Table 2.

Four-year OS and BCSS of the two groups.

Group	Before matching		After matching
	4-year OS	4-year BCSS	4-year OS	4-year BCSS
Chemotherapy	98.6%	99.3%	97.5%	98.8%
Non-chemotherapy	96.6%	99.4%	95.2%	98.8%
p value	0.001	0.083	<0.001	0.128
Total	98.2%	99.4%	97%	99%

BCSS, breast cancer-specific survival; OS, overall survival.