title: Survival benefit of zoledronic Acid in postmenopausal breast cancer patients receiving aromatase inhibitors.
abstract: OBJECTIVE
  A growing body of evidence indicates that zoledronic acid (ZA) can improve the clinical outcome in patients with breast cancer and low estrogen levels. In the present study, we aimed to investigate the survival benefit of ZA administration in postmenopausal Korean women with breast cancer who were also receiving aromatase inhibitors.
  
  
  METHODS
  Between January 2004 and December 2010, 235 postmenopausal breast cancer patients undergoing aromatase inhibitor therapy were investigated. All patients were postmenopausal, as confirmed by laboratory tests. Of these patients, 77 received adjuvant upfront ZA for at least 1 year in addition to conventional adjuvant treatment. The remaining 158 patients never received ZA and were treated according to the St. Gallen guidelines.
  
  
  RESULTS
  The baseline characteristics for ZA treatment were not different between the two groups. The median follow-up time was 62 months, and the patients who received ZA in addition to aromatase inhibitors showed a better recurrence-free survival compared to those who received aromatase inhibitors alone (p=0.035). On multivariate analysis, the patients who received ZA showed a better recurrence-free survival independent of the tumor size, nodal status, progesterone receptor, and histological grade. For this model, Harrell c index was 0.743. The hazard ratio of ZA use for recurrence-free survival was 0.12 (95% confidence interval, 0.01-0.99).
  
  
  CONCLUSIONS
  Our findings suggest that upfront use of ZA as part of adjuvant treatment can offer a survival benefit to postmenopausal breast cancer patients receiving aromatase inhibitor treatment.
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Sung Gwe
authors.initials: SG
authors.lastname: Ahn
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Sung Hyun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hak Min
authors.initials: HM
authors.lastname: Lee
authors.affiliation: Department of Surgery, Eulji University College of Medicine, Seoul, Korea.
authors.forename: Seung Ah
authors.initials: SA
authors.lastname: Lee
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Joon
authors.initials: J
authors.lastname: Jeong
keywords: Aromatase inhibitors; Breast neoplasms; Postmenopause; Zoledronic acid