Bone cancer is diagnosed in less than 1 percent of patients, although it can appear in any type of bone tissue—hard (osteoid), tough and flexible (cartilaginous), or thin/threadlike.
It can also develop in the marrow, or the soft, spongy center of the bone.
There are 3 common types of bone cancer:
- Osteosarcoma: Tumors form in the bone’s osteoid tissue, commonly found in the knee or upper arm.
- Chondrosarcoma: Develops in the body’s cartilaginous tissue, or cartilage—the connective tissue found at the ends of bones and along the joints. This type of cancer usually develops in the pelvis, upper leg, or shoulder.
- Ewing Sarcoma Family of Tumors (ESFT’s): This group of tumors usually appears in bone tissue, but can also develop in the soft tissue of the body, including muscle, fat, blood vessels, or other tissue. ESFT’s are commonly found along the spine, pelvis, and limbs. Soft tissue can also develop a type of cancer called soft tissue sarcoma; however, this is not considered to be a form of bone cancer.
Bone Cancer’s Stages
A stagehelps a doctor to determine if, and how much, the cancer has spread. Unlike most other forms of cancer, whose advancement is identified by a number, bone cancer’s stages are designated by letters.
Each level of the stage is then followed by a Roman numeral (I-IV) as are other forms of cancer:
T: for “tumor”
N: for “spreads to lymph nodes”
M: for “metastasis to distant organs”
G: for “grade of the tumor”. G1-G2 is considered low grade; G3-G4 is considered high grade.
When the letter/number stages have been determined, the information is gathered and an overall grade is assigned to the patient’s condition:
- Stage I: All tumors are considered low-grade and therefore have not spread outside of the bone
- Stage II: At Stage II, tumors have not spread outside of the bone but are considered high grade
- Stage III: Stage III tumors have not spread outside of the bone, but several tumors developed on the same bone. These tumors are considered high grade.
- Stage IV: A Stage IV tumor has spread outside of the bone where they began. These tumors can be either low or high grade.