Table 1.

Baseline characteristics.

	n = 176		%
Median age (y)	59 (30–87)1
≧ 60	87		49.4
< 60	89		50.6
ER status
positive	144		81.8
negative	32		18.2
PgR status
positive	111		63.1
negative	65		36.9
HER2 status
positive	31		17.6
negative	145		82.4
Metastases
Bone only	53		30.1
Presence of other metastases	123		69.9
Bone metastases
Localized	54		30.7
Multiple	122		69.3
Prior therapy
Hormonal therapy
yes	27		15.3
no	149		84.7
Chemotherapy
yes	27		15.3
no	149		84.7
Combined therapy
Hormonal therapy
yes	127		72.2
no	49		27.8
Chemotherapy
yes	137		77.8
no	39		22.2
The median period from diagnosis of BC to the start of ZA therapy (month)	55.5 (0–349)2
Prior to SSE
yes	27	15.3
no	149	84.7
The median period of ZA therapy (month)	15.5 (0.4–56.1)2

Abbreviations: ER estrogen receptor; PgR progesterone receptor; HER2 human epidermal growth factor 2 receptor, BC breast cancer, ZA zoledronic acid.

¹mean (range).

²median(range).