The degree of tumor necrosis following preoperative chemotherapy is a prognostic feature in patients with osteosarcoma.
Procedure:
• Chemotherapy is administered prior to resection of the bony tumor.
• After surgery the gross specimen is thinly cross sectioned and carefully diagrammed.
• A cross-section of the tumor is divided into cassettes, decalcified and then processed for histologic sections.
• The percent of viable and necrotic tissue in each section is determined.
• All of the findings are combined to give a total amount of viable and necrotic tissue for the cross-section.
Percent Necrotic Tumor |
Percent Viable Tumor |
Grade |
0% |
100% (no response to chemotherapy) |
I |
< 50% |
> 50% |
IIA |
50 - 95% |
5 - 50% |
IIB |
> 95% |
< 5% |
III |
100% |
0%(no viable tumor) |
IV |
from: Children's Cancer Group and Pediatric Oncology Group (Coffin, 1999)
Interpretation:
• A good response to chemotherapy is considered >= 90% necrosis.
• Patients with >= 90% tumor necrosis have a 91% disease free survival.
• Patients with < 90% tumor necrosis have a 14% disease free survival.
Limitations:
• Histologic interpretation may be subjective.
• Highly atypical cells that are found scattered in reactive stroma are counted as viable tumor by convention, but their significance has not yet been completely determined.
• Improper processing such as over-decalcification may introduce technical artifacts.
Specialty: Hematology Oncology, Surgery, general, Surgery, orthopedic
ICD-10: ,