New TNM classification (AJCC eighth edition) of bone and soft tissue sarcomas: JCOG Bone and Soft Tissue Tumor Study Group

The Cancer Staging Manual of the American Joint Committee on Cancer (AJCC) has recently been revised and updated to its eighth edition. This review focuses on the new staging system of bone and soft tissue sarcomas and outlines the revision points and caveats in the latest edition. The major changes in the eighth edition of the AJCC staging for bone and soft tissue sarcomas are the following four points. (i) Tumors are described separately according to the primary sites. For bone sarcoma, three tumor locations are described: (a) appendicular skeleton, trunk, skull and facial bones; (b) spine and (c) pelvis. Meanwhile, four tumor locations are described for soft tissue sarcoma: (1) trunk and extremity; (2) retroperitoneum; (3) head and neck and (4) visceral sites. (ii) Histologic grading system in bone sarcoma is changed to three-grade classifications. (iii) For soft tissue sarcoma, AnyTN1M0 tumor in the trunk and extremity is classified as stage IV, whereas for the retroperitoneal tumor, anyTN1M0 remains as stage IIIB. (iv) For soft tissue sarcomas in the trunk, extremity and retroperitoneum, tumor size was classified into four categories: (a) ≤5 cm; (b) >5 cm and ≤10 cm; (c) >10 cm and ≤15 cm and (d) >15 cm. In addition, the notation about the depth of the tumor (superficial or deep from the superficial fascia) has been eliminated.