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

Table 3 Anatomical distribution of second bone metastasis according to histological subtypes, n (%)

Second bone metastasis	Luminal A (n = 82)	Luminal B (n = 12)	Triple neg (n = 8)	HER 2 enrich (n = 5)	P value
Without bone progression	16/82 (19.5)	3/12 (25)	3/8 (37.5)	1/5 (20)	0.68
Skull bones	7/82 (9)	0	0	0	0.50
Scapula and clavicle	6/82 (7)	1/12 (8)	1/8 (12.5)	0	0.36
Sternum	7/82 (9)	0	0	0	0.50
Humerus	10/82 (12.5)	2/12 (17)	2/8 (25)	0	0.60
Ribs	28/82 (35)	2/12 (17)	0	1/5 (20)	0.13
Cervical vertebra	19/82 (24)	3/12 (25)	1/8 (12.5)	1/5 (20)	0.90
Thoracic vertebra	35/82 (44)	3/12 (25)	2/8 (25)	2/5 (40)	0.50
Lumbar vertebra	28/82 (35)	6/12 (50)	2/8 (25)	0	0.24
Sacrum	17/82 (21)	3/12 (25)	0	1/5 (20)	0.53
Pelvic bones (ilium, ischium, pubis)	31/82 (38)	7/12 (58)	0	3/5 (60)	0.046
Femoral head and neck	25/82 (31)	2/12 (17)	3/8 (37.5)	1/5 (20)	0.68
Femoral shaft and distal femur	24/82 (30)	2/12 (17)	2/8 (25)	1/5 (20)	0.77