Managing Osteoporosis in Patients Taking Exemestane

Introduction to Osteoporosis Management

The American Society of Clinical Oncology recommends that all postmenopausal women taking exemestane require baseline bone mineral density assessment, periodic monitoring, mandatory calcium (1,000-1,200 mg/day) and vitamin D (800-1,000 IU/day) supplementation, and consideration of bisphosphonates or denosumab if osteoporosis develops or fracture risk is elevated 1, 2

Exemestane causes significant, clinically meaningful bone loss that exceeds normal age-related decline, with lumbar spine BMD decreases by 2.4-3.5% at 2 years compared to 0.5-2.4% with placebo 3
Total hip BMD decreases by 1.8-4.6% at 2 years compared to 0.6-2.6% with placebo 3
Femoral neck BMD decreases by 2.4-4.2% at 2 years 3
Cortical thickness at distal radius and tibia decreases by approximately 7-8% at 2 years 3

Clinicians must evaluate baseline fracture risk using clinical assessment 2, 4
Measure bone mineral density with central/axial DXA at lumbar spine, total hip, and femoral neck 1, 2
Exclude severe osteoporosis (T-score < -4 or >2 vertebral fractures), which is a relative contraindication to exemestane 2

Repeat DXA every 2 years or more frequently if BMD is near treatment threshold 1
Do not perform DXA more frequently than annually 1
Continue monitoring throughout the treatment duration 3, 5

Calcium supplementation: 1,000-1,200 mg/day 1, 2
Vitamin D supplementation: 800-1,000 IU/day (higher doses if deficient) 1, 2
Exercise program including balance training, flexibility exercises, endurance exercise, and resistance/progressive strengthening 1
Smoking cessation and alcohol limitation 1

Initiate bisphosphonates or denosumab if T-score ≤ -2.5 at any site (lumbar spine, total hip, or femoral neck) 1
Initiate bisphosphonates or denosumab if 10-year fracture probability ≥20% for major osteoporotic fracture using FRAX 1
Initiate bisphosphonates or denosumab if 10-year fracture probability ≥3% for hip fracture using FRAX 1
Options for bone-modifying agents include oral bisphosphonates (e.g., alendronate, risedronate) 1
Options for bone-modifying agents include intravenous bisphosphonates (e.g., zoledronic acid) 1
Options for bone-modifying agents include subcutaneous denosumab at osteoporosis-indicated dosing 1

Consider alternative endocrine therapies that do not reduce bone density, such as tamoxifen or raloxifene (if appropriate for the clinical indication) 2

Do not start exemestane without baseline BMD assessment 2
Do not assume calcium and vitamin D alone are sufficient to prevent bone loss 3
Do not wait for fractures to occur before initiating bone-protective therapy 1
Do not use exemestane in patients with severe baseline osteoporosis without concurrent aggressive bone protection 2