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Clinical calculator summary

Solitary Pulmonary Nodule Malignancy Risk (Mayo)

This calculator implements the exact Swensen et al.

Evidence-based context for fast calculator use

Purpose:
Estimates malignancy probability for a newly discovered, radiologically indeterminate solitary pulmonary nodule using the Swensen 1997 Mayo Clinic model.
Population:
patients undergoing thoracic oncology risk, staging, or nodule assessment
Factors:
Age, Smoking history, Cancer history, Solitary nodule diameter, Nodule margin, Nodule location
Reference:
Swensen SJ, et al. Arch Intern Med. 1997;157(8):849-855. https://pubmed.ncbi.nlm.nih.gov/9129544/
HomeSolitary Pulmonary Nodule Malignancy Risk (Mayo)
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Solitary Pulmonary Nodule Malignancy Risk (Mayo)

years
mm

Clinical Context & Background

This calculator implements the exact Swensen et al. 1997 six-predictor Mayo Clinic equation for a newly discovered, radiologically indeterminate solitary pulmonary nodule measuring 4-30 mm.
The original cohort was historical and chest-radiography-era. Cancer diagnosed within the preceding five years was excluded. Multiple, screening-detected, ground-glass, and part-solid nodules require a different evidence pathway. The result is a pretest probability of malignancy, not mortality, screening eligibility, or a standalone treatment recommendation.
The low/intermediate/high probability bands shown here are a later ACCP guidance overlay and are not part of the original equation.
Primary source: Swensen SJ, et al. Arch Intern Med. 1997;157(8):849-855. https://pubmed.ncbi.nlm.nih.gov/9129544/
Formula Logic
Swensen 1997 Mayo Clinic model: Logit = -6.8272 + (0.0391 * age in years) + (0.7917 * current/former smoker) + (1.3388 * extrathoracic cancer diagnosed >5 years ago) + (0.1274 * nodule diameter in mm) + (1.0407 * spiculation) + (0.7838 * upper-lobe location) Probability (%) = 100 / (1 + exp(-Logit)) Later ACCP probability bands (not part of the 1997 equation): <5% low, 5-65% intermediate, >65% high.

Reference Data

Raw ProbabilityLater ACCP BandInterpretation
<5%LowUse current nodule guidance and clinical context
5-65%IntermediateExact 5% and 65% are included
>65%HighNot a standalone management directive

Clinical Workflow

Use, Interpret, And Continue The Patient Pathway

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

When To Use

  • Use Solitary Pulmonary Nodule Malignancy Risk (Mayo) when estimates malignancy probability for a newly discovered, radiologically indeterminate solitary pulmonary nodule using the Swensen 1997 Mayo Clinic model.
  • 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 <5% through >65%.
  • A boundary result should prompt input verification and clinical review rather than false precision.

What To Do Next

  • Confirm whether the clinical question is screening eligibility, nodule malignancy, staging, or treatment prognosis and move to the corresponding thoracic pathway.
  • Document the inputs, result, timing, and clinical context so the assessment can be reproduced.

Limitations

  • Lung screening, nodule probability, radiology classification, and cancer staging tools answer different questions.
  • The result supports clinician judgment and does not independently determine treatment.

Validated Population

patients undergoing thoracic oncology risk, staging, or nodule assessment

How to apply this result

For a representative case, verify Age, Smoking history, Cancer history, calculate the result, and confirm that its classification matches the highlighted reference band before continuing the disease-specific pathway.

Lung & Thoracic Oncology hubContinue to related calculators and clinical workflow resources.

Calculation verification history

Verified

  1. : Production browser revalidation

    • Three source-backed cases passed through visible production controls at the minimum profile and both display-collision boundaries.
    • The former rounded 5% and 65% contradictions were absent; production displayed <5.0% and >65.0% with matching classifications.
    • 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/mayo-clinic-lung-nodule-malignancy-risk-2026-08-03.json.

  2. : Boundary-safe display and applicability receipt corrected and browser-revalidated locally

    • A raw probability below 5% that rounds to 5.0 now displays <5.0%, and a raw probability above 65% that rounds to 65.0 now displays >65.0%; exact 5.0% and 65.0% remain Intermediate.
    • The recent-cancer or known-malignancy exclusion now shows a Mayo-specific Not Applicable probability-not-assigned receipt instead of an Invalid Input disposition.
    • Ten visible-browser cases passed across 11 submissions; the Swensen 1997 equation and raw bands remain unchanged and pass 259/259 standalone/panel assertions.

    Case-level local remediation evidence is retained in validation/browser-production/mayo-clinic-lung-nodule-malignancy-risk.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; 8/10 case records passed their expected-versus-observed assertions across 11 visible submissions.
    • Overall browser status: failed-ui-and-console. high: A raw probability just below 5% is correctly classified Low Risk (<5%) but rounded and displayed as 5.0%, which visibly contradicts the stated threshold. | high: A raw probability just above 65% is correctly classified High Risk (>65%) but rounded and displayed as 65.0%, which visibly contradicts the stated threshold. | 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/mayo-clinic-lung-nodule-malignancy-risk.json.

  4. : Full validation test

    • 163/163 standalone fixtures and 96/96 lung-panel Mayo-component parity checks passed with zero numerical difference.
    • Herder and the panel maximum-risk synthesis were not validated and remain in review.

  5. : Correction history

    • Corrected the published intercept from -6.8238 to -6.8272 and classified from the unrounded probability.
    • Enforced the source-backed 4-30 mm diameter range and added strict semantic responses with no preselected clinical answers.
    • Added recent-cancer inapplicability, source-era cautions, full-precision trace, and shared raw-result Mayo mapping in the lung panel.

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 Solitary Pulmonary Nodule Malignancy Risk (Mayo) be used?

Use it for patients undergoing thoracic oncology risk, staging, or nodule assessment when all required inputs and the intended clinical setting are confirmed.

Can Solitary Pulmonary Nodule Malignancy Risk (Mayo) 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.