Breast Cancer Recurrence Risk Calculator — Nottingham Prognostic Index
The Nottingham Prognostic Index (NPI) is a validated clinical tool that combines tumour size, histological grade and lymph node involvement to estimate prognosis after breast cancer surgery. Enter your pathology values to calculate the NPI score and approximate 10-year disease-specific survival.
cm
Lymph node stage
Histological grade
NPI = 0.2 × tumour size + lymph node score + histological grade
- 1
Tumour size term
0.2 × 2 cm = 0.4 - 2
Add lymph node score
0.4 + 1 = 1.4 - 3
Nottingham Prognostic Index
1.4 + 2 = 3.40NPI = 0.2 × tumour size (cm) + lymph node score + histological grade
How does this calculator work?
NPI = 0.2 × tumour size (cm) + lymph node score (1–3) + grade (1–3). Scores ≤ 2.4 = Excellent (~85% 10-year survival), 2.4–3.4 = Good (~70%), 3.4–5.4 = Moderate (~55%), > 5.4 = Poor (~30%). Based on the validated Nottingham Prognostic Index; does not replace oncologist advice or modern biomarker testing.
Formula
How this is calculated
The NPI was developed by Todd et al. (1987) and validated by Galea et al. (1992) at the City Hospital Nottingham on thousands of patients. It combines three independently prognostic factors: tumour size in centimetres (multiplied by 0.2 to match the other variables' scale), a lymph node score (1 = node-negative, 2 = 1–3 positive axillary nodes, 3 = four or more positive nodes), and the Elston-Ellis histological grade (1 = well differentiated, 2 = moderately differentiated, 3 = poorly or undifferentiated).
The resulting NPI score maps to four prognostic groups: Excellent (≤ 2.4, ≈ 85% 10-year breast-cancer–specific survival), Good (2.4–3.4, ≈ 70%), Moderate (3.4–5.4, ≈ 55%) and Poor (> 5.4, ≈ 30%). Survival figures are approximate averages from the validation cohort using 2026 published data; actual prognosis also depends on receptor status (ER, PR, HER2), Ki-67 proliferation index, and systemic treatment received.
This index predicts disease-specific survival in early invasive breast cancer. It is not validated for in situ disease (DCIS), inflammatory carcinoma or metastatic disease at presentation, and it does not incorporate modern biomarkers such as Oncotype DX recurrence score. Always interpret results together with your oncology team.
Frequently asked questions
You need three values from your pathology (histopathology) report after surgery: the size of the largest invasive tumour focus in centimetres, the lymph node status (how many axillary nodes contained cancer), and the histological grade assigned by the pathologist (1, 2 or 3). These appear on every standard UK and Australian breast pathology report; US reports use the same grading system.
The NPI was derived and validated in large prospective cohorts and has been independently reproduced across multiple countries. Its prognostic discrimination is comparable to the Adjuvant! Online model for ER-positive, HER2-negative tumours. However, it does not include receptor status or Ki-67, so modern multivariable tools such as PREDICT Breast (which does include these) can give a more refined estimate.
No. The NPI gives a probability estimate for a population group — not a certainty for an individual. Many patients in the "Moderate" or "Poor" groups remain disease-free long-term, particularly with modern adjuvant therapy. The score is one input into treatment planning; it does not predict your personal outcome.
TG we-Calculate Editorial Team. (2026). Breast Cancer Recurrence Risk Calculator — Nottingham Prognostic Index [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/breast-cancer-recurrence-risk-calculator
TG we-Calculate Editorial Team. "Breast Cancer Recurrence Risk Calculator — Nottingham Prognostic Index." TG we-Calculate. 2026. https://we-calculate.com/calculator/breast-cancer-recurrence-risk-calculator.
TG we-Calculate Editorial Team, "Breast Cancer Recurrence Risk Calculator — Nottingham Prognostic Index," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/breast-cancer-recurrence-risk-calculator
@misc{wecalculate_breast_cancer_recurrence_risk_calculator, title = {Breast Cancer Recurrence Risk Calculator — Nottingham Prognostic Index}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/breast-cancer-recurrence-risk-calculator}}, year = {2026}, note = {TG we-Calculate} }
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