Sister diagnosed with osteosarcoma..is this a rare disease? is it treatable?

It is well known dis: Osteosarcoma is a cancer of the bone which requires a sarcoma specialist for best treatment. It is curable in a large proportion of patients provided they are treated by a team of medical oncologist and an orthopedic surgeon working as a team together. I would ask you to seek a second opinion from a known sarcoma center which are only found in major cancer centers.