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Clinical calculator summary

New Magee Equation 1 (2013)

A linear-regression pathology estimate, not an actual genomic-assay result.

Evidence-based context for fast calculator use

Purpose:
Reproduce the source equation and historical estimated category without treatment or testing advice.
Population:
Primary invasive ER-positive, pathologically node-negative breast carcinoma with untreated complete surgical pathology.
Factors:
Nottingham score, ER/PR H-scores, source-era HER2 category, Ki-67, invasive size
Reference:
Klein et al. Modern Pathology 2013;26:658-664. doi:10.1038/modpathol.2013.36.
HomeNew Magee Equation 1 (2013 pathology-based estimated recurrence score)
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New Magee Equation 1 (2013 pathology-based estimated recurrence score)

Confirm all listed conditions before entering the six pathology values.

Clinical Context & Background

This route implements New Magee Equation 1 from Klein et al. 2013 using Nottingham histologic score, ER and PR H-scores, source-era HER2 category, invasive tumor size, and Ki-67.
The 2013 HER2 category is copied from pathology established as negative (IHC 0/1+ or IHC 2+ with FISH <1.8), equivocal (IHC 2+ with FISH 1.8-2.2), or positive (IHC 3+ or IHC 2+ with FISH >2.2). This route does not rederive HER2 under current guidelines.
It returns a pathology-based estimated score and historical estimated category. It is not the proprietary 21-gene assay, an individualized recurrence probability, chemotherapy-benefit estimate, testing-substitution decision, or treatment recommendation. Original Magee, equations 2/3, averages, modified Magee, decision algorithms, TAILORx, and RxPONDER are excluded.
Formula Logic
15.31385 + 1.4055×Nottingham - 0.01924×ER H-score - 0.02925×PR H-score + HER2 coefficient + 0.78677×size(cm) + 0.13269×Ki-67

Reference Data

Raw unrounded New Magee Equation 1 estimateHistorical estimated category
<18Low
18 through 30 inclusiveIntermediate
>30High

Clinical Workflow

Use, Interpret, And Continue The Patient Pathway

Expand for workflow guidance, limitations, examples, and related next steps.

When To Use

  • Use New Magee Equation 1 (2013 pathology-based estimated recurrence score) when full-precision New Magee Equation 1 estimate from complete source-compatible surgical pathology; explicitly not an actual Oncotype DX result.
  • Confirm that the patient, diagnosis, disease phase, and available inputs match the cited model before calculation.

How To Interpret

  • Interpret the displayed result using the calculator-specific formula and reference table, spanning <18 through >30.
  • A boundary result should prompt input verification and clinical review rather than false precision.

What To Do Next

  • Integrate the result with invasive versus in-situ status, stage, receptor biology, treatment timing, genomic testing, comorbidity, and patient goals.
  • Document the inputs, result, timing, and clinical context so the assessment can be reproduced.

Limitations

  • Do not interchange screening-risk, DCIS, invasive prognosis, genomic, and post-neoadjuvant tools.
  • The result supports clinician judgment and does not independently determine treatment.

Validated Population

patients undergoing breast cancer risk, staging, pathology, recurrence, or treatment-benefit assessment

How to apply this result

For a representative case, verify Magee Equation 1 applicability, Nottingham histologic score, ER H-score, calculate the result, and confirm that its classification matches the highlighted reference band before continuing the disease-specific pathway.

Calculation verification history

Verified
  1. : Production browser revalidation

    • Three source-backed cases passed through visible production controls at estimates 4.98, 20.54, and 68.55.
    • Low, Intermediate, and High estimated categories rendered across zero-valued pathology inputs and representative profiles.
    • No unexpected N/A, literal undefined value, stale control, unsupported gauge, or browser-console error was observed.
    Download latest production check (Excel)

    Case-level evidence is retained in validation/browser-revalidation/magee-breast-2026-08-03.json.

  2. : Not-applicable receipt corrected and browser-revalidated locally

    • A source-incompatible or uncertain population selection now shows a Magee-specific estimate-not-assigned receipt instead of generic missing-or-invalid-input wording.
    • Ten visible-browser cases passed across 11 submissions, covering all three estimated categories, raw 18 and 30 threshold transitions, HER2 branches, applicability, and reset/repeat.
    • The New Magee Equation 1 coefficients, full-precision estimate, and raw category mapping remain unchanged and pass 12,288/12,288 independent assertions.

    Case-level local remediation evidence is retained in validation/browser-production/magee-breast.local-remediation.json; the original production finding remains retained separately.

  3. : Production browser validation

    • Ten source-backed cases were exercised on the public production route through visible browser controls; 9/10 case records passed their expected-versus-observed assertions across 11 visible submissions.
    • Overall browser status: failed-ui-and-console. medium: The correct Not applicable result also displays the generic trace Required input is missing or invalid despite a complete intentional not-confirmed applicability choice. | medium: Production emitted minified React error #418 during the route load.
    • 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/magee-breast.json.

  4. : Model identity corrected

    • Locked the route to New Magee Equation 1 (2013) and separated it from the original equation, equations 2/3, averages, decision algorithms, and the actual proprietary assay.
    • Removed TAILORx/RxPONDER and genomic-testing substitution framing.
  5. : Calculation and inputs corrected

    • Restored the exact published coefficients, HER2 terms, historical category boundaries, full-precision classification, two-decimal display, and unclamped regression output.
    • Replaced favorable defaults and Number coercion with an exact 12-key surgical-pathology and source-applicability contract.
  6. : Full validation completed

    • 12288/12288 deterministic assertions passed, including all 5376 lattice combinations against a separately encoded literal oracle.
    • This is software implementation verification, not prospective or independent clinical validation, assay equivalence, or treatment guidance.
  7. : Public form simplified

    • Combined six source-population and pathology-context questions into one early applicability confirmation.
    • Preserved all six equation determinants: Nottingham score, ER H-score, PR H-score, source-era HER2 category, Ki-67, and invasive size.
    • The compact adapter projects confirmed applicability into the unchanged strict 12-key engine; declined or uncertain applicability stops before pathology entry.

    Public-form parity is covered by the calculator entry-burden audit; the verified equation, coefficients, thresholds, and report remain unchanged.

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

Is this an Oncotype DX result?

No. It is a pathology-based regression estimate and cannot reproduce the proprietary assay, recurrence probability, confidence intervals, or treatment benefit.

How is HER2 entered?

Enter the externally established source-era category. The route does not reinterpret current HER2 testing or derive a category from raw IHC/FISH data.

Evidence-based oncology decision support. Verify with clinical guidelines.