Smoothed hazard for death in ethnically Chinese breast cancer patients having mastectomy alone. (a) Lymph node negative. (b) Lymph node positive. (c) Pathological T1. (d) Pathological T2 or T3. (e) Premenopausal. (f) Postmenopausal patients. (g) Well to moderately differentiated. (h) Poorly differentiated. (i) ER positive. (j) ER negative. Note that the tail of the curve was removed because of the small number of available data. ER, oestrogen receptor.