The effects of high-dose calcitriol and individualized exercise on bone metabolism in breast cancer survivors on hormonal therapy: a phase II feasibility trial.
Study Goal
The researchers aimed to determine whether individualized exercise, including progressive walking and resistance training, could improve bone metabolism in breast cancer survivors.
Results Summary
Exercise did not improve any bone biomarkers, and compliance with resistance training was sub-optimal (44.4%). The study concluded that exercise was feasible and well tolerated but had no significant effect on bone metabolism.
Population
Breast cancer survivors
Effective Dosage
Progressive walking and resistance training (specific dosage not detailed)
Duration
12 weeks
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
calcitriol (45 micrograms/week) | increase | bone formation | breast cancer survivors | Cohen's d = 0.64 | significantly improved | #1 |
calcitriol (45 micrograms/week) | increase | bone remodeling index | breast cancer survivors | Cohen's d = 0.21 | resulted in a non-significant increase | #2 |
individualized exercise with progressive walking and resistance training | no change | bone biomarkers | breast cancer survivors | - | failed to improve | #3 |
calcitriol (45 micrograms/week) | increase | bone metabolism | breast cancer survivors | - | resulted in a net increase | #4 |
individualized exercise with progressive walking and resistance training | no change | bone metabolism | breast cancer survivors | - | may have led to a lack of effect | #5 |
INTRODUCTION: Cancer treatment-induced bone loss (CTIBL) is a long-term side effect of breast cancer therapy. Both calcitriol and weight-bearing exercise improve bone metabolism for osteoporotic patients, but are unproven in a breast cancer population. We used a novel high-dose calcitriol regimen with an individualized exercise intervention to improve bone metabolism in breast cancer survivors. METHODS: We accrued 41 subjects to this open label, 2 × 2 factorial, randomized feasibility trial. Breast cancer survivors were randomized to receive the following: (1) calcitriol (45 micrograms/week), (2) individualized exercise with progressive walking and resistance training, (3) both, or (4) a daily multivitamin (control condition) for 12 weeks. Primary outcomes included changes in biomarkers of bone formation, bone resorption, and the bone remodeling index, a composite measure of bone formation and resorption. Safety measures included clinical and biochemical adverse events. A main effect analysis was used for these endpoints. RESULTS: Hypercalcemia was limited to three grade I cases with no grade ≥ 2 cases. Among exercisers, 100% engaged in the prescribed aerobic training and 44.4% engaged in the prescribed resistance training. Calcitriol significantly improved bone formation (Cohen's d = 0.64; p < 0.01), resulting in a non-significant increase in the bone remodeling index (Cohen's d = 0.21; p = 31). Exercise failed to improve any of the bone biomarkers. CONCLUSIONS: Both calcitriol and exercise were shown to be feasible and well tolerated. Calcitriol significantly improved bone formation, resulting in a net increase of bone metabolism. Compliance with the exercise intervention was sub-optimal, which may have led to a lack of effect of exercise on bone metabolism.