Patient number
x1: age at surgery (years)
x2: menopausal status
x3a: tumour size T2 or T3 (>20 mm)
x3b: tumour size T3 (>50 mm)
x4: grade (differentiation)
x5: number of positive lymph nodes
x6: progesterone receptor (pmol/l)
x7: oestrogen receptor (pmol/l)
x8: Hormonal therapy
x9: Chemo therapy
Relapse-free interval (months)
Censoring (0 = censored, 1 = relapsed)
Tumour size (T-stage, 1/2/3)
exp(-0.12 * nodes)