Survival Outcomes of Breast-Conserving Therapy versus Mastectomy in Early-Stage Breast Cancer, Including Centrally Located Breast Cancer: A SEER-Based Study

Table 1

Comparison of baseline characteristics between BC patients undergoing BCT and mastectomy from 2000 to 2015.

	Mastectomy		BCT		-value
	N	%	N	%
Year					< 0.001
2000–2003	11629	18.8%	21347	18.0%
2004–2007	13304	21.5%	26570	22.4%
2008–2015	37010	59.7%	70635	59.6%
Age, years					< 0.001
18–63	43013	69.4%	77456	65.3%
64–72	11678	18.9%	28108	23.7%
73–79	7252	11.7%	12988	11.0%
Race					< 0.001
White	48880	78.9%	97410	82.2%
Black	6167	10.0%	11112	9.4%
Others	6896	11.1%	10030	8.5%
Histologic type					< 0.001
IDC	56391	91.0%	110183	92.9%
ILC	5552	9.0%	8369	7.1%
Laterality					0.698
Left	31577	51.0%	60549	51.1%
Right	30366	49.0%	58003	48.9%
Grade					< 0.001
I	10720	17.3%	30405	25.6%
II	26520	42.8%	51602	43.5%
III/IV	24703	39.9%	36545	30.8%
T stage					< 0.001
T1a	4283	6.9%	9494	8.0%
T1b	9083	14.7%	28637	24.2%
T1c	23164	37.4%	52213	44.0%
T2	25413	41.0%	28208	23.8%
N stage					< 0.001
N0	42422	68.5%	92001	77.6%
N1	15855	25.6%	21863	18.4%
N2	2530	4.1%	3417	2.9%
N3	1136	1.8%	1271	1.1%
ER					< 0.001
Negative	14117	22.8%	19820	16.7%
Positive	47826	77.2%	98732	83.3%
PR					< 0.001
Negative	20801	33.6%	31423	26.5%
Positive	41142	66.4%	87129	73.5%
Chemotherapy					< 0.001
No or unknown	33049	53.4%	68605	57.9%
Yes	28894	46.6%	49947	42.1%

BCT, breast-conserving therapy; IDC, invasive ductal carcinoma; ILC, invasive lobular carcinoma; ER, estrogen receptor; PR, progesterone receptor.