entries. The death count is not reported, and event timing, attribution, narratives, and completeness are not described. These limitations mean that neither the missing efficacy results nor the selected adverse-event fields can support broad conclusions about treatment effects or safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: An Initial Study of Lithium in Patients With Medullary Thyroid Cancer — NCT00582712.
• Registry record last updated 2019-12-09; status last verified 2016-10.
• Results first posted 2016-12-12.
• 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 a phase 2, single-group study of lithium carbonate in patients with medullary thyroid cancer. It lists enrollment of 5, no masking, and a terminated status. The primary endpoint was tumor response measured by RECIST over 1 year.

The primary outcome description states that no data were analyzed, resulted, or published. No tumor-response estimate or analysis is reported. The record lists 5 at risk and 4 affected for serious adverse events, and 5 at risk and 0 affected for other adverse events. It also lists selected event terms and percentages, while the death count is not reported.

The registry does not report a comparator, reason for termination, analysis population, missing-data approach, sample-size justification, or detailed statistical analysis plan. The record documents the intended question and selected design and safety details, but does not provide an analyzed efficacy result.