Safety and Efficacy of Long-Term Zoledronic Acid in Advanced Breast Cancer with Bone Metastasis in South China

Table 3

Number of cases with SREs in ABC with bone metastasis according to the initiation of ZA.

SRE	Group A (ZA 6–24 months); n = 293	Group B (ZA > 24 months); n = 273	value
No	190 (64.8%)	135 (49.4%)	<0.001
Yes	103 (35.2%)	138 (50.6%)

SRE: skeletal-related event, ABC: advanced breast cancer, and ZA: zoledronic acid. All cases without SRE before the initiation of ZA were divided into subgroups by the occurrence of SRE after the initiation of ZA. The difference between subgroups was compared by the Pearson chi-square test.