Table 2.

Covariate Incidence in the No Axillary Lymph Node Dissection (ALND), No Mastectomy, No Radiation (Observation) Group; the ALND Only Group; the ALND and Mastectomy With or Without Radiation (Mastectomy) Group, and the ALND and Radiation Only (Breast-Conserving Therapy) Group

	Observation (n = 94)			ALND Only (n = 126)			Mastectomy Group (n = 268)			BCT Group (n = 202)
Variable	No.		%	No.		%	No.		%	No.		%	P
Age, y													.11
<50	17		18.1	22		17.5	73		27.2	52		25.7
≥50	77		81.9	103		81.7	195		72.8	150		74.3
Median		62			62			59			57
Grade													.39
1	0		0	0		0	5		1.9	1		0.5
2	5		5.3	8		6.3	19		7.1	10		5
3	26		27.7	45		35.7	86		32.1	71		35.1
Unknown	63		67	73		57.9	158		59	120		59.4
ER status													.64
Positive	37		39.4	33		26.2	96		81			40.1
Negative	30		31.9	47		37.3	79		80		39.6
Unknown	27		28.7	46		36.5	93		41		20.3
No. of lymph nodes resected													.04
1−9	NA			39		31	55		20.5			25.7
≥10	NA			56		44.4	153		57.1		56.9
No. of lymph nodes positive													.04
1−9	NA			88		69.8	167		62.3	133		66.8
≥10	NA			9		7.1	43		16	34		16.8
Year diagnosed													.17
1983–1997	29		30.9	43		34.1	108		40.3	64		31.7
1998–2006	65		69.1	83		65.9	160		59.7	138		68.3

BCT indicates breast-conserving therapy; ER, estrogen receptor.