Clinical calculator summary
Original 1997 RTOG RPA for brain metastases
Clinical calculator summary
Original 1997 RTOG RPA for brain metastases
A three-class baseline prognostic decision tree using KPS, age, primary-tumor control, and extracranial-metastasis status.
Evidence-based context for fast calculator use
- Purpose:
- Reproduce the original RTOG prognostic class without converting historical cohort survival into an individualized estimate or treatment rule.
- Population:
- Adults with confirmed brain metastases assessed at baseline in the setting of historical RTOG radiotherapy cohorts.
- Factors:
- KPS above or below 70, Age below 65, Primary-tumor control, Extracranial metastases
- Reference:
- Gaspar et al. IJROBP. 1997;37(4):745-751. doi:10.1016/S0360-3016(96)00619-0.
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RPA (Brain Metastases)
years
Clinical Context & Background
This calculator reproduces the original 1997 Radiation Therapy Oncology Group (RTOG) Recursive Partitioning Analysis for adults with confirmed brain metastases. It uses pretreatment Karnofsky Performance Status, completed age, primary-tumor control, and extracranial-metastasis status.
Class III takes precedence whenever KPS is below 70. Among patients with KPS at least 70, Class I requires age below 65, a controlled primary tumor, and no extracranial metastases; every other combination is Class II. Age exactly 65 is therefore Class II.
The reported median survival values are historical cohort observations from RTOG radiotherapy trials, not individualized survival predictions or treatment recommendations. This model is not for screening, diagnosis, post-treatment reassessment, or selecting radiation, surgery, systemic therapy, or palliative care. Modern diagnosis-specific GPA tools may provide more contemporary prognostic stratification where applicable.
Formula Logic
Original 1997 RTOG RPA decision tree: Class III when KPS <70; otherwise Class I only when age <65, the primary tumor is controlled, and extracranial metastases are absent; Class II for every other combination.Reference Data
| RPA Class | Original 1997 criteria | Historical median overall survival |
|---|---|---|
| Class I | KPS >=70, age <65, controlled primary, no extracranial metastases | 7.1 months |
| Class II | Every other combination with KPS >=70 | 4.2 months |
| Class III | KPS <70, regardless of other predictors | 2.3 months |
Clinical Workflow
Use, Interpret, And Continue The Patient Pathway
Expand for workflow guidance, limitations, examples, and related next steps.
Clinical Workflow
Use, Interpret, And Continue The Patient Pathway
Expand for workflow guidance, limitations, examples, and related next steps.
When To Use
- Use for baseline prognostic classification in an adult with confirmed brain metastases.
- Use pretreatment KPS and disease-status information.
How To Interpret
- KPS <70 defines Class III with precedence.
- With KPS >=70, all three remaining favorable criteria are required for Class I; otherwise the result is Class II.
- Age exactly 65 does not meet the Class I age criterion.
What To Do Next
- Interpret the historical class alongside contemporary multidisciplinary assessment.
- Consider modern diagnosis-specific GPA tools when clinically applicable.
Limitations
- Not for screening, diagnosis, post-treatment reassessment, or recurrence detection.
- Does not recommend radiation, surgery, systemic therapy, palliative care, or any treatment pathway.
- Historical median survival values are cohort observations and not individualized predictions.
Validated Population
1,200 evaluable patients from three historical RTOG brain-metastasis radiotherapy trials conducted from 1979 to 1993.
Calculation verification history
Verified
Calculation verification history
Verified: Production browser revalidation
- Three source-backed RPA cases passed through visible production controls across Classes I, II, and III, including age exactly 65.
- No unexpected N/A, literal undefined value, stale control, or browser-console error was observed.
Case-level evidence is retained in validation/browser-revalidation/rpa-brain-2026-08-03.json.
: Production browser validation
- Ten source-backed cases were exercised on the public production route through visible browser controls; 10/10 case records passed their expected-versus-observed assertions across 11 visible submissions.
- Overall browser status: failed-console. medium: Production emitted minified React error #418 during route loads/reloads used by this run.
- Case-level inputs, expected and observed results, reset/repeat behavior, failure reproductions, and console evidence are retained in the production-browser evidence record.
Case-level production evidence is retained in validation/browser-production/rpa-brain.json.
: Browser input adapter corrected and reverified
- Accepted finite number values already normalized by the shared calculator form while retaining strict malformed-input rejection.
- No equation, cutoff, unit, classification, or applicability rule changed; calculator-specific verification and the calculator-wide browser-input audit passed.
: Full validation test
- 320/320 exhaustive decision, exact age-boundary, strict-input, UI/reset, trace, historical-outcome, immutability, registry, and no-panel checks passed with zero classification mismatches.
- Scope is the original 1997 baseline RTOG RPA classification for adults with confirmed brain metastases; no panel calculates RPA or inherits this status.
: Input-contract and clinical-context correction
- Locked Class III precedence for KPS <70 and the primary-source Class I age criterion of age <65; age exactly 65 is Class II.
- Removed favorable defaults, unsafe numeric coercion, missing/extra-field acceptance, fractional ages, and unsupported categorical values.
- Added immutable input snapshot, four-step decision trace, matched class row, historical-cohort wording, exclusions, and a modern diagnosis-specific GPA note.
Verification confirms the calculator implementation against the cited model; it is not independent clinical validation, regulatory approval, or medical advice.
Related Tools
Frequently Asked Questions
When should RPA (Brain Metastases) be used?
Use it for patients with primary or metastatic central nervous system disease in the setting described by the model when all required inputs and the intended clinical setting are confirmed.
Can RPA (Brain Metastases) determine treatment by itself?
No. Interpret the result with the cited evidence, complete clinical assessment, current guidelines, and patient-specific goals.
Evidence-based oncology decision support. Verify with clinical guidelines.