Staging is essential to giving the patient accurate prognostic information, planning and monitoring treatment and conducting research to compare the outcomes of various interventions on different groups of patients.
Staging can be divided into local and systemic staging and investigations arranged accordingly.
The most widely used system is the Surgical Staging System proposed and validated by Enneking in 1980, which is used for all sarcomas.
There are 2 concepts that are important:
- The grade of the lesion:
- This is determined by histological analysis and predicts the risk of developing metastases (>15% risk of metastatic disease with a high grade OS)
- Most osteosarcomas are high grade
- Whether the lesion is contained or not within an anatomical compartment:
- This is a guide to the ease of resection of the lesion
- Some lesions arise outside contained compartments and are much more difficult to resect with limb salvage
- Most osteosarcomas are intracompartmental
Grade is denoted first with Roman numerals, I for low grade and II for high grade. III is used if metastases are already present at diagnosis.
Compartmental Status is denoted second as:
- A for intracompartmental
- B for extracompartmental
There is no need to denote compartment status if metastatic disease is present.
Surgical Staging System |
|
IA |
Low Grade, Intracompartmental |
IB |
Low Grade, Extracompartmental |
IIA |
High Grade, Intracompartmental |
IIB |
High Grade, Extracompartmental |
III |
Metastases |
A typical osteosarcoma is Stage IIA – a high grade, intracompartmental lesion.
Link: Osteogenic sarcoma staging at the NCI
