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Breast Cancer Recurrence Risk Calculator

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Estimate breast cancer prognosis using the Nottingham Prognostic Index from tumor size, nodes, and grade. A general educational estimate, not a genomic test.

Reviewed by the thecalcu.com team · Last updated July 9, 2026

Tumor Size
cm
Lymph Node Involvement
Tumor Grade

Nottingham Prognostic Index

0.00

Prognosis Category

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This is a general educational estimate only — not a diagnosis or a replacement for your oncologist. The NPI does not incorporate hormone receptor status, HER2 status, or genomic data the way tests like Oncotype DX or MammaPrint do. Always discuss your personal prognosis and treatment plan with your treating oncologist.

What is a Recurrence Risk (NPI)?

This calculator computes the Nottingham Prognostic Index (NPI), a well-established, formula-based prognostic tool that combines tumor size, lymph node involvement, and tumor grade into a single score. Published by Galea, Blamey, and Ellis in 1992 and reproduced in numerous studies since, the NPI remains a widely referenced way to categorize general prognosis following breast cancer surgery.

Please read this carefully: this is a general educational estimate only, and it is absolutely not a substitute for your oncologist. Your treating oncologist has access to your complete pathology report, hormone receptor and HER2 status, imaging, treatment history, and overall health, none of which this simplified three-factor calculator can see. The NPI is also fundamentally different from personalized genomic recurrence tests like Oncotype DX or MammaPrint, which analyze gene activity within the tumor itself and were developed specifically to guide chemotherapy decisions. This tool cannot and does not replace that kind of testing.

If you or someone you love has recently received a breast cancer diagnosis, please know that this calculator's purpose is purely educational, to help you understand a formula your care team may reference, not to predict your personal outcome. Prognosis categories are statistical groupings across many patients, and modern treatment continues to improve outcomes meaningfully across every NPI band.

Why Use This Calculator?

Understanding the terms and numbers that come up during cancer treatment discussions can help you feel more informed and prepared for conversations with your care team. The NPI is one of the classic prognostic tools referenced in oncology literature and training, and seeing how the formula combines your own pathology numbers can make those conversations feel less opaque.

It is also a useful reference for students and early-career clinicians learning how established prognostic formulas are constructed from routinely available pathology data, before moving on to more complex modern tools that incorporate genomic and biomarker information.

Who Should Use This Calculator?

Patients who want to understand a number their oncologist has mentioned, being able to see how tumor size, node status, and grade combine into the NPI can make follow-up conversations with your care team feel more grounded, while always deferring final interpretation to your oncologist.

Family members and caregivers trying to understand general prognostic terminology used during a loved one's treatment planning discussions.

Medical, nursing, and oncology students studying classic prognostic scoring systems as part of their education, using this calculator as a quick reference alongside textbook and journal sources.

Clinicians who want a fast reference calculation during case discussions or teaching sessions, understanding that clinical decisions always require the complete patient picture beyond this three-factor formula.

What Insights Does This Calculator Give You?

Nottingham Prognostic Index (NPI) (the primary output) is the combined score from tumor size, lymph node stage, and tumor grade, typically ranging from about 2 to 6.5 in published data.

Prognosis Category translates the raw NPI score into one of three published bands, excellent, good/moderate, or poor, based on the original Galea et al. 1992 cutoffs, shown with a color-coded badge for quick reference. Remember these are population-level statistical categories, not individual predictions.

How to use this Recurrence Risk (NPI) calculator

  1. Locate your tumor size in centimeters from your surgical pathology report and enter it using the slider or exact-entry field.

  2. Select your lymph node involvement category, 0 nodes, 1-3 nodes, or 4 or more nodes, as reported by your pathologist.

  3. Select your tumor grade, Grade 1, 2, or 3, also from your pathology report.

  4. Read your NPI score, the large number in the result card, and note the prognosis category badge beneath it.

  5. Bring your result to your next oncology appointment as a starting point for discussion, not as a final answer, and ask your oncologist to explain how it fits into your complete treatment picture.

  6. Ask about genomic testing such as Oncotype DX or MammaPrint if you haven't already discussed it, since these tests provide additional, more individualized information the NPI formula does not capture.

Show formula & methodology ↓Show less ↑

Formula & Methodology

Nottingham Prognostic Index
NPI = (0.2 × Tumor Size in cm) + Lymph Node Stage + Tumor Grade

Lymph Node Stage

| Nodes Involved | Stage Points |
|---|---|
| 0 nodes | 1 |
| 1-3 nodes | 2 |
| ≥4 nodes | 3 |

Tumor Grade

| Grade | Points |
|---|---|
| Grade 1 (well differentiated) | 1 |
| Grade 2 (moderately differentiated) | 2 |
| Grade 3 (poorly differentiated) | 3 |

Published Prognosis Bands (Galea et al., 1992)
NPI < 3.4         → Excellent prognosis NPI 3.4 - 5.4     → Good / moderate prognosis NPI > 5.4         → Poor prognosis

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Worked Example:

A pathology report shows a 2.5 cm tumor, 2 involved lymph nodes, and Grade 2 histology.

| Variable | Value |
|---|---|
| Tumor Size | 2.5 cm |
| Lymph Node Stage | 1-3 nodes → 2 pts |
| Tumor Grade | Grade 2 → 2 pts |

NPI = (0.2 × 2.5) + 2 + 2 = 0.5 + 2 + 2 = 4.5

Score falls between 3.4 and 5.4 → Good / moderate prognosis

This general educational estimate is a starting point for discussion only. The patient's oncologist will factor in hormone receptor status, HER2 status, overall health, and treatment response, none of which this formula sees, when discussing her actual individualized prognosis and treatment plan. See the Breast Cancer Risk Calculator for a separate, simplified tool estimating baseline population risk factors rather than post-diagnosis prognosis.

Frequently Asked Questions

What is the Nottingham Prognostic Index (NPI)?
The Nottingham Prognostic Index is a well-established, formula-based prognostic tool published by Galea and colleagues in 1992 that combines tumor size, lymph node involvement, and tumor grade into a single score. It has been widely reproduced and validated in breast cancer research over more than three decades as a general indicator of prognosis following surgery.
Is this calculator a substitute for advice from my oncologist?
No, please read this carefully. This calculator provides a general, formula-based educational estimate only. It is not a diagnosis, not a personalized treatment recommendation, and not a substitute for your treating oncologist, who has access to your complete pathology report, biomarker results, and overall health picture. Every decision about your treatment and prognosis should be made with your care team, not from an online tool.
How is the NPI different from Oncotype DX or MammaPrint?
Oncotype DX and MammaPrint are genomic tests that analyze the activity of specific genes within the tumor tissue itself to predict recurrence risk and likely benefit from chemotherapy. The NPI, by contrast, uses only three readily available clinical measurements, tumor size, node status, and grade, and does not incorporate any genomic or biomarker data. These are complementary but fundamentally different types of tools, and your oncologist may use one, both, or neither depending on your specific case.
What do the NPI score bands mean?
The published cutoffs group scores into three bands: below 3.4 is generally described as an excellent prognosis category, 3.4 to 5.4 as good-to-moderate, and above 5.4 as poor. These bands come from the original Galea et al. 1992 study and have been widely reproduced, but individual outcomes vary significantly and these categories are population-level statistical groupings, not individual predictions.
What is tumor grade and why does it matter for the NPI?
Tumor grade describes how abnormal cancer cells look under a microscope compared to normal breast tissue, ranging from Grade 1 (well differentiated, cells look more like normal tissue) to Grade 3 (poorly differentiated, cells look very abnormal and tend to grow faster). Higher grade generally correlates with a higher NPI score and a less favorable prognosis category, though grade is only one of three factors in the formula.
Does a 'poor prognosis' category mean a bad outcome is certain?
No. Prognosis categories describe population-level statistical tendencies among many patients with similar scores, they are not a prediction for any single individual. Modern treatment has continued to improve outcomes across all NPI bands since the original 1992 study, and your specific treatment plan, response to therapy, and many other factors this simplified tool doesn't capture all influence your actual outlook. Your oncologist is the only person who can meaningfully interpret your prognosis.
Why doesn't this calculator ask about hormone receptor or HER2 status?
The original Nottingham Prognostic Index formula uses only tumor size, lymph node stage, and grade, it predates routine hormone receptor and HER2 testing in clinical practice. Modern oncology incorporates these additional biomarkers into treatment decisions extensively, but they fall outside the scope of the classic NPI formula this calculator implements.
How is lymph node stage determined?
Lymph node stage in this calculator follows the classic three-tier NPI grouping: stage 1 for no involved nodes, stage 2 for one to three involved nodes, and stage 3 for four or more involved nodes. This is typically determined by your surgeon and pathologist through sentinel node biopsy or axillary lymph node dissection at the time of surgery.
Can I use this calculator before I have a complete pathology report?
You can, but the result will only be as accurate as the numbers you enter. All three inputs, tumor size, node status, and grade, typically come from your final surgical pathology report, so waiting for that complete report before relying on any NPI-based estimate is strongly recommended.
How do I use the Breast Cancer Recurrence Risk Calculator?
Enter your tumor size in centimeters from your pathology report, then select your lymph node involvement category and tumor grade from the dropdown menus. The calculator instantly computes your NPI score and shows the associated prognosis category.
Does this calculator store any of my health information?
No. All calculations run entirely in your browser. None of the values you enter are transmitted to or stored on any server, and everything is cleared the moment you close the page.
Also known as
Nottingham Prognostic Index calculatorNPI calculatorbreast cancer prognosis calculatorbreast cancer survival estimateNPI breast cancer score