When should dexa (Dual-Energy X-ray Absorptiometry) scans be started in women after an oophorectomy at age 48?

DEXA Scan Timing After Oophorectomy at Age 48

Women who undergo oophorectomy at age 48 should have a baseline DEXA scan immediately following surgery, with follow-up scans every 1-2 years due to the rapid bone loss that occurs after surgical menopause. 1, 2

Rationale for Immediate DEXA Scanning

• Surgical menopause from oophorectomy causes rapid and significant bone loss, with studies showing a 10.7% decrease in bone mineral density (BMD) in the first year after surgery 3
• Women who undergo risk-reducing bilateral salpingo-oophorectomy (RRBSO) before age 50 experience substantial loss of bone density and bone strength compared to those who retain their ovaries 2
• Even with hormone therapy (HT), there is still a modest 2.3% loss in lumbar spine BMD within 24 months after premenopausal oophorectomy 1

Monitoring Schedule

• After baseline DEXA scan, follow-up scans should be performed every 1-2 years for women with oophorectomy before natural menopause 4, 5
• This more frequent monitoring schedule (compared to the standard 2-3 years) is justified by the accelerated bone loss in the first two years post-oophorectomy (10.7% in first year, 5.7% in second year) 3
• Women not using hormone therapy should be monitored more closely, as they experience greater bone loss at the lumbar spine (5.8%), total hip (5.2%), and femoral neck (6.0%) within 24 months 1

Risk Assessment and Management

• Oophorectomy before natural menopause is considered a significant risk factor requiring earlier DEXA screening 4, 5
• When risk factors for osteoporotic fracture are present, bone mineral density should be evaluated to quantify fracture risk, with DXA of total spine, hip, and femoral neck being the preferred assessment 6
• The FRAX tool should be used to calculate 10-year fracture risk, with treatment thresholds including:
  • 10-year risk of hip fracture ≥3% 6
  • 10-year risk of major osteoporotic fracture ≥20% 6
  • BMD showing osteoporosis or significant osteopenia with additional risk factors 6

Preventive Measures

• All patients should be counseled on calcium and vitamin D intake, weight-bearing exercises, minimizing fall risk, and bone-healthy lifestyle behaviors including tobacco cessation and limiting alcohol consumption 6
• Consider hormone therapy to mitigate bone loss, as studies show HT significantly reduces bone loss at both spine and hip compared to no HT use 1, 2
• If bone density results do not indicate osteoporosis and FRAX calculation does not exceed treatment thresholds, repeat DEXA in 1-2 years 6

Common Pitfalls and Considerations

• Many women with surgical menopause are not adequately screened for bone loss, with studies showing only 44% of women having at least one DXA scan following oophorectomy 7
• Bone loss may reach osteoporotic levels (BMD < 0.767 g/cm²) approximately 12 years after oophorectomy if not properly managed 3
• Hormone therapy alleviates but does not fully prevent spinal bone loss following surgical menopause 1, 2
• Bone resorption markers increase significantly in the first year after oophorectomy, while bone formation markers peak in the second year, explaining the pattern of maximal bone loss in the first year 3