Osteosarcoma

General

  1. Surgery is the mainstay of treatment with chemotherapy effective for osteogenic sarcoma.
  2. 16,300 new cases a year with 13,800 of the cases are multiple myeloma (50% of all bone tumors is derived from plasma cells).
  3. Osteogenic sarcoma is the most common. The others include chondrosarma, giant cell tumor of the bone, chordoma, MFH of the bone and Ewing\’s sarcoma
  4. Present with pain, limb dysfunction, pathological fracture, and DM to the lung.
  5. 60% occur between 10-20 years in distal femur and proximal tibia for OS.
  6. Bone sarcomas are the most common second malignancy after radiation; a 2.7 fold increased risk, especially after 50Gy. This is true for retinoblastoma, a 200 to 500 x risk.

Work-up

  1. H/P
  2. Radiological features: plain films, bone scan, CT scan of extremity, MRI of the extremity, CT of the chest.
  3. Consider PET scan
  4. Labs: CBC, CHEM20
  5. Biopsy (avoid incision over area not to be irradiated or re-excised).

Pathology

Subclassification of Osteosarcoma by histology and orgin

Origin and Histology Risk of Death
Primary Tumors
Conventional - Osteoblastic 14.4
Conventional - Chondroblastic 9.6
Conventional - Fibroblastic 10.7
Telangiectatic 14.5
Secondary Tumors
Associated with Paget's 64.2
Juxtacortical tumor
Parosteal 1.0
Periosteal 1.0 (lowest risk of metastasis)

Staging

AJCC Staging for Malignant Bone Tumors

T1 <= 8cm
T2 > 8cm
T3 Multiple/discontinuous tumors
N1 Regional lymph node involvement
G1 Well-differentiated
G2 Moderately differentiated
G3 Poorly differentiated
G4 Undifferentiated
  • Ewing's sarcoma is classified as G4
Stage IA G1 or 2 T1 N0 M0
Stage IB G1 or 2 T2 N0 M0
Stage IIA G 3 or 4 T1 N0 M0
Stage IIB G 3 or 4 T2 N0 M0
Stage III Any G T3 N0 M0
Stage IVA Any G Any T N0 M (lung only)
Stage IVB Any G Any T Any N Any M

Radiological Features

  1. **OS **(cloud like density representing osteoid) commonly arise in the metaphyseal region. "Sunburst" pattern. Destruction of the cortical bone results in the Codman\’s triangle on plain films. MRI will show tumor extension and skip lesions.

Treatment Recommendations

  1. In general, limb sparing strategies preferred, which may involve combination of neoadjuvant chemo, RT and surgery
  2. In children, RT has added implications on growth of limb and future function.
  • Osteosarcoma: Preop chemo  surgery  adjuvant chemo x 4-6 mo
  • Consider clinical trial
  • Inoperable or close/+margin  RT to 60-75 Gy with shrinking fields
  • Pelvic tumors  Consider intra-arterial chemo (cisplatin/doxorubicin) + 60-70 Gy
  • M1a: Surgical resection of lung metastases improves survival
  1. **Surgery alone: **Amputation was classic procedure but if limb-sparing surgery can be done then preferred, especially for expendable bones such as fibula, ulna, and patella. Grafts and prosthesis are often needed. LC good but 80% have DM.
  • Surgery + Chemotherapy: MSK proposed neoadjvant methotrexate, vincristine, Adriamycin, and cyclophosphamide (MVAC) and then amputation. The** T-10 protocol used Methotrexate, Vincristine, Adriamycin, Bleomycin and Cisplatin with 76% RFS for CMT. The tumor response to chemotherapy is a prognostic factor and determines drugs used. **Multi-institutional Osteosarcoma Study__ __did a randomized study using the same regimen and showed the RFS was 12% for the control group and 63% for the CMT.
  • Randomized trials have established that neoadjuvant and adjuvant chemo help to prevent relapse or recurrence in pts with localized resectable primary tumors (Link, NEJM, 1986; JCO, 1987)
  • Cooperative German/Austrian Osteosarcoma Study Group (JCO 2003). Subset analysis of 67 pts with non-metastatic, high-grade pelvic osteoscarcomas. RT improved survival for pts with intralesional excision and unresectable tumors.
  • DeLaney (IJROBP 2005). Review of 41 pts with osteosarcoma that were either unresectable or had close + margins and were treated with RT. No definitive dose-response, although doses >55 Gy had higher LC (p= 0.11). RT more effective for pts with microscopic or minimal residual dz.
  1. Radiotherapy: no primary role in the treatment of OS except for unresectable lesions near the spinal cord/vital organs or involving facial or pelvic bones. LC is poor and is used with chemotherapy. PMH showed that RT alone was not effective for LC, meaningful palliation, or useful limb. Caceres showed that pre-op RT/surgery showed some improved LC but no change in survival. Whole lung treatment has been advocated by some (15-18Gy)

Radiation Techniques

  • Spare 1.5-2.0 cm strip of skin in extremity if possible to prevent lymphedema.
  • Include entire surgical bed + scar + 2 cm margin if possible
  • CT/MRI data for tx planning

Dose Limitations

  • > 20 Gy can prematurely close epiphysis
  • > 40 Gy will ablate bone marrow
  • > 50 Gy to bone cortex significantly increases risk of fx

Complications

  • Abnormal bone and soft tissue growth and development, permanent weakening of bone, scoliosis, decreased range of motion due to fibrosis or joint involvement, lymphedema, telangiectasia, osteoradionecrosis
  • Increased risk of 2nd cancers (leukemia, sarcomas)
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