Bone Cancer Prognosis
The prognosis for patients who have primary bone cancer varies, depending on the type and stage of the cancer. The American Joint Commission on Cancer (AJCC) system is used to stage bone cancer.
Staging of Bone Cancer
Using the AJCC Staging System, T stands for the size of the tumor, N stands for lymph node involvement, M stands for spread (metastasis) to distant organs, and G stands for the tumor grade. The grade of the tumor (i.e., how abnormal the cells appear under microscopic evaluation) can be used to help determine how quickly the tumor is likely to grow and spread. This information is then combined and a stage (e.g., 1–4 or I–IV) is assigned to the cancer.
- T0: No evidence of the tumor
- T1: Tumor is 8 cm (3 inches) or less
- T2: Tumor is larger than 8 cm
- T3: Tumor cells detected at another site(s) on the same bone
- N0: No spread to nearby (regional) lymph nodes
- N1: Cancer detected in nearby lymph nodes
- M0: No distant metastasis
- M1: Distant metastasis (cancer has spread to other tissues or organs)
- M1a: Cancer has spread only to the lung
- M1b: Cancer has spread to other sites
- G1–G2: Low grade
- G3–G4: High grade
Bone Cancer Grades
TNM Staging of Bone Cancer
Stage IA: T1, N0, M0, G1-G2: Tumor is confined to the bone, less than 8 cm in size, and is low grade.
Stage IB: T2, N0, M0, G1-G2: Tumor is confined to the bone, larger than 8 cm, and is low grade.
Stage IIA: T1, N0, M0, G3-G4: Tumor is confined to the bone, less than 8 cm, and is high grade.
Stage IIB: T2, N0, M0, G3-G4: Tumor is confined to the bone, larger than 8 cm, and is high grade.
Stage III: T3, N0, M0, Any G: Tumor is confined to the bone but tumor cells are detected at other sites on the bone.
Stage IVA: Any T, N0, M1a, Any G: Tumor has spread to the lung.
Stage IVB: Any T, N1, Any M, Any G: Tumor has spread to lymph nodes and distant sites, or Any T, Any N, M1b, Any G: Tumor has spread to distant sites other than the lung.
Stage 1 (I) tumors present the best prognosis and Stage 4 (IV) tumors present the worst prognosis.