From the Guidelines
The Enneking classification system for bone tumors is based on histological grade and extent in relation to anatomical compartments, with stage III tumors having metastases, as described in the most recent study 1. The Enneking system uses the following stages:
- Stage I: low-grade tumors (G1) that are either intracompartmental (IA) or extracompartmental (IB)
- Stage II: high-grade tumors (G2) that are either intracompartmental (IIA) or extracompartmental (IIB)
- Stage III: any grade tumor with metastasis (G1-2, T1-2, M1) This classification is valuable because it guides surgical decision-making, with stage I malignant tumors typically requiring wide excision, stage II requiring wide excision with possible adjuvant therapy, and stage III requiring wide excision with definitive adjuvant therapy, as supported by the study 1. The system's strength lies in its correlation with prognosis and its ability to standardize treatment approaches across different institutions, making it a crucial tool in the management of bone tumors, as noted in the study 1. Some key points to consider when using the Enneking classification system include:
- The importance of accurate staging in determining the appropriate treatment approach
- The need for a multidisciplinary approach to treatment, including surgery, chemotherapy, and radiation therapy
- The potential for variation in treatment outcomes based on factors such as tumor location, size, and grade, as discussed in the study 1.
From the Research
Enneking Classification for Bone Tumors
The Enneking classification is a system used to stage bone tumors, taking into account the grade of the tumor, its location in relation to anatomic compartments, and the presence or absence of distant metastasis. This system is crucial for determining the appropriate treatment and prognosis for patients with bone tumors.
Key Components of the Enneking Classification
- Grade (G): The grade of the tumor is based on its histological characteristics, with G1 being low-grade and G2 being high-grade 2.
- Location (T): The location of the tumor is classified as T1 (intracompartmental) or T2 (extracompartmental) 2.
- Metastasis (M): The presence or absence of distant metastasis is denoted as M0 (no metastasis) or M1 (metastasis) 2.
Staging of Bone Tumors Using the Enneking System
The Enneking system stages bone tumors into four categories:
- Stage IA: Low-grade tumor, intracompartmental, no metastasis
- Stage IB: Low-grade tumor, extracompartmental, no metastasis
- Stage IIA: High-grade tumor, intracompartmental, no metastasis
- Stage IIB: High-grade tumor, extracompartmental, no metastasis
- Stage III: Any grade tumor with metastasis 2, 3.
Treatment Based on the Enneking Classification
The Enneking classification guides the choice of surgical procedure, with:
- Grade I procedures (intralesional curettage or excision) for benign tumors
- Grade II procedures (marginal excision) for Stage IA tumors
- Grade III procedures (wide intracompartmental resections) for Stage IIA and IIB lesions
- Grade IV procedures (radical resection) for Stage IIB lesions or tumors with metastasis 2, 4.
Efficacy of the Enneking Staging System
Studies have shown that the Enneking staging system is effective in determining the prognosis and guiding treatment for benign bone tumors and tumor-like bone lesions, with a high agreement rate between the initial staging and treatment outcomes 4, 5. However, the system has its limitations, including inflexibility and the need for updates to reflect changes in radiological modalities 3, 6.