Estimation of Prognosis of the Individual with Primary Breast Cancer and its Applications

involvement, B scoring 2 – low node involvement and C scoring 3 – high node or multiple node in-volvement or involvement of both axillary and inter-nal mammary chains + Tumour Size maximum di-ameter in cm weighted down by a factor of 0.2 (ie) NPI = Grade + LN Stage + (Size × 0.2). This gives an NPI range between 2.04 for a 2 mm, grade 1, node negative tumour and (since the Index was only ap-plied for ‘operable ’ tumours below 5 cm diameter) to 7.0 for a 5 cm, grade III, stage C tumour. This Index was initially used to divide to three pa-tient groups – the Good Prognostic Group with a 10 year survival of 86 %, a Moderate Prognostic Group with a 10 year survival of 60 % and a Poor Prognos-tic Group with a 10 year survival of 18 %. The NPI was validated intra-laboratory (3) in a new patient set and inter-laboratory and internationally, most notably by the Danish Co-operative Breast Group in over 9,000 patients (4) (Table 1), and in Sweden (5) and Italy (6). With larger numbers it became clini-cally useful to divide the patients into five groups