A surgical staging system for malignant lesions is most logically accomplished by assessment of the surgical grade (G), the local extent (T), and the presence or absence of regional or distant metastases (M) (Table 5.2).

Any neoplasm can be divided into two grades, low (G₁) and high (G₂). In general, low-grade lesions correspond to Broders I and II and have less than a 25 % chance of metastasis. High-grade lesions (Broders III and IV) have a greater risk for local recurrence and greater than 25 % chance of metastasis.

The anatomic extent (T) is subdivided by whether the lesion is intracompartmental (A) or extracompartmental (B). Anatomic compartments have natural barriers to block or delay tumor extension: in bone, the barriers are cortical bone and articular cartilage; in joint, articular cartilage and joint capsule; and in soft tissue, the major fascial septa and the tendinous origins and insertions of muscles.

The presence or absence of metastases (M) is the third major factor related to both prognosis and surgical planning.

Stage I is composed of low-grade lesions (G₁); stage II, high-grade lesions (G₂); and stage III lesions, those with either regional or distant metastases (G₁ or G₂, M₁). Stage I (G₁, M₀) and II (G₂, M₀) are further subdivided by the intracompartmental (T1) and extracompartmental (T2) settings.