Table 1.

Patient characteristics of 11,850 patients with versus without radiotherapy (RT).

Variables	No RT (N = 8221)		RT (N = 3629)		P value
	N	%	N	%
Age (years)					< 0.001
Median (Range)	59 (18–90)	55 (22–90)
< 55	3090	37.6	1781	49.1
55-	5131	62.4	1848	50.9
Race					0.191
White	6560	79.8	2855	78.7
Black	1259	15.3	575	15.8
Others	347	4.2	177	4.9
Unknown	55	0.7	22	0.6
Charlson-Deyo index					< 0.001
0	6772	82.4	3159	87.0
1	1129	13.7	406	11.2
2 or more	320	3.9	64	1.8
cT					< 0.001
is	21	0.3	11	0.3
1	1369	16.7	428	11.8
2	2836	34.5	1111	30.6
3	1211	14.7	619	17.1
4	1861	22.6	1238	34.1
Unknown	923	11.2	222	6.1
cN					< 0.001
0	2676	32.6	702	19.3
1	2895	35.2	1434	39.5
2	904	11.0	549	15.1
3	822	10.0	706	19.5
Unknown	924	11.2	238	6.6
Grade					< 0.001
1,2	3550	43.2	1417	39.0
3,4	3928	47.8	1905	52.5
Unknown	743	9.0	307	8.5
ER					< 0.001
Positive	6151	74.8	2577	71.0
Negative	1922	23.4	1025	28.2
Unknown	148	1.8	27	0.7
PgR					0.003
Positive	5056	61.5	2157	59.4
Negative	2987	36.3	1440	39.7
Unknown	178	2.2	32	0.9
HER2					0.020
Positive	2084	25.3	1010	27.8
Negative	5621	68.4	2452	67.6
Unknown	516	6.3	167	4.6
Subtypes					< 0.001
Luminal	4578	55.7	1880	51.8
HER2 +	2065	25.1	1000	27.6
Triple-negative	1002	12.2	553	15.2
unknown	576	7.0	196	5.4
Breast surgery					< 0.001
BCS	2276	27.7	893	24.6
Mastectomy	5945	72.3	2736	75.4
Chemotherapy					< 0.001
Yes	5406	65.8	3154	86.9
No	2688	32.7	461	12.7
unknown	127	1.5	14	0.4
Endocrine therapy					0.020
Yes	4969	60.4	2296	63.3
No	2965	36.1	1242	34.2
unknown	287	3.5	91	2.5
Bone metastasis					< 0.001
Yes	5082	61.8	1897	52.3
No	3139	38.2	1732	47.7
Lung metastasis					< 0.001
Yes	1903	23.1	608	16.8
No	6318	76.9	3021	83.2
Liver metastasis					< 0.001
Yes	1600	19.5	493	13.6
No	6621	80.5	3136	86.4
Brain metastasis					< 0.001
Yes	271	3.3	47	1.3
No	7950	96.7	3582	98.7
Distant LN metastasis					< 0.001
Yes	1504	18.3	1022	28.2
No	5860	71.3	2301	63.4
unknown	857	10.4	306	8.4
Other metastasis					0.007
Yes	506	6.2	277	7.6
No	6858	83.4	3046	83.9
unknown	857	10.4	306	8.4
No. of metastatic sites		0.0			< 0.001
1	6110	74.3	3032	83.5
2	1653	20.1	513	14.1
3	388	4.7	79	2.2
4 or more	70	0.9	14	0.4

RT radiotherapy, cT clinical T, cN clinical, ER estrogen receptor, PgR progesterone receptor, HER2 human epidermal growth factor receptor 2, BCS breast conserving surgery, LN lymph node.