Author: Patrick O'Donnell Topic updated on 03/12/13 10:14am 1

Stage Grade Site (1) MetastasisIA Low Grade T1 - intracompartmental M0 (none)IB Low Grade T2 - extracompartmental M0 (none)IIA High Grade T1 - intracompartmental M0 (none)IIB High Grade T2 - extracompartmental M0 (none)III Metastatic T1 - intracompartmental M1 (regional or distant)III Metastatic T2 - extracompartmental M1 (regional or distant)

Stage Grade Size Depth Node Metastasis 5 yr. survivalIA Low Grade < 8cm any none none 98%

IB Low Grade > 8cm 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%

Bone Tumor Staging Systems

Introduction

Prognosis of bone cancer depends on the following variables1. overall stage of disease (incorperates all of the below)2. presence of metastasis3. skip (discontinous) lesions within the same bone4. histologic grade5. 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 surgeonstwo systems - one for malignant lesions and one for benign lesions

malignant lesions are defined using Roman numerals (e.g. I, II, III)see table belowe.g. osteosarcoma most commonly presents as stage IIB

benign lesions are defined using Arabic numbers (1,2,3)1 = latent lesion

e.g. non-ossifying fibromaenchondroma

2 = active lesione.g. ABC, UBCchondromyxoid fibromachondroblastoma

3 = aggressive lesione.g. giant cell tumor of bone

Tumor Compartmentsintracompartmental

bone tumors are confined within the cortex of the boneextracompartmental

bone tumors extend beyond the bone cortexTumor Grade

histologically, tumors are graded based on the percentage of cellular atypialow grade tumors

low metastatic potentiale.g. parosteal osteosarcoma

high grade tumorsgreater metastastatic potentiale.g. intramedullary osteosarcoma, Ewing's sarcoma, dedifferentiatedchondrosarcoma

AJCC Staging System

III any discontinuous (skip) lesion deep none none 52%

IVA any any none lung IVB any any any present other thanlung 30%

Prognosis for soft tissue tumors depends ongrade

low grade: G1 and G2high grade: G3 and G4

sizeT1: < 8 cmT2 > 8 cm

nodesN0: no regional nodesN1: regional nodes

metastasispresence of distant metastasis automatically elevates patient to stage IV disease

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Qbank (1 Questions)

Question: 1 of 1Question: 1 of 1

TAG

(OBQ05.7) A 13-year-old girl presents with an isolated distal femur osteosarcoma that extends into the soft tissue. Work-up isnegative for metastasis, but biopsy reveals a high grade lesion. What is the stage of this tumor by the Musculoskeletal TumorSociety system? Review Topic

1. I A 2. II A 3. I B 4. II B 5. III

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Oral Boards: Bone Tumor Staging SystemsGeneral - Oral Boards Review

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