Table 2. Patient characteristics of the permanent histology and one-step nucleic acid amplification (OSNA) assay cohorts.

	Histology		OSNA
Characteristics	No.	%	No.	%	P-value
No. of patients	64	100	119	100
Age					0.13
Median (range)	56 (39–81)		53 (27–86)
Menstrual status					0.079
Premenopausal	21	32.8	55	46.2
Postmenopausal	43	67.2	64	53.8
Breast surgery					0.25
Conservative	32	50.0	70	58.8
Mastectomy	32	50.0	49	41.2
SN identification					0.84
Radioisotope alone	10	15.6	20	16.8
Radioisotope plus dye	54	84.4	99	83.2
No. of SNs removed					0.92
Median (range)	2 (1–8)		2 (1–10)
Interquartile range	1, 3		1, 3
No. of positive SNs					0.61
1	53	82.8	91	76.5
2	8	12.5	20	16.8
⩾3	3	4.7	8	6.7
SN status					0.28
(+)	21	32.8	50	42.0
(+I)	15	23.4	18	15.1
(++)	28	43.8	51	42.9
AJCC SN stage					0.46
pN1mi(sn)	21	32.8	50	42.0
pN1a(sn)	41	64.1	65	54.6
pN2a(sn)	2	3.1	4	3.4
Axillary surgery					0.13
Level I	10	15.6	30	25.2
Level II or III	54	84.4	89	74.8
No. of non-SNs removed					0.11
Median (range)	17 (8–40)		15 (6–33)
Interquartile range	13, 21		13, 19
Pathological T classification					0.57
pT1mi	2	3.1	4	3.4
pT1a	2	3.1	10	8.4
pT1b	8	12.5	20	16.8
pT1c	33	51.6	56	47.1
pT2	19	29.7	29	24.4
Histological type					0.59
Ductal	57	89.1	110	92.4
Lobular	2	3.1	4	3.4
Special types	5	7.8	5	4.2
Nuclear grade					0.22
1	19	29.7	54	45.4
2	27	42.2	39	32.8
3	11	17.2	17	14.3
Lobular/special type	7	10.9	9	7.6
Lymphovascular invasion					0.23
−	29	45.3	65	54.6
+	35	54.7	54	45.4
Fat infiltration					0.86
−	8	12.5	16	13.4
+	56	87.5	103	86.6
Oestrogen receptor status					0.43
−	12	18.8	17	14.3
+	52	81.3	102	85.7
Progesterone receptor status					0.97
−	24	37.5	45	37.8
+	40	62.5	74	62.2
HER2 status					0.53
−	55	85.9	106	89.1
+	9	14.1	13	10.9

Abbreviations: AJCC=American Joint Committee on Cancer; HER2=human epidermal growth factor receptor-2; (+I)=positive with reaction inhibited; SN=sentinel lymph node.