Introduction Prognosis of bone cancer depends on the following variables overall stage of disease (incorporates all of the below) presence of metastasis skip (discontinous) lesions within the same bone histologic grade tumor size The are two staging systems that are commonly used: MSTS or Enneking System AJCC Staging System MSTS (Enneking) Staging System Introduction most popular and useful for orthopaedic surgeons two systems - one for malignant lesions and one for benign lesions malignant lesions are defined using Roman numerals (e.g. I, II, III) login to view 2 more bullets benign lesions are defined using Arabic numbers (1,2,3) login to view 9 more bullets MSTS Staging for Malignant tumors Stage Grade Site Metastasis IA Low Grade T1 - intracompartmental M0 (none) IB Low Grade T2 - extracompartmental M0 (none) IIA High Grade T1 - intracompartmenta M0 (none) IIB High Grade T2 - extracompartmental M0 (none) III Metastatic T1 or T2 - intra or extra-compartmental M1 (regional or distant) Tumor Compartments intracompartmental bone tumors are confined within the cortex of the bone extracompartmental bone tumors extend beyond the bone cortex Tumor Grade histologically, tumors are graded based on the percentage of cellular atypia low grade tumors login to view 2 more bullets high grade tumors login to view 2 more bullets AJCC Staging System AJCC Staging System Stage Grade Size Depth Node Metastasis 5 yr. survival IA Low Grade < 8cm Any None None 98% IB Low Grade > 8cm Any None None IIA High Grade < 8cm Any None None 82% IIB High Grade > 8cm Superficial None None 82% III Any Discontinuous (skip) lesion Deep None None 52% IVA Any Any Any None Lung IVB Any Any Any Present Other than lung 30% Prognosis for soft tissue tumors depends on grade low grade: G1 and G2 high grade: G3 and G4 size T1: < 8 cm T2 > 8 cm nodes N0: no regional nodes N1: regional nodes metastasis presence of distant metastasis automatically elevates patient to stage IV disease