Clinical calculator summary
Graded Prognostic Assessment (GPA) for Brain Metastases
Clinical calculator summary
Graded Prognostic Assessment (GPA) for Brain Metastases
The GPA is a validated prognostic index that estimates survival in patients with brain metastases using four clinical factors, developed from analysis of 1,960 patients in five RTOG trials.
Evidence-based context for fast calculator use
- Purpose:
- Reproduce the original GPA total and matched historical cohort outcome row.
- Population:
- Adults with established brain metastases assessed before treatment, resembling the historical RTOG cohorts.
- Factors:
- Age, Karnofsky Performance Status (KPS), Number of brain metastases, Extracranial metastases
- Reference:
- Sperduto et al. Int J Radiat Oncol Biol Phys. 2008;70(2):510-514.
GPA (Graded Prognostic Assessment)
Clinical Context & Background
Original 2008 GPA = age points + KPS points + brain-metastasis-count points + extracranial-metastasis points (0 to 4 in 0.5-point increments).Reference Data
| GPA Score | Median Survival |
|---|---|
| 0 - 1.0 | 2.6 months |
| 1.5 - 2.5 | 3.8 months |
| 3.0 | 6.9 months |
| 3.5 - 4.0 | 11.0 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 pretreatment prognostic classification in an adult with established brain metastases.
- Enter completed age, pretreatment KPS, the brain-metastasis count, and extracranial-metastasis status.
How To Interpret
- Add the four original source-defined contributions without rounding.
- Match the total to one of four historical outcome rows: 0-1.0, 1.5-2.5, 3.0, or 3.5-4.0.
What To Do Next
- Interpret the historical group alongside contemporary multidisciplinary assessment.
- Consider a diagnosis-specific GPA when clinically applicable.
Limitations
- Not a diagnosis-specific GPA.
- Not for screening, diagnosis, post-treatment reassessment, or treatment selection.
- Historical median survival values are cohort observations, not individualized predictions.
Validated Population
1,960 patients from five historical RTOG brain-metastasis trials.
Calculation verification history
Verified
Calculation verification history
Verified: Production browser revalidation
- Three source-backed GPA cases passed through visible production controls at scores 0.0, 2.5, and 4.0.
- No unexpected N/A, literal undefined value, stale control, or browser-console error was observed.
Case-level evidence is retained in validation/browser-revalidation/gpa-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/gpa-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
- 512/512 exhaustive model, exact age/count/score-boundary, strict-input, UI, trace, historical-outcome, wording, immutability, registry, and no-panel checks passed with zero score or classification mismatches.
- Scope is the original 2008 pretreatment diagnosis-agnostic GPA for adults with established brain metastases; no panel calculates GPA or inherits this status.
: Calculation and input-contract correction
- Replaced favorable pre-scored defaults with completed age, semantic KPS and extracranial categories, and a positive integer brain-metastasis count.
- Corrected age exactly 60 years to 0 points and enforced the original age <50, 50-59, and >=60 boundaries without rounding.
- Added strict exact-key, integer, finite-value, enum, missing/extra-field, coercion, nonfinite, safe-count, and immutability safeguards plus a four-factor trace and cautious historical-cohort wording.
Verification confirms the calculator implementation against the cited model; it is not independent clinical validation, regulatory approval, or medical advice.
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Frequently Asked Questions
When should GPA (Graded Prognostic Assessment) 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 GPA (Graded Prognostic Assessment) 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.