This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record.
1. Trial at a Glance
ENABLE III evaluated whether an early palliative care intervention compared with later entry into the same behavioral intervention affected patient quality of life, end-of-life care outcomes, survival measures, and caregiver outcomes in advanced cancer.
| Feature | ENABLE III |
|---|---|
| Condition | Advanced Cancer |
| Sponsor | Dartmouth-Hitchcock Medical Center |
| Design | Randomized parallel assignment |
| Masking | Single |
| Primary purpose | Supportive Care |
| Interventions | Later entry group (behavioral); Early palliative care intervention (behavioral) |
2. Clinical Question
Population
Patients with advanced cancer and their caregivers.
Intervention
Early palliative care intervention.
Comparator
Later entry group.
Primary question
Does earlier palliative care intervention change patient-centered and caregiver outcomes over time?
3. Trial Design
360 patients
Palliative care
Comparison
Longitudinal outcomes
Early palliative care intervention
Behavioral intervention beginning earlier in the disease course.
Later entry group
Behavioral intervention with later entry.
4. Endpoints
| Endpoint | Time frame | Description |
|---|---|---|
| Change in patient's quality of living over time | Baseline, 6,12,18,24,36 and every 12 weeks until death or end of study | Quality of life, mood, and symptom intensity measures including FACIT-Pal, QUAL-E, and CES-D. |
| Quality of end of life care | Chart review at death and caregiver proxy interview 2-3 months after patient death | End of Life Care Data Collection Form and Quality of Dying and Death Measure. |
| Estimate and compare hazard ratios and median survival before and after 1 year from enrollment | Enrollment until death or end of study | Overall survival comparison between early and later entry groups. |
| Change in caregiver quality of life, burden and grief over time | Baseline, 6,12,18,24,36, and every 12 weeks until patient death or end of study | Caregiver quality of life, burden, depressive symptoms, spiritual well-being, and grief measures. |
5. Planned Analysis
The registry lists the planned primary outcomes but does not report statistical results on ClinicalTrials.gov.
The quality-of-life and caregiver endpoints are longitudinal outcomes measured repeatedly over time. A statistical analysis of these outcomes would typically account for correlation among repeated measurements within the same participant rather than treating each time point as an independent observation.
The survival endpoint would typically be analyzed using time-to-event methods. Hazard ratios compare the estimated event rate between randomized groups over follow-up, while median survival describes the time at which half of the population has experienced the event.
Time-to-event methods account for patients who have different follow-up durations and patients whose event status is not observed before study completion.
6. Statistical Methodology
Longitudinal outcome analysis
Patient quality-of-life and caregiver measures were collected repeatedly over time. Longitudinal statistical models are designed to estimate changes over time while accounting for the fact that measurements from the same person are related.
Time-to-event analysis
The survival endpoint compares outcomes from enrollment until patient death or end of study. Hazard ratios summarize relative differences in event rates between groups during follow-up.
Patient-centered outcomes
Measures such as quality of life, mood, symptoms, caregiver burden, and grief represent multidimensional outcomes. Statistical interpretation requires distinguishing changes in measurement scores from clinically meaningful changes experienced by patients and caregivers.
7. Statistical Methods Explained
Why are repeated measurements important?
ENABLE III collected assessments at multiple time points. Repeated measurements allow investigators to study trajectories rather than only a single baseline-to-endpoint comparison.
Why use survival analysis?
Survival methods are appropriate when the outcome is the time until an event, such as death. They allow inclusion of participants with different lengths of follow-up.
What does a hazard ratio represent?
A hazard ratio describes the relative estimated event rate between groups over time. It is not the same as the proportion of patients experiencing an event.
Why are quality-of-life measures statistically complex?
Quality-of-life scores can change over time, may vary between individuals, and may be affected by missing assessments as disease progresses.
8. Limitations
- No posted results: The ClinicalTrials.gov record does not report statistical estimates for the registered endpoints.
- Longitudinal measurement: Repeated patient and caregiver assessments require methods that account for within-person correlation.
- Missing data: Advanced cancer studies often involve incomplete follow-up because health status changes over time.
- Multiple outcomes: Several patient and caregiver measures were assessed, requiring careful interpretation of multiple comparisons.
- Generalizability: Trial eligibility and study setting influence which patients and caregivers are represented.
9. Why This Trial Matters Statistically
| Concept | How it appears in ENABLE III |
|---|---|
| Randomization | Comparison of early versus later behavioral palliative care intervention. |
| Longitudinal analysis | Repeated quality-of-life and caregiver assessments over time. |
| Survival analysis | Hazard ratio and median survival comparison from enrollment. |
| Patient-reported outcomes | Quality of life, symptoms, mood, burden, grief, and spiritual well-being. |
| Missing data considerations | Important in populations followed until death or end of study. |