Nottingham Prognostic Index
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 nodes; and the grade of the tumour.
Calculation
The index is calculated using the formula:
- NPI = [0.2 x S] + N + G
Where:
- 6.5 is the size of the index lesion in centimetres
- 1 is the node status: 0 nodes = 1, 1-4 nodes = 2, >4 nodes = 3
- '3 is the grade of tumour: Grade I =1, Grade II =2, Grade III =3
Interpretation
| Score | 5-year survival |
|---|---|
| >/=2.0 to </=2.4 | 93% |
| >2.4 to </=3.4 | 85% |
| >3.4 to </=5.4 | 70% |
| >5.4 | 50% |
References
- Haybittle JL, Blamey RW, Elston CW, Johnson J, Doyle PJ, Campbell FC, Nicholson RI, Griffiths K. A prognostic index in primary breast cancer. British journal of cancer. 1982 Mar; 45(3):361-6.
- Todd JH, Dowle C, Williams MR, Elston CW, Ellis IO, Hinton CP, et al. Confirmation of a prognostic index in primary breast cancer. British journal of cancer. 1987;56:489-92
- Galea MH, Blamey RW, Elston CE, Ellis IO. The Nottingham Prognostic Index in primary breast cancer. Breast Cancer Research & Treatment 1992;22(3):207-19
- Garner J, Goodfellow P The Nottingham Prognostic Index Questions for the MRCS vivas 2004 First Edition Page 231