How often should a DEXA (Dual-Energy X-ray Absorptiometry) scan be performed in a 59-year-old female with a history of left breast atypical ductal hyperplasia, status post excision, currently on Anastrazole (anastrozole)?

DEXA Scan Frequency for a 59-Year-Old Female with Atypical Ductal Hyperplasia on Anastrozole

A DEXA scan should be performed at baseline before starting anastrozole therapy, followed by repeat scans every 2 years for this 59-year-old female with history of left breast atypical ductal hyperplasia who is currently on anastrozole. 1

Rationale for DEXA Scan Monitoring

Baseline Assessment

• Prior to initiating an aromatase inhibitor like anastrozole, clinicians should evaluate patients for baseline fracture risk and measure bone mineral density 1
• This establishes a reference point to monitor potential bone loss associated with anastrozole therapy

Follow-up Schedule

• DEXA scans should be repeated every 2 years or as clinically indicated 1
• More frequent monitoring (annually) is not recommended as bone mineral density assessment should not be conducted more than once per year 1

Risk Factors for Bone Loss with Anastrozole

Anastrozole significantly impacts bone health through several mechanisms:

• Patients receiving anastrozole have an increased incidence of all fractures (specifically spine, hip, and wrist) compared to patients on tamoxifen (10% vs 7%) 2
• Anastrozole causes a mean decrease in both lumbar spine and total hip bone mineral density 2
• The risk of bone loss continues throughout treatment, with cumulative incidence of first fractures being higher in anastrozole groups (15%) compared to tamoxifen groups (11%) 2

Management Recommendations

Bone Health Protection

• All patients on anastrozole should be encouraged to:
  • Take adequate calcium and vitamin D supplements
  • Engage in regular weight-bearing exercises
  • Minimize fall risk
  • Maintain bone-healthy lifestyle (tobacco cessation, limiting alcohol) 1

Intervention Thresholds

Consider bone-modifying agents if:

• FRAX calculation shows 10-year risk of hip fracture ≥3%, or 10-year risk of non-hip fracture ≥20%
• DEXA demonstrates osteoporosis or significant osteopenia with additional risk factors 1

Special Considerations

• Anastrozole should be used with caution in women with moderate bone mineral density loss 1
• Consider bone-protective agents such as bisphosphonates and RANKL inhibitors for those at higher risk 1
• A history of severe osteoporosis (T score <-4 or more than two vertebral fractures) is a relative contraindication for anastrozole use 1

Monitoring Algorithm

1. Baseline assessment: DEXA scan before starting anastrozole
2. Regular follow-up: Repeat DEXA every 2 years
3. Risk assessment: Calculate FRAX score at each evaluation
4. Intervention: Initiate bone-modifying agents if thresholds are met
5. Continued monitoring: Maintain regular DEXA scans every 2 years throughout anastrozole treatment

Common Pitfalls to Avoid

• Inadequate monitoring: A study found that only 34.5% of older Medicare beneficiaries with breast cancer treated with AIs had both a baseline and at least one follow-up DEXA scan during a 3-year period 3
• Overscreening: Performing DEXA scans more frequently than annually provides minimal additional information and increases healthcare costs 1
• Failure to implement preventive measures: Not providing calcium/vitamin D supplementation and exercise recommendations alongside monitoring

By following this evidence-based approach to DEXA scan monitoring, you can effectively manage this patient's bone health while she continues her necessary anastrozole therapy for breast cancer risk reduction.