Breast cancer risk factors in relation to molecular subtypes in breast cancer patients from Kenya

Sayed, Shahin; Fan, Shaoqi; Moloo, Zahir; Wasike, Ronald; Bird, Peter; Saleh, Mansoor; Shaikh, Asim Jamal; Figueroa, Jonine D.; Naidoo, Richard; Makokha, Francis W.; Gardner, Kevin; Oigara, Raymond; Njoroge, Faith Wambui; Magangane, Pumza; Mutebi, Miriam; Chauhan, Rajendra; Mwanzi, Sitna; Govender, Dhirendra; Yang, Xiaohong R.

doi:10.1186/s13058-021-01446-3

Breast Cancer Research

Table 2 Distributions of tumor characteristics in Kenyan breast cancer patients, overall and by hospitals (N=838)

From: Breast cancer risk factors in relation to molecular subtypes in breast cancer patients from Kenya

Tumor characteristic	Overall (n=838)		Hospitals
	Overall (n=838)		AKU (n=350, 42%)		Kijabe (n=105, 13%)		Nyeri (n=110, 13%)		St Mary’s (n=122, 15%)		Others (n=151, 18%)
	N	%	N	%	N	%	N	%	N	%	N	%	P*
*Tumor subtypes*
ER status
Negative	256	30.6	101	28.9	25	23.8	45	40.9	32	26.2	53	35.1	0.029
Positive	582	69.5	249	71.1	80	76.2	65	59.1	90	73.8	98	64.9
PR status
Negative	340	40.6	138	39.4	36	34.3	50	45.5	48	39.3	68	45.0	0.36
Positive	498	59.4	212	60.6	69	65.7	60	54.5	74	60.7	83	55.0
HER2 status
Negative	596	72.6	246	71.3	75	72.1	81	76.4	91	74.6	103	71.5	0.84
Positive	225	27.4	99	28.7	29	27.9	25	23.6	31	25.4	41	28.5
Missing	17		5		1		4		0		7
Tumor molecular subtype
Luminal A^a	286	34.8	121	35.1	46	44.2	37	34.9	40	32.8	42	29.2	0.080
Luminal B	294	35.8	127	36.8	33	31.7	26	24.5	52	42.6	56	38.9
HER2-enriched	88	10.7	37	10.7	11	10.6	14	13.2	12	9.8	14	9.7
Triple negative	153	18.6	60	17.4	14	13.5	29	27.4	18	14.8	32	22.2
Missing	17		5		1		4		0		7
Luminal A^a	286	36.9	121	36.7	46	48.9	37	37.4	40	33.9	42	31.1	0.094
Luminal B - HER2^-	157	20.2	65	19.7	15	16.0	15	15.2	33	28.0	29	21.5
Luminal B - HER2⁺	137	17.7	62	18.8	18	19.1	11	11.1	19	16.1	27	20.0
HER2-enriched	88	11.3	37	11.2	11	11.7	14	14.1	12	10.2	14	10.4
Core-basal like	57	7.3	24	7.3	2	2.1	13	13.1	7	5.9	11	8.1
Five negative	51	6.6	20	6.4	2	2.1	9	9.1	7	5.9	12	8.9
Missing	62^b		20		11		11		4		16
*Tumor pathology*
Surgery
Core biopsy only	435	51.9	157	44.9	26	24.8	46	41.8	73	59.8	133	88.1	< 0.0001
Lumpectomy or mastectomy	403	48.1	193	55.1	79	75.2	64	58.2	49	40.2	18	11.9
Tumor size (cm)
< 2	41	7.6	29	13.1	8	8.1	2	2.3	1	1.9	1	1.3	< 0.0001
2–< 5	287	53.5	134	60.4	53	53.5	39	44.8	26	50.0	35	45.5
≥ 5	209	38.9	59	26.6	38	38.4	46	52.9	25	48.1	41	53.3
Missing^c	301		128		6		23		70		74
Tumor overall grade
Grade 1 (low)	35	5.0	20	7.3	4	4.4	6	5.7	2	1.7	3	2.8	0.17
Grade 2 (intermediate)	319	45.9	130	47.3	34	37.8	44	41.5	59	50.9	52	48.2
Grade 3 (high)	341	49.1	125	45.5	52	57.8	56	52.8	55	47.4	53	49.1
Missing/not applicable	143		75		15		4		6		43
Lymphovascular invasion
No	326	38.9	139	39.7	30	28.6	34	30.9	47	38.5	76	50.3	0.0029
Yes	512	61.1	211	60.3	75	71.4	76	69.1	75	61.5	75	49.7
Among cases with lumpectomy or mastectomy (n=403):
Tumor stage
Stage 0, i	30	8.2	21	12.1	2	2.6	6	10.3	1	2.4	0	0.0	0.0040
Stage ii	154	42.3	85	49.1	30	39.5	20	34.5	12	29.3	7	43.8
Stage iii, iv	180	49.5	67	38.7	44	57.9	32	55.2	28	68.3	9	56.3
Missing	39		20		3		6		8		2
Lymph nodes with metastasis
No	162	40.2	89	46.1	23	29.1	22	34.4	20	40.8	8	44.4	0.96
Yes	241	59.8	104	53.9	56	70.9	42	65.6	29	59.2	10	55.6
Extranodal extension
No	244	60.6	132	68.4	39	49.4	35	54.7	26	53.1	12	66.7	0.022
Yes	159	39.5	61	31.6	40	50.6	29	45.3	23	46.9	6	33.3

* P values were computed from chi-square test except where noted. P values less than 0.05 are shown in bold font. ^a Seventy-four cases, who had missing data for both ki67 and tumor grade, were grouped into the subcategory “Luminal A” in tumor molecular subtype. ^bSixty-two cases whose tumor molecular subtype cannot be determined: 17 cases are due to their missing HER2 status; the other 45 cases are due to their missing CK5/6 and EGFR status. ^c Ninety-eight percent of missingness are from cases with core biopsy only. AKU, Aga Khan University; CK5/6, cytokeratin 5/6; EGFR, epidermal growth factor receptor; ER, estrogen receptor; HER2, human epidermal growth factor receptor-2; PR, progesterone receptor

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