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.
Grade describes 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.