Table 2.

Tumor characteristics and treatment factors

Covariates	Category	BCS	OBS	Total
		n = 631	n = 96	n = 727
		Column percent*
Tumor size	T1 ≤ 20 mm	84.0	62.5	81.2
	T2 21–50 mm	15.7	34.4	18.2
	T3 ≥ 50 mm	0.3	0.0	0.3
Lumpectomy size (cm3)	< 50	20.0	15.6	19.4
	50–99	30.7	26.0	30.1
	100–199	33.0	32.3	32.9
	≥ 200	14.9	21.9	15.8
Tumor location	Upper lateral	37.9	40.6	38.2
	Upper medial	14.6	8.3	13.8
	Lower lateral	8.9	9.4	8.9
	Lower medial	7.0	6.3	6.9
	Central	6.2	15.6	7.4
	Overlapping regions	23.8	19.8	23.2
Axillary dissection	No	66.2	52.1	64.4
	Yes	33.8	44.8	35.2
Radiotherapy	No	4.4	2.1	4.1
	Yes	95.6	97.9	95.9
Chemotherapy	No	58.6	49.0	57.4
	Yes	41.4	51.0	42.6
Endocrine therapy	No	42.3	34.4	41.3
	Yes	57.7	65.6	58.7
Immune therapy	No	91.1	89.6	90.9
	Yes	8.9	10.4	9.1

*Column percent does not always add up to 100 as missing data are not shown