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Understanding Your Grade and Stage of Primary Bone Cancer

Primary bone cancer acts differently in each person. Your doctor uses staging studies, such as a biopsy and imaging tests, to determine how fast your cancer is growing and how far it has spread. With the results of these studies, your doctor will assign your cancer a grade and a stage.

Gradedescribes how the cancer cells from the biopsy look under the microscope. The higher the grade, the more abnormal the cells and the�faster they are likely to spread. Primary bone cancer has�four grades. Cancer cells in low-grade�(grade 1 or 2) tumors�appear similar to normal bone cells. They are usually slow-growing and less likely to spread. The cells in high-grade (grade 3 or 4) tumors look very abnormal. They are likely to grow more quickly and spread.

Stage�is assigned based on the grade, the size of the cancerous tumor, and where and how far it has spread. Most bone cancers are�classified into one of four stages:

  • Stage I. The cancer is confined to the bone and is low-grade.

  • Stage II. The cancer is confined to the bone but is high-grade.

  • Stage III. The cancer is in more than one place in the same bone and is high grade.

  • Stage IV. The cancer has spread outside the bone. It can be low- or high-grade.

The first place cancer is found in the body is called the primary site or primary tumor. Cancer that has spread is called metastatic.