Nottingham Prognostic Index
Encyclopedia
The Nottingham prognostic index (NPI) is used to determine prognosis following surgery for breast cancer
. Its value is calculated using three pathological criteria: the size of the lesion
; the number of involved lymph node
s; and the grade
of the tumour.
Where:
Breast cancer
Breast cancer is cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas; those originating from lobules are known as lobular carcinomas...
. Its value is calculated using three pathological criteria: the size of the lesion
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
; the number of involved lymph node
Lymph node
A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
s; and the grade
Grading (tumors)
In pathology, grading is a measure of the cell appearance in tumors and other neoplasms. Some pathology grading systems apply only to malignant neoplasms ; others apply also to benign neoplasms. The neoplastic grading is a measure of cell anaplasia in the sampled tumors arising from the...
of the tumour.
Calculation
The index is calculated using the formula:- NPI = [0.2 x S] + N + G
Where:
- S is the size of the index lesion in centimetres
- N is the number of lymph nodes involved: 0 =1, 1-3 = 2, >3 = 3
- G is the grade of tumour: Grade I =1, Grade II =2, Grade III =3
Interpretation
| Score | 5-year survival |
|---|---|
| >/=2.0 to | 93% |
| >2.4 to | 85% |
| >3.4 to | 70% |
| >5.4 | 50% |