This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Immunohistochemical Evaluation of Protein P16 Expression in Ovarian Germ Cell Tumors. (NCT04283773), a registered phase not stated study. The primary outcome is P16 Evaluation in Ovarian Germ Cell Tumors.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04283773 |
| Phase | Phase not stated |
| Condition | Ovarian Neoplasms, Germ Cell Tumors, Immunohistochemistry |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 62 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Assiut University |
| Results posted | Yes |
2. Clinical Question
Population
The study includes ovarian tissue from three groups: 22 cases of malignant ovarian germ cell tumors, 20 mature cystic teratomas, and 20 normally apparent ovaries. The malignant group includes dysgerminoma, yolk sac tumor, and immature teratoma. The registry record does not report further participant characteristics.
Intervention
The tissue assessment uses an anti-p16 antibody to evaluate p16 immunohistochemical staining. Ki67 antibody is specified for malignant cases only. These are laboratory assessment procedures, not clinical treatments administered to participants.
Comparator
The three tissue groups are described separately, but the registry record does not describe randomized allocation or a like-for-like controlled comparison. Allocation is not stated. Comparisons across the groups therefore should not be read as randomized treatment effects.
Primary question
The primary outcome is p16 evaluation in ovarian germ cell tumors, using a semiquantitative score based on staining intensity and the extent of stained cells. The registry record does not report the resulting scores, group summaries, or statistical comparisons, so it does not establish how staining differed among the groups.
The registry background describes p16 as a cell-cycle regulatory protein and notes that its expression in ovarian germ cell tumors has been poorly investigated. The study's stated purpose is to assess p16 staining in these lesions and related ovarian tissue. Its design can describe staining patterns in the sampled specimens, but the available record does not provide results with which to assess whether any pattern was observed.
3. Trial Design
This completed study is registered as NCT04283773 and is sponsored by Assiut University. The registry lists a start date of 2019-12-24 and a primary completion date of 2021-04-01. Enrollment is 62. Its status is COMPLETED. The study is classified as “other” rather than as a randomized clinical comparison.
The groups comprise 22 malignant ovarian germ cell tumor cases, 20 mature cystic teratomas, and 20 normally apparent ovaries. The malignant cases include dysgerminoma, yolk sac tumor, and immature teratomas. The registry describes p16 antibody staining in all groups and Ki67 antibody staining in malignant cases only. The stated antibody exposure is overnight, with assessment up to 3 days for each run of sections assessed.
The registry record does not state allocation, masking, or a prospective assignment process. It also does not describe recruitment procedures, eligibility criteria, specimen selection, or whether tissue groups were matched on participant characteristics. Because allocation is not stated and the arms are not a like-for-like control comparison, differences between groups would be descriptive rather than evidence of a randomized causal effect.
The primary outcome concerns p16 expression assessed by visual estimation of the percentage and location of positive cells, followed by a semiquantitative score. A secondary outcome is correlation between the p16 cytoplasmic score and FIGO staging of malignant ovarian germ cell tumors. Although the record lists three outcome measures and three analyses, detailed analysis procedures are not reported in the registry record. The study's own sample-size justification is 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
| Stage | IHC of P16 Expression in Malignant Ovarian Germ Cell Tumors. | IHC of P16 Expression in Benign Ovarian Germ Cell Tumors ( Mature Cystic Teratomas). | IHC of P16 Expression in Normal Ovarian Tissues. |
|---|---|---|---|
| STARTED | 22 | 20 | 20 |
| COMPLETED | 22 | 20 | 20 |
| NOT COMPLETED | 0 | 0 | 0 |
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.
| Characteristic | Unit | Malignant Ovarian Germ Cell Tumors ( MOGCTs). | Mature Cystic Teratomas. | Normally Apparent Ovaries. | Total |
|---|---|---|---|---|---|
| Participants analysed | 22 | 20 | 20 | 62 | |
| Age, Continuous | years | 16.5 (12 to 23) | 31.5 (14 to 50) | 50 (42 to 64) | 30 (12 to 64) |
| Sex: Female, Male: Female | Participants | 22 | 20 | 20 | 62 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 22 | 20 | 20 | 62 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 |
| Region of Enrollment: Egypt | participants | 22 | 20 | 20 | 62 |
| P16 cytoplasmic expression | units on a scale | 7 (0 to 8) | 4 (0 to 6) | 0 (0 to 4) | 6 (0 to 8) |
| P16 nuclear expression | units on a scale | 6 (0 to 8) | 4 (0 to 5) | 0 (0 to 3) | 4 (0 to 8) |
6. Primary Endpoint
The registry lists the primary outcome as P16 Evaluation in Ovarian Germ Cell Tumors, measured over Antibody exposure overnight, assessed up to 3 days for each run of sections assessed..
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | units on a scale |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is p16 immunohistochemical evaluation in ovarian germ cell tumors. For each lesion, the registry describes visual estimation of the percentage of p16-positive cells and the location of positive signals, nuclear or cytoplasmic. The staining is scored separately for intensity and extent. Intensity ranges from no staining, scored 0, to strong staining, scored 3. Extent ranges from 0% positive cells, scored 0, to 81-100%, scored 4, with intermediate categories also specified.
The final immunoreactive score is the product of the intensity and extent scores. The stated minimum is 0 and the maximum is 12; possible scores are 0, 1, 2, 3, 4, 6, 8, 9, and 12. The primary outcome is summarized as a median with a full range, in units on a scale. A median describes the central position of the observed scores, while the full range describes their minimum-to-maximum spread. These summaries suit a bounded, discrete scoring system without requiring the score to be treated as a continuous measure with evenly spaced values.
The score gives a structured way to describe staining intensity and distribution. However, the registry record does not report the observed scores, medians, or ranges, so the staining level and variability in each group cannot be assessed from the recorded results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes the intended assessment in detail, but does not report numerical results for the primary outcome. No median p16 score or full range is reported for malignant ovarian germ cell tumors, mature cystic teratomas, or normally apparent ovaries. No result for the secondary correlation with FIGO staging is reported in the registry record. Consequently, the posted results cannot establish the direction, size, or precision of differences in staining, or the strength of any relationship with stage.
The record identifies 22 malignant cases, 20 mature cystic teratomas, and 20 normally apparent ovaries. Those are group counts, not outcome summaries. They indicate the stated composition of the study groups but do not reveal how many specimens had absent, weak, moderate, or strong staining, nor the distribution of final immunoreactive scores. The score is formed from intensity and extent, so distinct staining patterns can lead to different component scores. Without the observed component or final scores, the pattern cannot be reconstructed.
The study is not described as randomized, and allocation is not stated. The groups represent different tissue categories rather than arms assigned to alternative therapies. Any contrast among them should therefore be interpreted as a comparison of measured tissue characteristics, not as an effect caused by assigning an intervention. The registry record does not report information on factors that might affect comparability among groups.
The planned primary summary is a median and full range. A median alone would not describe all features of the score distribution, and a full range can be influenced by extreme observations. General statistical interpretation would also consider the individual values or other distributional summaries where available, but those are not reported in the registry record. No confidence interval, hypothesis-test result, or estimate of uncertainty for the primary outcome is reported in the registry record.
The registry lists p16 cytoplasmic score correlation with FIGO staging as a secondary outcome. It does not specify the correlation method, give a correlation estimate, or report its uncertainty. The relationship therefore cannot be quantified or characterized from this record. The number of analyses is listed, but their statistical methods and results are not detailed.
The adverse-event record lists zero participants at risk and zero affected for serious and other adverse events in each of the three groups, with zero deaths. Because the recorded at-risk counts are zero, these entries do not establish that adverse events were actively assessed and absent among the enrolled cases. The record does not describe adverse-event collection procedures. Overall, the most defensible reading is that the registry states a scoring plan and group composition, while the outcome evidence needed to interpret p16 expression is not reported in the registry record.
9. Statistical Methods Explained
The registry describes a semiquantitative immunohistochemical scoring method. It records how staining intensity and the extent of positive cells are translated into component scores, and how those components form the final immunoreactive score. The record specifies a median and full range as the primary outcome summary. It does not report an inferential statistical plan, test results, or estimates of uncertainty.
How does the score work?
Intensity is graded from no staining, scored 0, through weak staining, scored 1, and moderate staining, scored 2, to strong staining, scored 3. The extent component is based on the percentage of stained cells: 0% is scored 0; 1-10% is scored 1; 11-50% is scored 2; 51-80% is scored 3; and 81-100% is scored 4. The intensity score is multiplied by the extent score. The registry gives a minimum final score of 0, a maximum of 12, and possible values of 0, 1, 2, 3, 4, 6, 8, 9, and 12.
General statistical explanation: a composite score can summarize more than one aspect of an observation, but its meaning depends on how the components are defined and combined. Here, a larger score can arise from stronger staining, a greater extent of stained cells, or both. The product does not preserve the separate component values, so the same final score may reflect different combinations of intensity and extent. Reporting component-level results alongside the final score can help distinguish those patterns, but such results are not reported in the registry record.
Why use a median and full range?
The outcome is discrete and bounded, with a limited set of possible values. General statistical explanation: the median is the central observation after values are ordered and is less affected by extreme values than the mean. The full range gives the lowest and highest observed values, conveying the total spread but not how observations are distributed between those endpoints. Neither summary alone shows the frequency of each score. The registry specifies this summary format but does not report the actual medians or ranges.
The registry says that positive-cell percentage and signal location are visually estimated for neoplastic components. General statistical explanation: visual scoring can involve observer judgment, so reliable measurement depends on consistent scoring procedures. Information about the number of readers, reader training, blinding, adjudication, or reproducibility is not reported in the registry record. It is therefore not possible to assess how measurement variability was controlled.
What is reported about comparisons?
The record lists three outcome measures and three analyses but does not give the analysis methods, the comparisons performed, or their results. It does not report whether scores were analyzed as ordinal or numerical values, whether any adjustment was made, or which statistical tests were used. The association between cytoplasmic score and FIGO staging is a listed secondary outcome, but its correlation method and estimate are not reported in the registry record.
General statistical explanation: a confidence interval expresses uncertainty around an estimated quantity under a specified statistical model. A hypothesis test evaluates compatibility between observed data and a stated null model. Neither can be interpreted without the estimate, its uncertainty or test result, and relevant methods. No confidence intervals or p-values for the outcomes are reported in the registry record.
How should planning calculations be read?
The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. This description is not the study's design justification. General statistical explanation: a sample-size calculation depends on assumptions about the target effect, variability, allocation, and analysis. A planning illustration is conditional on those assumptions and does not describe the precision actually achieved. It is not observed power. The study's own sample-size justification and the numerical planning outputs are not reported in the registry record.
That illustration also refers to comparisons between two arms. The registered study describes three tissue groups and is not a randomized comparison. The planning assumptions should therefore not be treated as evidence that the study was designed or analyzed as a two-arm trial. No adjustment for multiple comparisons or strategy for handling incomplete outcome data is reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists three outcome measures and three analyses, but does not report which statistical procedures correspond to each outcome, whether all analyses were prespecified, or how multiple analyses were handled. No multiplicity adjustment, hierarchy of outcomes, or distinction between confirmatory and exploratory analyses is reported in the registry record. General statistical explanation: when several hypotheses are examined, the chance of at least one apparently notable result can increase if each is evaluated separately. An analysis plan can address that issue, but no such plan is described.
Missing outcome data and exclusions are also not described. The registry record does not report whether all enrolled cases had evaluable p16 staining, how missing scores were handled, or whether any specimens were excluded from analysis. It does not specify analysis populations or provide a flow of cases from enrollment to outcome assessment. Therefore, the group counts alone do not establish how many cases contributed to each reported outcome.
The adverse-event entries list zero at risk and zero affected in each group, with zero deaths. The at-risk counts do not indicate an evaluable population for adverse-event rates, and event ascertainment methods are not reported in the registry record. These entries should not be taken as evidence that adverse events were assessed and did not occur.
The record does not report interim analyses, stopping rules, or a missing-data sensitivity analysis. The protocol's handling of incomplete scores, the analysis populations, and the approach to multiplicity are not reported in the registry record. These omissions limit assessment of how complete and selective the posted analyses may be.
11. What the Result Does, and Does Not, Mean
The registry record establishes that p16 staining was to be assessed with a specified semiquantitative score in three ovarian tissue groups. It documents the group sizes, the score components, the final score range, and the intended primary summary. It also identifies correlation between cytoplasmic score and FIGO staging as a secondary outcome. These details explain what the study set out to measure.
The record does not report the actual primary scores, group medians or ranges, or the secondary correlation result. It therefore cannot show whether p16 staining was more or less prominent in one tissue group, how much variation was present, or whether staining was associated with FIGO stage. No conclusion about the direction or size of an observed relationship can be made from the registry information described.
Even if group summaries were available, the design would remain a comparison of tissue categories without stated random allocation. General statistical explanation: observational group differences may reflect both the feature of interest and differences in the groups or how specimens were selected and assessed. A difference would not by itself identify a causal effect. The registry does not report enough information about recruitment, matching, confounding factors, or measurement procedures to evaluate those issues.
The score is a measure of immunohistochemical staining, not a direct measure of clinical benefit or patient outcome. The use of antibody reagents in laboratory assessment should not be interpreted as administration of a therapeutic intervention. The record does not provide evidence about treatment effects, prognosis, or clinical decision-making. The study may contribute a descriptive assessment of staining if results are available, but the registry record does not report those results. Interpretation must therefore remain limited to the design and measurement plan rather than claims about p16 expression in the enrolled cases.
12. Why This Trial Matters Statistically
This study raises a measurement question in a setting where the registry background describes p16 expression in ovarian germ cell tumors as poorly investigated. Statistically, its central feature is the conversion of visual staining assessments into an ordinal, bounded composite score. The score combines intensity and extent, making clear definitions and consistent application important for interpreting comparisons across tissue groups.
The registry makes several parts of the scoring rubric explicit: the intensity categories, the stained-cell extent categories, the multiplication rule, and the possible final scores. That transparency allows readers to understand what the endpoint represents and what it leaves implicit. In particular, the final score does not uniquely identify the underlying combination of staining strength and extent, so the component-level information can matter to biological interpretation.
The study also illustrates why design and analysis context matter. Malignant tumors, mature cystic teratomas, and normally apparent ovaries are distinct tissue groups, not randomized arms. Their comparison can describe patterns in the specimens assessed, but a causal interpretation would require additional design and analysis information. The registry does not report such details or the outcome values themselves.
Finally, the registry's description of the endpoint is more informative than its reporting of results and analysis methods. Without group summaries, uncertainty estimates, and details of the analyses, readers cannot evaluate the magnitude or precision of any finding. This distinction between a defined measurement plan and reported evidence is important when assessing what a registry record can support statistically.
13. 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 trial-specific limitation is that the registry record does not report the primary outcome values. The planned median and full range for p16 immunoreactive scores are absent for each tissue group. The secondary correlation between cytoplasmic score and FIGO staging is listed, but its estimate and analysis are not reported. Thus, the central empirical question cannot be answered from the recorded results.
The study includes three distinct tissue groups and is not described as randomized. Allocation is not stated, and the record does not explain how specimens or participants were selected. It also does not report participant characteristics, matching, or potential confounding variables. Any observed differences, if reported elsewhere, would need interpretation in light of those design features.
Measurement may be affected by the visual estimation of staining percentage and signal location. The registry specifies the scoring rubric but does not report reader number, blinding, reproducibility, or procedures for resolving disagreement. It is therefore unclear how scoring consistency was assessed. Since the final score multiplies intensity and extent, it can also conceal distinct component patterns if only the composite is summarized.
Missingness, exclusions, analysis populations, multiplicity, and the detailed statistical analysis plan are not reported in the registry record. Adverse-event entries show zero participants at risk, so they do not establish event-free follow-up. The registry describes a sample-size planning illustration, but the study's own sample-size justification is not reported in the registry record. Together, these gaps limit assessment of precision, completeness, and the robustness of any conclusions.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Immunohistochemical Evaluation of Protein P16 Expression in Ovarian Germ Cell Tumors. — NCT04283773.
- Registry record last updated 2021-09-08; status last verified 2021-08.
- Results first posted 2021-09-08.
- 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.
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17. Record Summary
NCT04283773 is a completed study sponsored by Assiut University, with enrollment of 62. The registry lists a start date of 2019-12-24 and a primary completion date of 2021-04-01. The groups are 22 malignant ovarian germ cell tumor cases, 20 mature cystic teratomas, and 20 normally apparent ovaries.
The primary outcome is p16 immunohistochemical evaluation using a score based on staining intensity and extent, summarized as a median and full range. Ki67 antibody is specified for malignant cases only. A secondary outcome concerns correlation between p16 cytoplasmic score and FIGO staging.
The registry record does not report the primary outcome values, the secondary correlation result, detailed analysis methods, or the study's sample-size justification. The study is not described as a randomized comparison, and allocation is not stated.