Conditions: Breast Cancer
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 160
Healthy volunteers: no

Brief summary:
The primary purpose is to determine if high dose vitamin D3 reduces the incidence of musculoskeletal symptoms associated with the aromatase inhibitor letrozole in women with early stage breast cancer and low serum vitamin D levels.

Detailed description:
The primary hypothesis is that high dose vitamin D3 plus standard dose vitamin D3 prevents the worsening of musculoskeletal symptoms when compared to a standard dose vitamin D3 treatment. This protocol will examine the relationship between vitamin D levels (25-hydroxyvitamin D) and various quality of life measures in women being treated with letrozole as standard care for early stage breast cancer. All subjects received letrozole and a standard dose of vitamin D3 (600 IU daily). Randomization was between high dose vitamin D3 (30,000 IU once per week) vs. a blinded, matched placebo,

Arms:
arm 1: High Dose Vitamin D3 capsule (3 x 10,000 IU capsules weekly). All subjects also received standard dose vitamin D3 (600 IU daily) and letrozole (2.5 mg daily). arm 2: Placebo matched for High Dose Vitamin D3 capsules. All subjects also received standard dose vitamin D3 (600 IU daily) and letrozole (2.5 mg daily).

Interventions: intervention 1: High Dose Vitamin D intervention 2: Placebo intervention 3: Standard Dose Vitamin D3 intervention 4: Letrozole 2.5mg
Intervention descriptions: intervention 1: High Dose Vitamin D3 (3 capsules of 10,000 IU) weekly for 24 weeks. intervention 2: Placebo comparator intervention 3: Standard Dose Vitamin D3 (600 IU of vitamin D3 daily) intervention 4: All subjects received letrozole as standard of care.

Protocol document: