Conditions: Breast Neoplasms Osteoporosis
Keywords: cancer-treatment related bone loss postmenopausal women breast cancer hormone receptor positive breast cancer adjuvant therapy hormonal therapy bone loss bisphosphonates ZFAST Letrozole Zoledronic Acid US32
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 602
Healthy volunteers: no

Brief summary:
This protocol is designed to compare the effect on bone of Zoledronic Acid 4 mg every 6 months when given upfront versus delayed start (based on a post-baseline BMD T- Score below -2.0 SD at either the lumbar spine or total hip, or any clinical fracture unrelated to trauma, or an asymptomatic fracture discovered at the month 36 scheduled visit) in stage I-IIIb postmenopausal women with hormone receptor positive breast cancer who will receive Letrozole 2.5 mg daily as an adjuvant therapy.

Detailed description:

Arms:
arm 1: Participants in the upfront arm received zoledronate 4 mg i.v. on Day 1 and every 6 months until disease progression (recurrence) or the end of study. Participants also received Letrozole 2.5 daily plus calcium (1000-1200 mg) and vitamin D (400-800 IU) daily. arm 2: In lieu of a placebo arm, which was considered unethical for this trial, a delayed start arm was used. Participants who met certain clinical criteria indicating risk of lumbar spine or total hip fracture, or experienced clinical fracture unrelated to trauma or any asymptomatic fracture discovered at the Month 36 scheduled visit, were started on zoledronate 4 mg i.v. and for every 6 months until disease progression (recurrence) or end of study. Participants also received Letrozole 2.5 daily plus calcium (1000-1200 mg) and vitamin D (400-800 IU) daily.

Interventions: intervention 1: Zoledronic Acid intervention 2: Letrozole
Intervention descriptions: intervention 1: Participants received Zoledronate 4 mg IV 15-minute infusion every 6 months. intervention 2: Participants received Letrozole 2.5 mg daily.

Protocol document: