MUSCULOSKELETAL TUMOR SOCIETY CLASSIFICATION
In 1980, the Musculoskeletal Tumor Society (MSTS) adopted a surgical staging system for bone sarcomas. The system is based on the fact that mesenchymal sarcomas of bone behave similarly, regardless of histiogenic type. The surgical staging system, as described by Enneking and colleagues, is based on the GTM classification: grade (G), location (T), and lymph node involvement and metastases (M).
G represents the histologic grade of a lesion and other clinical data. Grade is further divided into two categories: G1 is low grade, and G2 is high grade.
T represents the site of the lesion, which may be intracompartmental (T1) or extracompartmental (T2). Compartment is defined as “an anatomic structure or space bounded by natural barriers or tumor extension.” The significance of T1 lesions is easier to define clinically, surgically, and radiographically than that of T2 lesions, and the chance is better for adequate removal of the former without amputation. In general, low-grade bone sarcomas are intracompartmental (T1), whereas high-grade ones are extracompartmental (T2).
Lymphatic spread is a sign of widespread dissemination. Regional lymphatic involvement is equated with distal metastases (M1). Absence of any metastasis is designated as M0.
The surgical staging system developed by Enneking and colleagues for surgical planning and assessment of bone sarcomas is summarized thus:
Stage IA (G1,T1,M0): low-grade intracompartmental lesion, without metastasis
Stage IB (G1,T2,M0): low-grade extracompartmental lesion, without metastasis
Stage IIA (G2,T1,M0): high-grade intracompartmental lesion, without metastasis
Stage IIB (G2,T2,M0): high-grade extracompartmental lesion, without metastasis
Stage IIIA (G1 or G2,T1,M1): intracompartmental lesion, any grade, with metastasis
Stage IIIB (G1 or G2,T2,M1): extracompartmental lesion, any grade, with metastasis
AMERICAN JOINT COMMITTEE ON CANCER BONE TUMOR CLASSIFICATION
In 1983, the American Joint Committee on Cancer Bone Tumor Classification (AJCC) recommended a staging system for the malignant tumors of bone. This system has undergone minimal changes and remains unchanged in the fifth edition of the AJCC Cancer Staging Manual. This system is based on two indications: TNM designation [extent of the tumor (T), nodal status (N), and distant metastases (M)] and grade (G). This system is similar to the MSTS classification; however, the AJCC uses four stages instead of three. The four stages are designated I to IV and may be further modified with A or B. Stages I and II are defined by the histologic grade (grade I and II) and modified by tumor extent (i.e., cortical involvement; designated E1 to E6) . T(I) indicates that the tumor is confined within the cortex (similar to the MSTS classification A), and T(II) indicates that the tumor extends beyond the cortex (similar to the MSTS classification B). In the AJCC, stage III has remained undefined and stage IV is defined as the presence of metastases. Stage IV tumors are modified by A, which is equivalent to III M1 in the MSTS system (i.e., indicates a nodal metastasis), and B, which is equivalent to III M1 in the MSTS system (i.e., indicates distant metastases).
In 1980, the Musculoskeletal Tumor Society (MSTS) adopted a surgical staging system for bone sarcomas. The system is based on the fact that mesenchymal sarcomas of bone behave similarly, regardless of histiogenic type. The surgical staging system, as described by Enneking and colleagues, is based on the GTM classification: grade (G), location (T), and lymph node involvement and metastases (M).
G represents the histologic grade of a lesion and other clinical data. Grade is further divided into two categories: G1 is low grade, and G2 is high grade.
T represents the site of the lesion, which may be intracompartmental (T1) or extracompartmental (T2). Compartment is defined as “an anatomic structure or space bounded by natural barriers or tumor extension.” The significance of T1 lesions is easier to define clinically, surgically, and radiographically than that of T2 lesions, and the chance is better for adequate removal of the former without amputation. In general, low-grade bone sarcomas are intracompartmental (T1), whereas high-grade ones are extracompartmental (T2).
Lymphatic spread is a sign of widespread dissemination. Regional lymphatic involvement is equated with distal metastases (M1). Absence of any metastasis is designated as M0.
The surgical staging system developed by Enneking and colleagues for surgical planning and assessment of bone sarcomas is summarized thus:
Stage IA (G1,T1,M0): low-grade intracompartmental lesion, without metastasis
Stage IB (G1,T2,M0): low-grade extracompartmental lesion, without metastasis
Stage IIA (G2,T1,M0): high-grade intracompartmental lesion, without metastasis
Stage IIB (G2,T2,M0): high-grade extracompartmental lesion, without metastasis
Stage IIIA (G1 or G2,T1,M1): intracompartmental lesion, any grade, with metastasis
Stage IIIB (G1 or G2,T2,M1): extracompartmental lesion, any grade, with metastasis
AMERICAN JOINT COMMITTEE ON CANCER BONE TUMOR CLASSIFICATION
In 1983, the American Joint Committee on Cancer Bone Tumor Classification (AJCC) recommended a staging system for the malignant tumors of bone. This system has undergone minimal changes and remains unchanged in the fifth edition of the AJCC Cancer Staging Manual. This system is based on two indications: TNM designation [extent of the tumor (T), nodal status (N), and distant metastases (M)] and grade (G). This system is similar to the MSTS classification; however, the AJCC uses four stages instead of three. The four stages are designated I to IV and may be further modified with A or B. Stages I and II are defined by the histologic grade (grade I and II) and modified by tumor extent (i.e., cortical involvement; designated E1 to E6) . T(I) indicates that the tumor is confined within the cortex (similar to the MSTS classification A), and T(II) indicates that the tumor extends beyond the cortex (similar to the MSTS classification B). In the AJCC, stage III has remained undefined and stage IV is defined as the presence of metastases. Stage IV tumors are modified by A, which is equivalent to III M1 in the MSTS system (i.e., indicates a nodal metastasis), and B, which is equivalent to III M1 in the MSTS system (i.e., indicates distant metastases).
Tidak ada komentar:
Posting Komentar