• Therapy for Palliation of Bony Metastases

• Physical Characteristics of ⁸⁹Sr

  • prepared by ⁸⁸Sr(n,g)⁸⁹Sr
    

  • t_1/2 = 50.5 days
    

  • type of decay: b-
    

  • maximum energy: 1.463 MeV, 100%
    

  • range of b- in tissue: 8 mm
    

• Advances in Cancer Therapy

  • Longer survival in many cancers
    
  • Better pain control medication
    
  • More aggressive radiotherapy

• Bony Metastases in Breast and Prostate Cancer
  • Prostate cancer 50% of patients have bone disease at time of diagnosis
    
  • Breast cancer 15% of stage III patients and 50% of Stage IV patients have bone metastases
    

• Therapeutic Approaches to Bone Pain

  • NSAIDs
    
  • Chemotherapy
    
  • Hormonal Therapy
    
  • External Beam Radiation
    
  • Narcotic Therapy
    
  • Radiopharmaceutical Therapy

    • Historical Approach to Radionuclide Therapy
      

    • Na₃³²PO₄ in 1940’s
      
    • ⁸⁹SrCl₂ in late 1980’s
      
    • ¹⁵³Sm EDTMP in late 1990’s
      

    • ³²P-Na₃PO₄

• 1. long history
  
• 2. 60-75% response rate in literature
  
• 3. significant marrow depression- end point is toxicity
  
• 4. infrequently used

⁸⁹Sr strontium chloride therapy for palliation of bony metastases

1. Indications: bone pain caused by any primary malignancy

• metastatic to bone. Implication: Must have a bone scan positive for metastases. Most commonly used for breast and prostate cancer

2. Palliative, not curative

3. Bone localizer; calcium analog with distribution very similar to ^99mTc-MDP

4. 80% Response rate overall

5. Ratio of metastatic lesions to normal bone = 5:1

6. Ratio of metastatic lesions to marrow = 10:1

7. Retention of ⁸⁹Sr in metastases longer than in bone

8. No reported adverse reactions

9. 30-50% of patients have measurable decrease in WBC and platelets

10. Recovery begins at about 6 weeks

11. Flare phenomenon often prognostic indicator of successful treatment

Typical Dose: ⁸⁹Sr chloride

4 mCi given by IV Injection for intractable bone pain from prostate, breast cancer or other primary malignancy