Nottingham Prognostic Index
Nottingham Prognostic IndexA histopathological system for predicting the prognosis for a particular patient with breast cancer, based on three parameters found to have the greatest value in predicting invasive tumour behaviour:
(1) Tumour size in cm;
(2) Lymph node stage: 1 = node negative; 2 = 1 to 3 positive nodes; 3 = 4+ positive nodes, or apical node, or any positive axillary node plus internal mammary node;
(3) Histological grade based on tubule/acinar/glandular formation, nuclear atypia/pleomorphism and frequency of mitoses, with each accorded a grade of 1 to 3.
The NPI is based on a formula, NPI = 0.2 X tumour size + lymph node stage (1, 2 or 3) + histologic grade (1, 2 or 3), where the higher the NPI score the worse the prognosis. Patients with an NPI score of ≤ 3.0 have an equivalent survival to age-matched controls (3% annual mortality). Patients with an NPI score of ≤ 3.4 have a good prognosis. Women with an NPI of ≥ 5.4 have a poor prognosis, and may be advised to undergo more aggressive adjuvant therapy. Choice of adjuvant treatment for patients with an NPI score between 3.4 and 5.4 depends on other variables—e.g., hormone receptor status and the patient’s general health.