Table 1.

Characteristics of study participants

Study	Number of breast cancer deaths	Total number of Breast cancer patients	Estrogen Receptor (ER) status- Negative (%)	Average age at Diagnosis (±SD)	Follow-up time in years (±SD)	N-stage	M-stage	HER2 status
POSH stage- 1	236	536	370 (69.2%)	35.7 (3.8)	4.1 (2.0)	N0-248 N1-262 NA-25 535	M0-481 M1-50 NA-4 535	Negative-369 Positive-92 NA-74 535
POSH stage- 2	468	1518	423 (27.4%) NA-8	35.7 (3.7)	4.8 (1.4)	N0-645 N1-838 NA-35	M0-1470 M1-42 NA-6	Negative-756 Positive-399 NA-363
Helsinki non- early onset specific participants	301	805	230 (30.0%) NA-39	56.8 (12.4)	7.2 (2.9)	N0-338 N1-446 NA-21	M0-740 M1-57 NA-8	Negative-402 Positive-86 NA-317

NA=not available,

HER2= Human Epidermal Growth Factor Receptor 2, N-stage=metastasis to lymph node, M-stage=metastasis