Which parameter is incorporated in the American Joint Committee on Cancer (AJCC) staging system for primary malignant bone tumours but is absent from the Enneking (MSTS) surgical staging system?
- A Maximum tumour dimension, with 8 cm as the cutoff ✓
- B Presence of distant metastasis
- C Histological grade of the tumour
- D Compartmental status of the lesion
Correct answer: A. Maximum tumour dimension, with 8 cm as the cutoff
Explanation
The AJCC system for bone sarcomas incorporates tumour size (T1 is 8 cm or less, T2 more than 8 cm, T3 a skip lesion), histological grade, nodal status and metastasis. The Enneking system instead uses grade, compartmental extent (intracompartmental versus extracompartmental) and metastasis, and does not measure absolute size. Both systems include grade and metastasis, so those options fail to discriminate between the two classifications.
Reference: Campbell's Operative Orthopaedics, 14th ed.
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