Modified Dakin's Solution in Reducing Radiation-Induced Dermatitis in Patients With Head and Neck Cancer Undergoing Radiation Therapy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Modified Dakin's Solution in Reducing Radiation-Induced Dermatitis in Patients With Head and Neck Cancer Undergoing Radiation Therapy (NCT02369835), a randomized phase 3 study. The primary outcome is Radiation Dermatitis.

2. Clinical Question

The timeframe begins at the first radiation treatment and extends up to 10 weeks after radiation treatment completion. The record notes that a more precise timeframe cannot be stated. Radiation treatment was described as regulatory medical care determined according to the patient's needs and the radiation oncologist's judgment; its dose and duration were not explicitly defined in the study description. Two secondary outcomes are listed: time to Grade E radiation dermatitis and pain associated with radiation dermatitis.

3. Trial Design

The registry identifies NCT02369835 as a randomized phase 3 study of topical dilute hypochlorite, described as modified Dakin's solution, for prevention of radiation dermatitis in people with head and neck cancer undergoing radiation therapy. The design is listed as parallel group, with triple masking. The record does not specify which groups of people were masked or describe how masking was maintained. Stanford University is named as the sponsor, and the study status is completed.

Participants were assigned to modified Dakin's solution or saline placebo. The assigned solution was applied topically to the skin of the arm up to 3 hours before each radiation treatment. The brief description explains that radiation therapy was determined by the patient's needs and the radiation oncologist's judgment, and was not explicitly defined by dose or duration. The intervention therefore accompanied clinical radiation care rather than a single fixed radiation schedule described in the record.

Enrollment is listed as 132. The primary outcome analysis includes 53 participants in the modified Dakin's solution group and 55 in the placebo group. The registry explicitly says that participants who did not complete radiation treatment were not included in this outcome. The reason for the difference between the enrollment total and these outcome group sizes, beyond that statement, is not reported in the registry record.

The primary endpoint is a binary participant outcome: whether SRDSS Grade E or greater radiation dermatitis occurred. Assessment was described as taking place at baseline and through the treatment course. The endpoint timeframe extends from the first radiation treatment up to 10 weeks after radiation treatment completion, with the record cautioning that the available information does not allow greater precision. The registry lists three outcome measures and one analysis, along with two secondary outcomes: time to Grade E radiation dermatitis and pain associated with radiation dermatitis. Additional details of the trial's original sample-size rationale, analysis protocol, or planned interim analyses 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

Analysis population for the primary outcome, as defined in the registry: Not all participants completed radiation treatment, and are not included in the outcome.

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 Radiation Dermatitis, measured over From first radiation treatment up to 10 weeks after completion of radiation treatment. Because much of the study data was not provided by the prior investigator to the current Responsible Party, it is not possible to be more precise than stated..

The primary endpoint counts participants who experienced SRDSS Grade E or greater radiation dermatitis. Under the Stanford Radiation Dermatitis Scoring System, Grade E is moist desquamation, while Grade F includes bleeding, ulceration, and/or infection. The record says Grade E is roughly equivalent to CTCAE Version 4.03 Grade 3 radiation dermatitis, described as moist desquamation in areas other than skin folds and creases, or bleeding induced by minor trauma or abrasion.

The outcome is reported as a count and proportion in each treatment group, rather than as a measurement with a dispersion estimate. A binary endpoint is useful for expressing how many participants crossed a defined severity threshold during the stated follow-up period. It makes the group comparison directly about experiencing the specified event, rather than about the full distribution of dermatitis grades or the timing of onset.

The stated timeframe runs from the first radiation treatment through up to 10 weeks after completion of radiation treatment. The record says that a more precise period cannot be given because much of the study data was not available to the current Responsible Party. The endpoint was assessed on the arms, and participants who did not complete radiation treatment were excluded from this outcome. The registry does not report further detail about how missing outcome observations among the included participants were handled.

As a general statistical point, a threshold outcome is straightforward to interpret but does not convey changes below that threshold. It also depends on consistent assessment and follow-up. The posted counts therefore describe the recorded occurrence of Grade E or greater dermatitis in the analyzed groups; they do not, by themselves, capture every aspect of dermatitis severity or its course.

7. Results Posted in the Registry

• Arm I (Modified Dakin's Solution): 64.2% (34/53) versus 65.5% (36/55) on control; risk difference -1.3 percentage points (95% CI -19.3 to 16.7), risk ratio 0.98 (0.74–1.29); unadjusted two-proportion z-test p = 0.887.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is binary: each participant is counted according to whether SRDSS Grade E or greater radiation dermatitis occurred during the stated follow-up. For a binary outcome, each treatment group can be described by its number of participants with the event and its number assessed. The registry reports 34 of 53 in the modified Dakin's solution group and 36 of 55 in the placebo group. The group counts and denominators are the basis for the unadjusted comparison.

A risk difference expresses the contrast between the event proportions in two groups by subtraction. The recalculated risk difference is -0.013, with the modified Dakin's solution group as the comparison group and placebo as the reference. The negative sign indicates that the observed proportion was lower in the modified Dakin's solution group in this sample. This is a descriptive direction, not proof of a causal benefit. The estimate is unadjusted, meaning it is calculated from the posted group summaries rather than a model that adjusts for other participant characteristics.

A confidence interval describes uncertainty around an estimate under the assumptions of the method used. The recalculated 95% interval runs from -0.193 to 0.167. Because it includes zero, the data are compatible with no risk difference; because it also extends in both directions, they are compatible with lower or higher event proportions in the modified Dakin's solution group. The interval's breadth is important: the estimate is not sufficiently precise to distinguish a small or moderate contrast from no contrast with confidence. A confidence interval is not a range guaranteed to contain the true value, nor is it a probability statement about this particular interval.

The posted re-calculation uses an unadjusted comparison of the event counts. The registry reports a chi-squared test and p = .8872. A chi-squared test evaluates whether the observed group distribution is inconsistent with a null hypothesis of no association between treatment group and the binary outcome. The recalculated p-value is 0.887. Such a p-value is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of a possible difference. The estimated contrast and its interval are needed alongside the test result.

As a general statistical explanation, a p-value is calculated under a null model and describes how unusual data at least as incompatible with that model would be, if the model and its assumptions held. A large p-value can occur when the underlying group contrast is small, when there is substantial variability, or when the data are too limited to distinguish a contrast from random variation. It should not be interpreted as proof of no effect. Conversely, a small p-value would not by itself show that a contrast is clinically important or free of bias.

The registry's report of a chi-squared test does not include a test statistic, degrees of freedom, or a confidence interval for that analysis. Those details are not reported in the registry record. The available comparison is therefore best read through the reported event counts, the recalculated risk difference and interval, and the sponsor's p-value, rather than as a fully documented analysis model.

For a binary event, over-dispersion is not the same issue as it is for count outcomes. General explanation: over-dispersion arises when observed variability exceeds what a statistical model assumes. If it is present in a model that assumes less variability, standard errors can be too small and uncertainty can be understated. The registry record does not report an over-dispersion assessment or a model that would allow one to assess it for this endpoint.

Randomization is intended, as a general design principle, to balance participant characteristics across groups on average. It does not guarantee exact balance in a particular study, and it does not address every source of bias after assignment, such as incomplete follow-up or inconsistent outcome assessment. The record gives the randomized, parallel, triple-masked design label but does not report the randomization sequence method, allocation concealment, masking details, adherence, or other implementation details. These are not grounds to assume a problem occurred; they are limits on what can be evaluated from the registry entry.

The primary outcome excludes participants who did not complete radiation treatment. General statistical explanation: an analysis restricted to participants meeting a post-randomization condition can differ from an analysis that retains all randomized participants, especially if completion is related to prognosis, treatment assignment, or outcome. The registry does not report the reasons for noncompletion, whether any other participants lacked outcome assessments, or sensitivity analyses for missing outcomes. It is therefore not possible to determine how those issues affect the estimate.

There are two listed secondary outcomes, but their estimates and analyses are not reported in the registry record. The number of analyses reported is one. No multiplicity adjustment or testing hierarchy is reported. General explanation: when several outcomes or comparisons are tested, the chance of at least one apparently noteworthy result can increase unless the analysis plan accounts for the number and relationship of tests. Without the full plan and secondary results, the primary p-value should be interpreted as the reported single analysis, not as a comprehensive account of all planned analyses.

10. Confidence Intervals and Precision

The recalculated risk difference is -0.013, and its 95% confidence interval extends from -0.193 to 0.167. The point estimate is close to zero, while the interval spans zero and values on both sides. This means the observed data do not pin down the direction or size of the group contrast with high precision. The interval is consistent with no difference as well as with a lower or higher event proportion in the modified Dakin's solution group.

Precision concerns how narrowly an estimate is determined by the data and method. A confidence interval is a way to display that uncertainty, not a guarantee about the true value and not a range of equally likely values. Here, the width of the interval is a central part of interpretation: a near-zero estimate should not be mistaken for strong evidence that the groups are equivalent. The registry does not report an equivalence margin or a noninferiority margin, and the analysis is not described as an equivalence or noninferiority analysis.

The participant counts for the primary endpoint are 53 and 55, while total enrollment is 132. The record says that participants who did not complete radiation treatment are not included in the outcome, but it does not provide further detail about all participants absent from the endpoint denominators. Uncertainty in the estimate is therefore not the only consideration; the definition of the analyzed population and the handling of unavailable outcomes also matter.

The sponsor's reported chi-squared p-value is .8872, while the unadjusted recalculation gives 0.887. These values indicate that the test did not identify a statistically significant group difference under the reported analysis. A p-value cannot replace the interval: it does not show the range of contrasts compatible with the data or establish that a difference is absent. The interval and the excluded-participant information should be read together when considering how precisely the posted results address the primary question.

11. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm for 80% power and participants per arm for 90% power. They are not total events. The planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set as a stated fraction of the observed effect. The figures are planning illustrations calculated from the observed effect, not the trial's own original design assumptions, which are not reported in the registry record.

In plain language, the 80% power column describes the approximate number of participants per group that a hypothetical study would need to have an 80% chance of detecting the specified effect, if the assumptions used for that calculation held. The 90% power column uses a higher target chance of detecting that same specified effect and therefore gives a larger planning requirement. These are prospective planning quantities, not descriptions of the chance that the completed trial found a result.

The rows consider planning for 100%, 75%, and 50% of the observed effect. A smaller effect is harder to distinguish from random variation, so planning to detect a smaller effect requires more participants. The listed values make that pattern visible across the fractions. The observed effect used in these illustrations is the recalculated, unadjusted risk difference, not a treatment effect established as true.

The displayed curve should be read as a visual companion to these planning estimates, not as a separate observed result. It relates the assumed effect size to the resulting planning requirement under the stated assumptions. Neither the curve nor the participant figures represent observed power for this completed trial; observed power is not an informative substitute for interpreting the estimated effect and its confidence interval.

These calculations do not show that the original trial was designed around the observed result. The registry record does not report the original sample-size justification, planned effect size, or design power. Because the planning illustration uses the observed effect, its values are especially sensitive to that estimate and should not be treated as a recommended enrollment target without an independently justified effect and design plan.

12. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.655; treatment proportion p₁ = 0.642; average p̄ = 0.648.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.6754 = 1.3238.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6753 = 0.5684.
4. n = (1.3238 + 0.5684)² / (-0.0130)² = 21,068.1, rounded up to 21,069 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.654545454545455                          # control proportion
p1 <- 0.641509433962264                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(2369835)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 21,069 (80% power), 28,204 (90% power)
 75% of observed effect: n per arm = 37,376 (80% power), 50,035 (90% power)
 50% of observed effect: n per arm = 83,916 (80% power), 112,339 (90% power)
power.prop.test: 21068.1 
Simulated power at n = 21,069 per arm: 0.801 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

13. Analyses Reported by the Sponsor

The registry reports a chi-squared analysis with p = .8872. The unadjusted recalculation from the posted summary counts gives p = 0.887. These values are close, and the record does not identify a discrepancy. There is consequently no flagged conflict that would call for the sponsor's analysis to take precedence over the recalculation.

The sponsor's p-value addresses evidence against the null hypothesis under the reported chi-squared test. It is not an estimate of the size of the group difference. The recalculation adds an unadjusted risk difference of -0.013 and a 95% confidence interval from -0.193 to 0.167, which show the estimated contrast and its uncertainty. Both forms of information are useful, but the p-value alone cannot indicate whether any possible difference is small or large.

The registry does not report further chi-squared details, including the test statistic or a confidence interval from the sponsor's analysis. The recalculation is based on the posted event counts and denominators and does not adjust for other variables. It should therefore be understood as a simple summary-based comparison, rather than a reconstruction of an undocumented analysis plan. The available record does not establish whether additional planned analyses were conducted outside the posted result.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists two secondary outcomes: time to Grade E radiation dermatitis and pain associated with radiation dermatitis. Their results are not reported in the registry record. One analysis is reported, but the registry entry does not describe a testing hierarchy, a multiplicity adjustment, or how primary and secondary outcomes were to be interpreted together.

General statistical explanation: multiplicity refers to making several statistical comparisons or tests. The more tests that are considered, the greater the chance that at least one result may appear noteworthy by chance, depending on how the tests relate to one another. Prespecified priorities, adjustment procedures, or other analysis strategies can help address this issue. Since those details are not reported, the primary p-value should be read as the result of the posted analysis and not as evidence that all potential comparisons have been accounted for.

The primary outcome includes participants who completed radiation treatment; the record says those who did not complete treatment were not included in this outcome. It does not report the reasons for noncompletion, a complete accounting of participants excluded from the endpoint analysis, or whether missing outcomes occurred among those otherwise eligible for analysis. It also does not report imputation, sensitivity analyses, or other methods for handling missing data. Those details are not reported in the registry record.

General statistical explanation: missingness can affect a group comparison when the likelihood of an unavailable outcome is related to treatment group or to the outcome itself. Excluding participants may then make the analyzed groups differ from the groups created by randomization. This is a potential methodological concern, not evidence that such bias occurred in this trial. The registry information is insufficient to assess its direction or size.

The primary endpoint analysis is therefore not documented as an analysis of every enrolled participant. The record does not state whether the original protocol specified an intention-to-treat analysis, a per-protocol analysis, or another population definition. It also does not give details of adherence or protocol deviations. No claim about those planned methods can be made from the registry entry. These gaps constrain interpretation of how the primary estimate relates to all randomized participants and to any analyses that may have been planned but are not posted.

15. 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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: radiation dermatitis (53.1%), aspiration, pneumonia (3.1%), cardiac arrest (1.6%), upper gastrointestinal hemorrhage (1.6%), acneiform rash (1.6%).

The registry lists serious adverse event figures by group. For Arm I, 64 participants were at risk for serious adverse events and 34 were affected; for Arm II, 68 were at risk and 36 were affected. The listed deaths are 1 in Arm I and 0 in Arm II. These safety counts are distinct from the primary outcome denominators of 53 and 55.

The most frequently listed serious adverse event term is radiation dermatitis, reported as 53.1%. Other listed terms are aspiration, pneumonia at 3.1%, cardiac arrest at 1.6%, upper gastrointestinal hemorrhage at 1.6%, acneiform rash at 1.6%, and mucositis at 1.6%. These percentages are reported as listed; the registry entry does not provide further detail in this summary about their calculation or the number of events represented by each term.

Serious adverse event listings describe events recorded during the study and do not, on their own, establish that an event was caused by the assigned solution. The record does not provide additional causal attribution or a detailed comparison of safety risks. The at-risk group sizes also differ from the primary endpoint analysis group sizes, so the safety counts should not be substituted for the primary endpoint denominators or interpreted as the same analysis population.

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

The posted primary outcome is a count of participants with SRDSS Grade E or greater radiation dermatitis. It records 34 participants in the modified Dakin's solution group and 36 in the placebo group, using endpoint groups of 53 and 55, respectively. The unadjusted risk difference is -0.013, and its 95% confidence interval ranges from -0.193 to 0.167. The sponsor's chi-squared analysis reports p = .8872.

These results describe the observed groups and indicate that the posted test did not identify a statistically significant difference. They do not establish that the treatments are equivalent, that the true difference is zero, or that a difference in either direction is impossible. The confidence interval includes zero and extends to contrasts on both sides, so the estimate is not precise enough to resolve the direction and size of a possible difference.

The trial record also has boundaries that matter for what can be concluded. The primary outcome excludes participants who did not complete radiation treatment. The registry does not provide a fuller account of those not included, of missing outcomes, or of how such data were handled. It gives a broad endpoint timeframe, from the first radiation treatment up to 10 weeks after completion, and states that greater precision is not possible from the available study data. These details limit how completely the result can be tied to all enrolled participants and a precise follow-up interval.

The primary result is not a result for the secondary outcomes. Although time to Grade E dermatitis and pain associated with radiation dermatitis are listed, their findings are not reported in the registry record. The result also does not establish what would happen under different radiation schedules, application practices, or populations not described in the record.

In general, a statistical test and confidence interval answer a narrower question than whether an intervention should be used in care. They quantify features of the observed comparison under a method and its assumptions; they do not supply a clinical recommendation. The appropriate statistical reading is limited to the recorded outcome, groups, analysis population, and uncertainty described in the registry entry.

17. Why This Trial Matters Statistically

This trial illustrates why a treatment comparison should not be reduced to its p-value. The sponsor's chi-squared test reports p = .8872, and the recalculated result is p = 0.887. Neither value conveys the estimated size of the contrast. The risk difference and its confidence interval add that information: the estimate is -0.013, but the interval extends from -0.193 to 0.167 and includes differences in both directions.

The example also highlights the importance of matching denominators to the question. The registry reports enrollment of 132, while the primary outcome counts use 53 participants in one group and 55 in the other. Participants who did not complete radiation treatment were excluded from this outcome. Without additional accounting, enrollment alone does not tell a reader how many participants contributed to the endpoint or how the excluded participants might affect interpretation.

Outcome definitions are another important statistical feature. The primary measure is a threshold event, SRDSS Grade E or greater, rather than the entire range of dermatitis grades or the timing of the event. Such definitions can support a clear binary comparison, but they also focus interpretation on crossing a particular severity threshold. The record lists time to Grade E dermatitis and pain as secondary outcomes, but their results are not reported.

Finally, a planning calculation based on an observed effect is not a substitute for the original trial's design rationale. The registry does not report the original sample-size justification. The planning illustrations depend on their stated assumptions and on the observed effect used to construct them; they are not observed power and do not establish what the original study was designed to detect. Together, these features make the record a useful example of interpreting an estimate, uncertainty, analysis population, and design information as distinct parts of a trial result.

18. 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 primary endpoint excludes participants who did not complete radiation treatment. The registry does not report the reasons for noncompletion or enough detail to determine how many other participants lacked endpoint data. It also does not describe how missing outcomes were handled. This leaves uncertainty about how the analyzed group relates to all enrolled participants and whether exclusions could affect the group comparison.

The outcome timeframe is broad: from the first radiation treatment up to 10 weeks after completion. The record explicitly says that greater precision is not possible because much of the study data was not available to the current Responsible Party. The radiation therapy dose and duration were not explicitly defined, as treatment was based on participant needs and the radiation oncologist's judgment. This makes the treatment context less standardized in the registry description.

The registry identifies triple masking but does not state who was masked or how masking was maintained. It does not report the randomization method, allocation concealment, adherence, or details of outcome-assessment procedures. The primary assessment used the Stanford Radiation Dermatitis Scoring System, but the record does not provide additional information about assessor training or consistency. These details cannot be evaluated from the registry entry.

The registry reports one analysis and a sponsor chi-squared p-value, but does not give a full analysis plan or the original sample-size justification. Results for the two listed secondary outcomes are not reported. The number of planned or unposted analyses, any interim analyses, and any multiplicity strategy are not reported in the registry record. These limitations prevent a fuller assessment of prespecification and the completeness of the reported results.

These are limits of the available registry information, not proof that the trial procedures were inadequate. They mean that the posted primary comparison should be interpreted with attention to its restricted outcome population, broad timeframe, and the substantial uncertainty in the estimated risk difference.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Modified Dakin's Solution in Reducing Radiation-Induced Dermatitis in Patients With Head and Neck Cancer Undergoing Radiation Therapy — NCT02369835.
• Registry record last updated 2024-01-30; status last verified 2024-01.
• Results first posted 2019-09-17.
• 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.

22. Record Summary

NCT02369835 is a completed randomized phase 3 parallel-group study sponsored by Stanford University. It compared topical modified Dakin's solution with saline placebo in participants with head and neck cancer receiving radiation therapy. The registry identifies the study as triple masked.

The primary outcome was the number of participants experiencing SRDSS Grade E or greater radiation dermatitis, assessed from the first radiation treatment up to 10 weeks after completion. The posted counts are 34 of 53 in the modified Dakin's solution group and 36 of 55 in the placebo group. Participants who did not complete radiation treatment were not included in this outcome.

The unadjusted recalculated risk difference is -0.013, with a 95% confidence interval from -0.193 to 0.167 and p = 0.887. The registry reports a chi-squared p-value of .8872. The interval is broad and includes differences in either direction. Results for the listed secondary outcomes are not reported in the registry record.