Implications of the 21-gene recurrence score assay (Oncotype DX) on adjuvant treatment decisions in ER-positive early-stage breast cancer patients: experience of Kuwait Cancer Control Center

Table 2 Clinicopathological characteristics of patients according to their initially suggested treatment

			Initially proposed treatment groups				p value
	Whole group		ET		CET		p value
	n	%	n	%	n	%
All patients	100	100	54	54	46	46
Age
Age ≤ 50 years	51	51	27	50	24	52.2	0.829
Age > 50 years	49	49	27	50	22	47.8	0.829
Menstrual status
Premenopausal	59	59	32	59.3	27	58.7	0.955
Postmenopausal	41	41	22	40.7	19	41.3	0.955
Tumor histological grade
Grade 1	15	15	10	18.5	5	10.9	0.004
Grade 2	64	64	39	72.2	25	54.3
Grade 3	17	17	3	5.6	14	30.4
Grade (unknown)	4	4	2	3.7	2	4.3
Ki-67 index
Ki-67 ≤ 15	51	51	33	61.1	18	39.1	< 0.001
Ki-67 > 15	38	38	10	18.5	28	60.9	< 0.001
Ki-67 (unknown)	11	11	11	20.4	0	0
Tumor type
IDC	94	94	53	98.1	41	89.1	0.060
ILC	6	6	1	1.9	5	10.9	0.060
Primary tumor surgical approach
WLE	78	78	43	79.6	35	76.1	.424
Mastectomy	22	22	11	20.4	11	23.9	.424
Axillary surgical management
SLN	84	84	46	85.2	38	82.6	0.349
Axillary clearance	16	16	8	14.8	8	17.4	0.349
pT stage
pT1	39	39	29	53.7	10	21.7	< 0.001
pT2	55	55	25	46.3	30	65.2
pT3	6	6	0	0	6	13
pN stage
pN0	76	76	49	90.7	27	58.7	0.001
pN1mic	10	10	5	9.3	5	10.9
pN1	14	14	0	0	14	30.4
Lymphovascular invasion
LVI+	17	17	3	5.6	14	30.4	0.001
LVI−	78	78	50	92.6	28	60.9	0.001
LVI-unknown	5	5	1	1.9	4	8.7
Luminal tumor type
Luminal A	54	54	40	74.1	14	30.4	< 0.001
Luminal B	46	46	14	25.9	32	69.6	< 0.001
Estrogen receptor positivity percentage
ER ≥ 90%	88	88	48	88.9	40	87.0	0.295
ER 30–80	12	12	6	11.1	6	13.0	0.295
Progesterone receptor positivity percentage
PR ≥ 90%	48	48	28	51.9	20	43.5	0.406
PR 0–85%	52	52	26	48.1	26	56.5	0.406

IDC invasive duct carcinoma, ILC invasive lobular carcinoma, WLE wide local excision, SLN sentinel lymph node