Includes summary of article:
Metastatic Bone Disease: Diagnosis, Evaluation, and Treatment
Biermann JS, Holt GE, Lewis VO, Schwartz HS, Yaszemski MJ. J Bone Joint Surg AM. 2009;91:1518-30.
Carcinomas that commonly spread to bone: Breast, Lung, Thyroid, Kidney, Prostate. Common sites: spine>proximal femur>humerus
Prognosis (median survivals): thyroid (48 months), prostate (40 months), breast (24 months), kidney (variable, 6 months), lung (6 months).
Must get plain radiographs – note anatomic site of tumor, zone of transition, internal characteristics of lesion.
Aggressive features of lesion may include: >5 cm in diameter, interruption of cortex, periosteal reaction, and pathologic fracture.
Benign tumors are more common in young people, malignant bone tumors are more common in >40 y/o (chance of metastatic ca in > 40 is 500 times higher than primary bone sarcoma).
Included in differential diagnosis may be infection, stress fracture, myositis ossificans, metabolic bone disease, osteonecrosis, and synovial proliferative diseases.
Lab Tests
| Serum calcium (can be life-threatening) |
| Serum immunoglobulin (SPEP, UPEP) |
| Prostate-specific-antigen |
| ESR |
| Pregnancy test (for woman of child-bearing age) |
| CBC with diff |
| BMP |
| LFT’s, Ca, Phos, Alkaline phosphatase |
Imaging
| X-rays of affected bone |
| CT of chest, abdomen, and pelvis with contrast |
| Bone scan |
| MRI only if primary sarcoma considered |
***If primary diagnosis is not known, biopsy must be obtained to rule out primary bone lesion
Goals of treatment of metastatic bone disease include pain relief, preservation of function, and long lasting construct providing immediate weight bearing. Care is palliative and not curative. PMMA can help as an adjunct to help provide immediate structural stability combined with implants.
Healing rates: 37% for breast ca, 0% lung ca, 44% kidney ca, 67% for myelomas
Fixation should encompass the entire bone, when possible
Postoperative external beam radiation is necessary in most cases to prevent disease progression, and should include the entire operative field (usually the entire bone).
Fixation of specific lesions
When there is enough remaining bone with structural integrity, it may be used to anchor a nail or plate augmented with PMMA. When bone is mechanically incompetent, massive bone loss, or joint surface is destroyed, bone is removed and replaced with a prosthesis.
Humeral diaphysis – IM nail or combo of plate and PMMA (biomechanically superior to nail).
Periacetabular defects – lesions that do not breach the joint treated with screws and PMMA. Larger defects treated with antiprotrusio cage that bypasses lytic zone and rests on solid host bone, cup cemented in.
Femoral neck lesions – Arthroplasty.
Minimally invasive treatment options: radiation therapy (localized bone pain with no impending risk of fx); radiofrequency ablation; percutaneous cryoplasty; perc injection of PMMA with radiation after the procedure.