The Nottingham Prognostic Index

The Nottingham Prognostic Index was calculated using the following formula: tumor size in cm x 0.2 + lymph-node stage (1, 2 or 3) + histologic grade (1, 2 or 3). When only node negative patients are analysed the lymph-node stage is 1 for all cases. The Nottingham "excellent prognosis" group was defined according to Galea et al. as those patients with an index value = 2.4 (ref).

Nottingham Prognostic Index Score

Excellent prognosis group <=2.4
Good prognosis group <=3.4
Moderate prognosis group >3.4 and <=5.4
Poor prognosis group >5.4

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.

NPI calculator

Tumor size in cm
Histologic grade
Number of positive axillary lymph nodes