Low-Level Laser Therapy for Prevention of Oral Mucositis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Low-Level Laser Therapy for Prevention of Oral Mucositis (NCT02723604), a na na study. The primary outcome is Number of Participants With Severe (Common Terminology Criteria for Adverse Events Version 4.0 [CTCAE v. 4.0] Grade 3-5 Oral Mucositis in Patients Treated to a Cumulative Radiation Dose of at Least 5000 cGy.

2. Clinical Question

The study’s stated purpose was to examine prophylactic low-level laser therapy in patients receiving combined chemotherapy and radiation for head and neck cancer. Its primary question concerns the occurrence of severe oral mucositis during and after that treatment period. Secondary outcomes covered oral mucositis-related quality of life, duration of mucositis, any-grade mucositis in the specified radiation-dose population, and other treatment-related symptoms or effects.

Because the design has one treatment group and no concurrent comparator, the primary outcome can describe the observed experience in that group, if reported. It cannot by itself establish how that experience compares with what would have happened under a different care strategy. The registry record does not report a primary-outcome result, so the occurrence of severe oral mucositis in the defined population cannot be summarized from the posted results.

3. Trial Design

The registry describes a completed, prospective, single-group study of low-level laser therapy for prevention of oral mucositis. Its official title calls it a Phase II trial, while the registry phase field is recorded as NA. The sponsor was Barbara Ann Karmanos Cancer Institute. The record lists enrollment as 25 and gives a study start of 2016-03 and primary completion of 2017-08-02.

Participants were to receive prophylactic low-level laser therapy in addition to standard-of-care measures for oral mucositis or other therapy toxicity. The arm description states that chemotherapy and radiation dosing, scheduling, modality, technique, and any required adjustments would not be influenced by the intervention. Further details of treatment delivery, eligibility criteria, and adherence are not reported in the registry record.

Allocation is recorded as NA, masking as NONE, and the model as SINGLE GROUP. There is no parallel control arm in the registry description. The design is therefore suited to describing outcomes among participants receiving the intervention, but it does not supply a randomized comparison for estimating a difference attributable to the intervention. Historical or external comparisons would require information and assumptions not reported in the registry record.

The primary outcome concerned severe oral mucositis among patients who reached the specified cumulative radiation dose. Its timeframe extended from the beginning of therapy to 3 months after completion. The registry lists 20 outcome measures, including the primary and secondary measures, but does not provide a primary-outcome result or analysis details. The record status is COMPLETED; that status alone does not establish that every planned outcome was measured or reported.

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:

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 Number of Participants With Severe (Common Terminology Criteria for Adverse Events Version 4.0 [CTCAE v. 4.0] Grade 3-5 Oral Mucositis in Patients Treated to a Cumulative Radiation Dose of at Least 5000 cGy, measured over From beginning of therapy up to 3 months after completion of therapy.

The primary endpoint is the number of participants with severe oral mucositis, defined as Common Terminology Criteria for Adverse Events version 4.0 grade 3–5, among patients treated to a cumulative radiation dose of at least 5000 cGy. The stated timeframe is from the beginning of therapy up to 3 months after completion. It is a count endpoint: it records how many participants in the defined outcome population experienced the specified severity category during that period.

Severity grading distinguishes more substantial toxicity from less severe manifestations. In general, this kind of endpoint can help characterize the burden of an adverse effect that the study aims to prevent. The registry also lists an outcome for any-grade oral mucositis in the specified radiation-dose population, which addresses a broader severity range than the primary endpoint.

A count is most interpretable alongside the number of participants assessed for the endpoint and a clear account of missing observations. Those details, together with the primary count result, are not reported in the registry record. The enrollment figure should not be treated as the endpoint denominator: the primary outcome is restricted by the cumulative radiation-dose criterion, and the registry does not state how many participants met that criterion or had evaluable outcome data.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a count endpoint describe?

The primary measure is a count of participants meeting a defined outcome: severe oral mucositis at CTCAE v. 4.0 grade 3–5. A count is a direct way to report how many people had an event, but it needs a defined population and observation period to be interpretable. This endpoint specifies both a cumulative radiation-dose criterion and a timeframe from therapy start through 3 months after completion. The number assessed under those criteria is not reported in the registry record.

In general, a count can be paired with its denominator to describe the proportion of assessed participants with the event. That proportion is not the same as a treatment effect. A comparative treatment effect requires a suitable contrast, such as outcomes in an intervention group compared with outcomes in a control group. This study is listed as single-group, with no concurrent comparator, so the design does not provide that contrast.

How should uncertainty be considered?

In general, a confidence interval communicates the precision of an estimate by describing a range of values compatible with the observed data under a specified method. Wider intervals indicate less precision, while narrower intervals indicate greater precision. The primary count and its denominator are not reported, and the method for estimating uncertainty is not reported in the registry record. No primary-endpoint confidence interval is available to interpret.

Statistical tests and models depend on the question and design. For a single-group binary outcome, an analysis could describe the event frequency and its uncertainty. For a comparison, the analysis would also need to account for the structure of the groups and the planned contrast. These are general principles, not a description of analyses performed in this study; the statistical analysis plan is not reported in the registry record.

What do the planning assumptions mean?

The registry’s sample-size planning description refers to a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. It also distinguishes total events for time-to-event planning from participants per arm for other calculations. These are planning assumptions, not observed trial results. The record does not report numerical sample-size illustrations in the information available for interpretation, and these assumptions do not establish that the single-group study was designed around a two-arm comparison.

A planning calculation is not observed power. It describes a hypothetical design under specified assumptions; it does not measure whether an observed result is reliable or whether an effect is present. In particular, the single-group registry design and absence of a reported primary result mean there is no posted primary effect estimate on which to base a treatment comparison. The protocol’s sample-size justification is not reported in the registry record.

What analysis details are absent?

The registry does not report the statistical methods for the primary endpoint, a prespecified analysis population, handling of missing outcome data, or any interim analyses. It also does not report the number of participants who reached the radiation-dose threshold or were evaluable for the endpoint. Without those details, it is not possible to assess whether the analysis followed a prespecified plan, how incomplete follow-up was handled, or how the target population was represented in the result.

Generally, a clear analysis should state how outcomes are defined, which participants are included, how missing observations are treated, and how uncertainty is calculated. With multiple outcomes, it is also useful to explain whether the analyses are confirmatory or descriptive and how multiplicity is handled. These methodological details are not reported in the registry record. The available registry description therefore supports an account of the design and planned outcome definitions, but not a reconstruction of the statistical analysis.

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("Experimental: Low Level Laser Therapy")
n      <- c(23)
events <- c(15)
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  Experimental: Low Level Laser Therapy  23  15  65.2  42.7  83.6  44.9  81.2  44.7  81.2

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 20 outcome measures. Alongside severe oral mucositis, the secondary outcomes include change in oral mucositis-related quality of life, mucositis duration, any-grade mucositis for patients treated to the specified radiation dose, dysgeusia, dysphagia, pain, radiodermatitis, and trismus. The registry record does not report a multiplicity plan, such as whether one outcome was treated as primary for formal inference or how interpretation would account for examining multiple outcomes.

Multiplicity matters in general because examining several outcomes can increase the chance of finding an apparently notable result by chance. The appropriate approach depends on the study’s aims and analysis plan. Neither that plan nor results for the listed outcomes are reported in the registry record, so the role of the secondary measures in confirmatory or exploratory interpretation is unclear.

Missing-data methods and analysis populations are also not reported. The primary outcome is limited to participants treated to a cumulative radiation dose of at least 5000 cGy, but the number reaching that threshold and the number with an evaluable mucositis assessment are not given. The overall enrollment figure does not establish either number. The record does not explain whether incomplete follow-up, missed assessments, or other unavailable observations occurred, or how they would be handled.

These omissions limit assessment of selection and attrition in the primary analysis. They also make it impossible to determine whether the primary result, if available elsewhere, represents all enrolled participants or a defined subset. The registry record lists no analysis details for resolving these questions.

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.

Most frequent non-serious adverse event terms

The registry safety summary reports 0 serious adverse events among 23 participants at risk. It also records 23 participants at risk and 23 with other adverse events, with 0 deaths. The record does not list serious adverse event terms. These figures describe the safety summary as posted; they do not provide a complete account of event type, severity, timing, or attribution.

The serious and other adverse-event categories are separate from the primary mucositis endpoint. In particular, the figure for other adverse events cannot be read as a count of participants with mucositis, and it does not indicate that every recorded event was caused by the intervention. The registry record does not give event-specific details or an attribution assessment.

The safety summary uses 23 participants at risk, whereas overall enrollment is recorded as 25. The registry does not explain this difference, so it should not be interpreted as evidence about why participants were or were not included in the safety summary. These descriptive counts also do not establish comparative safety because the study has no concurrent control arm.

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

The record documents a prospective, single-group investigation of prophylactic low-level laser therapy added to standard-of-care measures during chemotherapy and radiation for head and neck cancer. It defines severe oral mucositis as the primary outcome and sets an observation period extending from therapy start to 3 months after completion. This makes the clinical focus and outcome definition identifiable from the registry description.

However, the primary outcome result is not reported in the registry record. There is no posted count of participants with severe oral mucositis, no corresponding denominator, and no uncertainty interval to show precision. The safety summary supplies some adverse-event counts, but these do not replace the primary endpoint or answer the primary question.

The single-group design also limits what any observed count could establish. A description of outcomes among treated participants is not a direct estimate of what would differ under another care strategy. Without a concurrent comparison group, the record cannot separate outcomes associated with the intervention from outcomes that could occur under standard care or from other influences. No comparative estimate is reported.

Accordingly, the registry information supports describing the study’s purpose, design, endpoint, and reported safety counts. It does not support a conclusion about whether the intervention changes the risk of severe oral mucositis, nor does it establish the size or precision of any such change. The absence of a result in the registry record should be understood as missing reporting in that record, not as evidence that the outcome did or did not occur.

14. Why This Trial Matters Statistically

This trial is statistically notable for the difference between a clearly specified clinical question and the limited inferential structure of a single-group design. The registry defines a severe mucositis outcome, identifies a radiation-dose condition for the primary population, and gives a follow-up window. Those details are important because outcome definitions and observation periods determine what a count represents.

At the same time, a well-defined endpoint does not by itself make a comparative treatment effect estimable. In a single-group study, an observed count can describe the treated group, but there is no internal control group to show the outcome under an alternative strategy. That distinction matters when interpreting any claim about prevention or reduction: the study’s stated purpose is not itself evidence of a comparative effect.

The record also illustrates why denominators and missing-data descriptions are central to clinical statistics. Overall enrollment is recorded, while the primary endpoint applies to a threshold-defined population. Without the number reaching that threshold and the number assessed, the primary outcome’s frequency and precision cannot be evaluated. A count without its relevant analysis population would be incomplete context.

Finally, the registry lists a range of secondary outcomes but does not report their results or the approach to multiplicity. Transparent outcome reporting and analysis plans help readers distinguish a prespecified primary inference from broader descriptive exploration. Here, the registry record makes the planned scope visible but does not provide enough results or methods to evaluate those analyses.

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 main limitation for interpretation is that the registry record does not report the primary endpoint result, its denominator, or an uncertainty estimate. This prevents assessment of the observed frequency and precision of severe oral mucositis in the specified population. The record also does not state how many participants reached the cumulative radiation-dose threshold of at least 5000 cGy.

The design is single-group and has no concurrent control arm. Consequently, the registry description does not support a randomized or otherwise direct within-trial comparison with standard care alone. The masking field is NONE, and details about outcome assessment procedures are not reported in the registry record.

Information about eligibility criteria, intervention delivery, adherence, and the reasons for any differences between overall enrollment and the safety summary is not reported in the registry record. The analysis population, missing-data handling, statistical methods, and multiplicity approach are also not reported. These gaps prevent evaluation of how participants were selected for the primary analysis, how incomplete observations were handled, and how the listed outcomes were intended to be interpreted.

The safety summary is limited to aggregate counts and does not include serious-event terms or details about event timing, severity, or attribution. The registry’s COMPLETED status does not resolve these reporting limitations or supply the missing outcome estimates.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Low-Level Laser Therapy for Prevention of Oral Mucositis — NCT02723604.
• Registry record last updated 2023-02-27; status last verified 2023-02.
• Results first posted 2023-02-27.
• 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

NCT02723604 is a completed, prospective, single-group study of low-level laser therapy for prevention of oral mucositis in patients receiving chemotherapy and radiation for head and neck cancer. The official title describes it as Phase II, although the registry phase field is NA. The sponsor is Barbara Ann Karmanos Cancer Institute, and enrollment is recorded as 25.

The primary endpoint was the number of participants with CTCAE v. 4.0 grade 3–5 oral mucositis among those treated to a cumulative radiation dose of at least 5000 cGy, from therapy start through 3 months after completion. The registry record does not report the primary result or its analysis details. Its safety summary records 0 serious adverse events among 23 at risk, 23 participants with other adverse events, and 0 deaths. No concurrent comparator is listed.