The following are prognostic and predictive factors for childhood osteosarcoma.
Metastasis is when cancer spreads from where it started to another part of the body. Whether or not the cancer has already spread when it is first diagnosed is the most important prognostic factor for childhood osteosarcoma. Metastasis is linked with a poorer prognosis. Children with osteosarcoma that has only spread to a lung have a more favourable prognosis than those with metastasis in other parts of the body.
Tumours farther from the centre of the body have a better prognosis than tumours closer to the centre of the body. This may be because tumours farther from the center of the body are usually easier to remove surgically.
Tumours in the upper arms or upper legs have a better prognosis than tumours in the pelvis, chest or spine. Tumours in the pelvis, chest or spine tend to have the poorest prognosis because they are often detected late and are often larger and closer to other important organs making it more difficult to completely remove them.
Chemotherapy is sometimes given to reduce the swelling surrounding the tumour making surgery easier. This is called neoadjuvant chemotherapy. Children with osteosarcoma that responds well to neoadjuvant chemotherapy (more than 95% of the tumour cells are killed) have a better prognosis than children with osteosarcoma that does not respond to neoadjuvant chemotherapy.