Table 2.

Comparison of the clinical and treatment characteristics across treatment cohorts of interest.

	Axillary Surgery and Radiation Cohorts					F-statistic P-value
	No Axillary Surgery	SLNB without RLNR	SLNB with RLNR	ALND without RLNR	ALND with RLNR
Clinical Factor	No. of patients(%)†	No. of patients(%)†	No. of patients(%)†	No. of patients(%)†	No. of patients(%)†
Age at diagnosis, years
Median (range)	58.5 (34.1, 87)	56.8 (27, 87.9)	51.1 (24.4, 79.5)	50.4 (28.5, 83.6)	49.6 (24.8, 83.7)	< 0.001
BMI at diagnosis
Median (range)	27 (19, 47.2)	26.3 (17, 58.9)	25.1 (17.5, 47.5)	26.2 (17.9, 44.5)	26.9 (16.5, 58.4)	0.2592
Tumor type
DCIS	118	97	0	1	3	< 0.001
IBC	81	1285	138	146	397
Invasive tumor size, cm* Median (range)
Median (range)	0.75 (0.05, 7)	1.1 (0.01, 10.5)	1.5 (0.15, 13)	1.5 (0.1, 16)	2 (0.01, 15)	< 0.001
Lymph node characteristics median (range)
No. LNs removed	n/a	2 (1, 50)	2 (1, 18)	15 (2, 35)	17 (2, 64)	< 0.001
No. of positive LNs		0 (0, 3)	1 (0, 8)	1 (0, 13)	3 (0, 52)
Neoadjuvant chemotherapy
Yes	28	47	32	37	172	< 0.001
No	171	1335	106	110	228
Adjuvant chemotherapy
Yes	14	345	90	88	250	< 0.001
No	185	1037	48	59	150
Hormonal therapy
Yes	106	1046	104	105	285	< 0.001
No	93	336	34	42	115

Abbreviations: No., number; BMI, body mass index; SNB, sentinel lymph node biopsy; ALND, axillary lymph node dissection; RLNR, regional lymph node radiation; LN, lymph node; RT, radiation therapy; DCIS, ductal carcinoma in situ; IBC, invasive breast cancer

^*this does not include tumor size for patients who received neoadjuvant chemotherapy

^†or mean (range) where specified