Trial of Acupuncture for Radiation-Induced Xerostomia in Head and Neck Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Trial of Acupuncture for Radiation-Induced Xerostomia in Head and Neck Cancer (NCT02589938), a randomized na study. The primary outcome is Xerostomia Questionnaire Scores.

2. Clinical Question

The trial was randomized, parallel-group, and listed as triple-masked. Its listed enrollment was 258. The central clinical question is whether the measured symptom pattern differs across the three assigned approaches over follow-up. The available record identifies the outcome and schedule but does not report numerical results that would establish the direction or precision of any group differences. It therefore supports a description of the question the trial was designed to address, not a conclusion about the comparative outcome.

3. Trial Design

This was a randomized, parallel-group trial with three assigned groups: standard oral hygiene, standard oral hygiene plus true acupuncture, and standard oral hygiene plus sham acupuncture. The registry lists triple masking. It does not specify which participants, clinicians, assessors, or other personnel were masked, so the exact scope of masking is not reported in the registry record. The trial is listed as completed, with phase recorded as not applicable.

The registry lists enrollment of 258. That is the recorded enrollment, not a statement about how many participants contributed data at every follow-up assessment. The primary outcome population is described as intent to treat, with all data available at each time point considered and used. The number with observed outcome data at each assessment, and the handling of participants with incomplete follow-up, are not reported in the registry record.

All groups received standard oral hygiene patient teaching. The listed teaching topics include mouth rinses, lip balms, mild fluoride toothpaste, adequate oral hydration, and other standard advice. The intervention contrast is therefore not acupuncture against no care: true acupuncture and sham acupuncture were each paired with standard oral hygiene, while a separate group received standard oral hygiene alone. The record does not report the acupuncture schedule, treatment dose, or the details of the sham procedure.

The primary outcome schedule begins at baseline and includes assessments at 4, 8, 12, and 26 weeks post acupuncture. The registry also lists FACT-G total and the Acupuncture Expectancy Scale as secondary outcomes. Numerical results for these outcomes are not reported in the registry record. The dates recorded for trial start and primary completion are 2012-11-11 and 2022-07-29, respectively; these dates do not, on their own, describe the duration of treatment or follow-up for an individual participant.

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: 258 of 281 eligible screened participants enrolled and randomized into study. Reasons for the 23 which chose not to participate: 16 no reason given 5 Too busy 1 did not want randomization 1 distance.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intent to treat analysis. Considered and utilized all data available at each timepoint.

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 Xerostomia Questionnaire Scores, measured over Baseline to 4, 8, 12, 26 weeks post acupuncture.

The primary endpoint is the Xerostomia Questionnaire score, a self-reported measure of dryness symptoms. The questionnaire has eight items scored on an 11-point scale from 0 to 10. Four items ask about oral dryness while eating or chewing, and four ask about dryness when not eating or chewing. Item scores are summed and linearly transformed to a final score on a scale from 0 to 80. Higher scores represent more xerostomia.

The registry describes the questionnaire as validated in several cohorts and regarded as the gold-standard measure for xerostomia. A patient-reported symptom measure is relevant because the outcome of interest is a subjective experience of dryness in different contexts. General statistical context: using the same defined measure at baseline and follow-up makes it possible to describe how reported symptoms change over time and compare those patterns among randomized groups.

The stated primary measure is a least-squares mean with a 95% confidence interval. The assessment schedule is baseline to 4, 8, 12, and 26 weeks post acupuncture. The registry says the questionnaire is completed before randomization and at each follow-up time point. It does not report the actual least-squares means, confidence intervals, or between-group contrasts. The clinical meaning and precision of the observed score patterns therefore cannot be assessed from the numerical results in this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the primary endpoint as a least-squares mean for a continuous outcome, accompanied by a 95% confidence interval. It does not give the model formula, covariates, contrast definitions, or numerical estimates. The methods below explain the statistical concepts generally; they do not imply that any particular unreported method was used in this trial.

What does a least-squares mean represent?

General statistical context: a least-squares mean, also called a model-based mean, is an estimate derived from a statistical model rather than simply the arithmetic average of all observed scores. Depending on the model, it can represent a mean adjusted for specified factors or estimated at a defined combination of factors. It is important to know the model and the adjustment variables to interpret it fully. Those details are not reported in the registry record. The label alone does not show which factors were included or how repeated assessments were handled.

For this trial, the outcome is a continuous questionnaire score from 0 to 80, with higher scores indicating more xerostomia. A model-based summary could be used to describe scores at specified follow-up times or changes from baseline. The registry identifies a baseline-to-follow-up schedule but does not state the exact estimand, such as whether the reported least-squares means represent follow-up scores, changes, or another model-defined quantity. Numerical estimates are not reported in the registry record.

What does a 95% confidence interval communicate?

General statistical context: a confidence interval expresses the uncertainty associated with an estimate under the assumptions of the method used. It provides a range of values compatible with the observed data and model at the stated confidence level. It is not a guarantee that the true value lies within the particular interval, and its width depends on factors such as variability and the amount of informative data. Because no interval limits are reported for this endpoint, the precision of the trial’s estimated scores or contrasts cannot be assessed from the registry record.

A confidence interval for each group mean is not necessarily the same as a confidence interval for a difference between groups. The latter directly addresses a comparative question. The registry record does not report the numerical between-group contrasts or their intervals. It is therefore not possible to infer comparative precision from the description of the summary measure alone.

Why does the repeated schedule matter?

General statistical context: when a continuous outcome is measured repeatedly in the same participant, observations from that participant are usually related rather than independent. An analysis may account for that within-person correlation, but the appropriate approach depends on the design and the analysis plan. The record lists assessments at baseline and at 4, 8, 12, and 26 weeks post acupuncture, but does not report how correlation across assessments was modeled. It also does not state whether the main comparison was at a single time point, across the full trajectory, or through another summary.

Assessing scores at multiple times can describe whether changes are sustained or vary over follow-up. General statistical context: repeated measurements can add information, but they also raise questions about the primary time point, the handling of incomplete measurements, and whether comparisons across times were planned or exploratory. The registry record does not report these analysis details. It identifies the schedule, not a complete statistical analysis plan.

What role does randomization play?

General statistical context: random assignment is intended to make treatment groups comparable on average at the time of assignment, including for factors that may not have been measured. It does not ensure that every group will be identical, and it does not eliminate uncertainty from outcome variability, missing data, or measurement. The registry labels the allocation as randomized and lists three groups. The sequence-generation and allocation-concealment procedures are not reported in the registry record.

The parallel design means the listed groups are separate assigned groups rather than a stated crossover sequence. The registry also labels masking as triple, but does not identify the people masked or describe how masking was maintained. Those details matter for judging possible influences on reported symptoms, treatment delivery, and outcome assessment. They are not reported in the registry record.

How should planning illustrations be understood?

General statistical context: a sample-size illustration estimates how many participants per arm a future study might need under specified assumptions about the effect to detect, significance level, allocation, and statistical model. It is a planning exercise, not an observed result and not a measure of the probability that the completed trial detected an effect. The record describes illustrations based on fractions of an observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It specifies participants per arm for non-time-to-event outcomes. These assumptions do not establish the design rationale used for this trial, and the registry does not report a trial-specific sample-size justification.

Because the numerical primary outcome estimates are not reported, the comparative effect and its precision cannot be independently assessed from this record. Any interpretation of the model, interval, or planning assumptions should remain separate from claims about what the trial found.

10. Multiplicity, Missing Data and Analysis Populations

The primary endpoint is assessed at baseline and at 4, 8, 12, and 26 weeks post acupuncture. Three randomized groups create more than one possible pairwise comparison, and multiple assessment times can also create multiple opportunities for statistical testing. The registry record does not report a multiplicity strategy, such as a designated primary contrast, adjustment procedure, or hierarchy for interpreting tests. It is therefore not possible to determine from the record how the risk of false-positive findings across multiple comparisons was addressed.

The registry lists two secondary outcomes: FACT-G total and the Acupuncture Expectancy Scale. It does not report numerical results for these measures or describe how their analyses were prioritized relative to the primary endpoint. The relationship among the listed outcomes and the analysis plan is not reported in the registry record. The record’s designation of the Xerostomia Questionnaire as the primary outcome does not, by itself, disclose how all other tests were handled.

The analysis population is described as intent to treat, with all data available at each time point considered and used. This conveys that available observations were included in the stated analysis population approach. It does not explain why data may have been missing, how much was missing at each time, whether missingness differed by group, or whether imputation or other methods were used. Those details are not reported in the registry record.

General statistical context: missing outcome data can reduce precision and may bias estimates if the reasons for missingness are related to symptoms or assigned group. The direction and size of any such effect cannot be determined without information about missingness and analysis assumptions. No specific missing-data mechanism or sensitivity analysis is reported in the registry record. The record also does not describe a statistical analysis plan in enough detail to assess prespecification of contrasts, multiplicity handling, or robustness checks.

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 adverse-event record lists 0 participants with serious adverse events among 86 at risk in each group. Deaths are listed separately: 1 in the standard oral hygiene group, 0 in the standard oral hygiene plus true acupuncture group, and 1 in the standard oral hygiene plus sham acupuncture group. Other adverse events are listed as 0, 3, and 3, respectively, in those same groups.

These entries are counts, not comparative risk estimates. No rates or statistical comparisons are reported in the registry record, and none should be inferred by calculating them from the counts. The record does not provide event descriptions for the other adverse events, timing, relatedness to treatment, or the period over which participants were monitored for these entries. The serious adverse event terms list is empty, so specific serious-event categories are not reported.

General statistical context: safety counts are most informative when considered alongside definitions, observation periods, event severity, and participant exposure. A zero count in a registry entry means no events were recorded in that entry; it does not establish that an event is impossible or that groups have identical safety profiles. The death counts are not included in the serious adverse event affected counts as presented, so they should be read as a separate recorded outcome. These limited entries do not replace the missing primary symptom results.

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

The record establishes that a randomized, three-arm trial was conducted to examine acupuncture for radiation-induced xerostomia in people with head and neck cancer. It identifies the intervention groups, the primary questionnaire, and the follow-up schedule. It also records selected adverse-event counts and two secondary outcomes. These details describe the study question and some aspects of its design.

The record does not report the numerical least-squares means, 95% confidence intervals, or comparative estimates for the primary endpoint. It therefore does not show how questionnaire scores changed in each group, whether the groups differed, or how precise any estimated differences were. The same limitation applies to the listed secondary outcomes, whose numerical findings are not reported in the registry record. No conclusion about comparative symptom effects can be drawn from the outcome descriptions alone.

The record’s statement that the primary analysis was intent to treat and used all data available at each time point is useful, but incomplete as a description of analysis conduct. It does not reveal the number of observed scores at each assessment, how missingness was handled, which statistical model was used, or which contrasts were tested. Those omissions limit interpretation of both the method and any potential result.

The safety entries show the recorded counts for serious events, deaths, and other adverse events. They do not supply event details or a basis for comparing rates. General statistical context: results from a clinical trial require both an estimate and an assessment of uncertainty; design labels and outcome definitions cannot substitute for those results. The appropriate reading is therefore that the registry record documents a completed randomized study and its intended measurement framework, while its posted numerical primary outcome findings are not reported in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically notable for setting up a three-group comparison that separates true acupuncture, sham acupuncture, and standard oral hygiene alone. Such a structure can address different contrasts: the true-acupuncture group versus standard care alone, the true-acupuncture group versus sham, and sham versus standard care alone. The registry record lists these groups, but does not report the numerical results or identify which contrast was the principal statistical comparison.

The primary measure is a patient-reported scale with a defined range and direction, assessed repeatedly from baseline through follow-up. This creates a clear link between the measured score and the symptom under study. General statistical context: repeated measurement can help describe a symptom’s trajectory, but it also makes the definition of the primary time point and the method for handling within-participant correlation important. Those analysis choices are not reported in the registry record.

The registry identifies a least-squares mean and 95% confidence interval, statistical summaries that can communicate model-based estimates and uncertainty. However, the numerical estimates are not reported. This is an important distinction: the existence of a specified statistical summary does not allow readers to assess the magnitude, direction, or precision of an effect when its values are absent.

The record also lists an intent-to-treat analysis using available data at each time point and records selected safety counts. These details offer some context, but do not answer questions about incomplete follow-up, model specification, or safety-event definitions and observation periods. The study is therefore useful as a case in how a registry can document a randomized design and outcome framework while leaving key information needed for statistical interpretation unreported.

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 main limitation for interpreting this trial from the registry record is the absence of numerical primary outcome results. Although the endpoint, summary measure, and follow-up schedule are specified, the least-squares means, 95% confidence intervals, and between-group contrasts are not reported. This prevents assessment of the direction, magnitude, and precision of the symptom findings. Numerical results for the secondary outcomes are also not reported.

The statistical analysis is described only briefly. The record identifies an intent-to-treat population and says all data available at each time point were considered and used, but does not report the model, covariates, contrast definitions, or treatment of repeated measurements. It does not describe the amount or pattern of missing data, imputation, sensitivity analyses, or multiplicity procedures. As a result, the robustness of any potential comparisons cannot be evaluated from the registry record.

Important intervention details are also not reported. The record names true and sham acupuncture but does not describe the procedures or treatment schedule. It lists triple masking without specifying who was masked or how masking was maintained. These omissions limit assessment of how the intervention contrast was implemented and the extent to which expectations or treatment delivery could influence self-reported scores.

The safety entries lack event descriptions for other adverse events and do not state the observation period or relatedness assessments. The registry lists enrollment of 258, but does not report the number with outcome data at each time point. These limitations concern what can be learned from the registry record; they do not establish that the omitted details were absent from other trial materials.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Trial of Acupuncture for Radiation-Induced Xerostomia in Head and Neck Cancer — NCT02589938.
• Registry record last updated 2026-02-27; status last verified 2026-02.
• Results first posted 2024-09-19.
• 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, randomized, triple-masked, parallel-group trial of acupuncture for radiation-induced xerostomia in people with head and neck cancer. It lists enrollment of 258 and three groups: standard oral hygiene alone, standard oral hygiene plus true acupuncture, and standard oral hygiene plus sham acupuncture. The trial phase is recorded as not applicable.

The primary endpoint is the Xerostomia Questionnaire score, ranging from 0 to 80, with higher scores indicating more xerostomia. The listed assessments are baseline and 4, 8, 12, and 26 weeks post acupuncture. The analysis population is described as intent to treat, using all data available at each time point.

FACT-G total and the Acupuncture Expectancy Scale are listed as secondary outcomes. Numerical primary and secondary outcome results, detailed analysis methods, and missing-data procedures are not reported in the registry record. The adverse-event entries list no serious adverse events among participants at risk in any group, with deaths and other adverse events recorded separately.