A patient’s prognosis varies greatly based on the type of cancer and how far it has spread. Staging enables a physician to determine a patient’s prognosis and choose the most appropriate treatment methods. Results from physical examination, biopsies and imaging tests are used to determine the stage.

These stages are created by a process called stage grouping. In this process information about a number of factors are combined to assign a stage.

The TNM system of the American Joint Committee on Cancer (AJCC) is the most common system used to stage cancer. In this system:

• T represents tumor. The location of the tumor can either be inside the bone or extend outside the bone.
  
  
• N represents absence or presence of spread to lymph nodes. Part of the immune system, lymph nodes are small, bean-shaped organs located in groups in various areas of the body, including the neck, armpit, chest and groin. Their functions include fighting infections and other foreign invaders, such as cancer.
  
  
• M represents absence or presence of metastasis, or spread of the cancer to distant organs.
  
  

  

Typically the stages are described by Roman numerals I to IV. However, some types of childhood bone cancers, such as Ewing’s tumor and osteosarcoma, are not staged this way. Instead, these cancers are often grouped into two stages – localized and metastatic.

According to the American Cancer Society (ACS), the five-year survival rate for patients in the different stages of bone cancer includes:

For patients with the most common form of bone cancer (osteosarcoma), survival rates may be based simply on two categories – cancer that is confined to the bone and cancer that has spread. For those patients whose cancer has not spread, there is a 60 to 70 percent 5-year survival rate. If it has spread only to the lungs, it is estimated to be 40 percent and only 10 percent if the cancer has spread elsewhere in the body.