Anatomical distribution of bone metastases in stage IV breast cancer: According to histological subtype

Table 2 Anatomical distribution of first bone metastasis according to histological subtypes, n (%)

First bone metastasis	Luminal A (n = 82)	Luminal B (n = 12)	Triple neg (n = 8)	HER 2 enrich (n = 5)	P value
Skull bones	3/82 (3.7)	0	1/8 (12.5)	0	0.5
Scapula and clavicle	3/82 (3.7)	1/12 (8.3)	3/8 (37.5)	0	0.003
Sternum	7/82 (8.5)	2/12 (17)	1/8 (12.5)	2/5 (40)	0.16
Humerus	14/82 (17)	2/12 (17)	1/8 (12.5)	0	0.77
Ribs	24/82 (30)	2/12 (17)	1/8 (12.5)	4/5 (80)	0.041
Cervical vertebra	12/82 (15)	3/12 (25)	1/8 (12.5)	0	0.60
Thoracic vertebra	36/82 (44)	5/12 (45.5)	2/8 (25)	3/5 (60)	0.64
Lumbar vertebra	38/82 (46)	7/12 (58)	3/8 (37.5)	2/5 (40)	0.79
Sacrum	18/82 (22)	1/12 (8)	1/8 (12.5)	1/5 (20)	0.68
Pelvic bones (ilium, ischium, pubis)	43/82 (52)	5/12 (42)	5/8 (62.5)	3/5 (60)	0.80
Femoral head and neck	21/82 (26)	4/12 (33)	2/8 (25)	3/5 (60)	0.39
Femoral shaft and distal femur	20/82 (25)	3/12 (25)	2/8 (25)	3/5 (60)	0.38