Clinical calculator summary
Original Nottingham Prognostic Index (NPI-3)
Clinical calculator summary
Original Nottingham Prognostic Index (NPI-3)
A three-factor postoperative pathology index derived in 1982.
Evidence-based context for fast calculator use
- Purpose:
- Assign the source-defined Good, Moderate, or Poor historical prognostic group.
- Population:
- Adult women with primary operable invasive nonmetastatic breast carcinoma and complete postoperative pathology before treatment.
- Factors:
- Largest invasive diameter, Positive axillary-node count, Nottingham histologic grade
- Reference:
- Haybittle et al. Br J Cancer. 1982;45:361-366. doi:10.1038/bjc.1982.62
Original Nottingham Prognostic Index, three-group model (NPI-3, 1982)
Clinical Context & Background
Raw NPI = (0.2 x largest invasive diameter in cm) + node stage (1-3) + Nottingham grade (1-3)Reference Data
| Original NPI-3 group | Raw score | Scope |
|---|---|---|
| Good prognostic group | <= 3.4 | Historical postoperative group |
| Moderate prognostic group | > 3.4 to <= 5.4 | Historical postoperative group |
| Poor prognostic group | > 5.4 | Historical postoperative group |
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 Original Nottingham Prognostic Index, three-group model (NPI-3, 1982) when source-locked postoperative NPI-3 interpretation from invasive tumor size, positive axillary-node count, and Nottingham histologic grade.
- 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 Good prognostic group through Poor prognostic group.
- 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 Largest invasive tumor diameter, Pathologically positive axillary nodes, Nottingham histologic grade, calculate the result, and confirm that its classification matches the highlighted reference band before continuing the disease-specific pathway.
Calculation verification history
Verified
Calculation verification history
Verified: Production browser revalidation
- Three source-backed cases passed through visible production controls at NPI 2.40, exact boundary 3.40, and 10.00.
- Good and Poor prognostic groups and the exact lower threshold rendered as expected.
- No unexpected N/A, literal undefined value, stale control, unsupported gauge, or browser-console error was observed.
Case-level evidence is retained in validation/browser-revalidation/nottingham-prognostic-index-breast-cancer-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 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/nottingham-prognostic-index-breast-cancer.json.
: Public form simplified
- Reduced seven separate public questions to one early applicability confirmation plus the three result-determining inputs: invasive size, positive nodes, and Nottingham grade.
- The compact adapter projects confirmed scope into the unchanged strict seven-key engine; declined scope hides the clinical form and produces no score.
- Existing 1,024/1,024 engine checks and the shared compact-adapter audit passed.
: Model identity corrected
- Locked the route to the original 1982 three-group NPI-3 model.
- Excluded NPI(6), four-group variants, NPI+, genomic, and treatment-benefit identities.
: Calculation and scope corrected
- Replaced pre-scored favorable defaults with raw invasive size, positive-node count, Nottingham grade, and enforceable postoperative scope fields.
- Applied full-precision formula and exact 3.4 and 5.4 boundaries without precomparison rounding.
- Removed unsupported survival percentages and treatment guidance.
: Validation completed
- Passed 1,024/1,024 independent deterministic assertions.
- Verified strict input handling, source scope, UI serialization, trace, public content, ledger, and mirrored report artifacts.
Software implementation verification only; not prospective clinical validation.
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
Does this calculator estimate an individual survival probability?
No. It returns only the original NPI-3 historical prognostic group and does not emit cohort survival percentages as patient-specific predictions.
Can this be used after neoadjuvant therapy?
No. Post-neoadjuvant size and nodal measurements are outside this source-locked postoperative pretreatment implementation.
Is this NPI(6) or NPI+?
No. This route is locked to the original three-group 1982 model and excludes later six-group, biomarker, and genomic variants.
Evidence-based oncology decision support. Verify with clinical guidelines.