Is Skeletal Imaging Essential in the Staging Workup for Conventional Chondrosarcoma?

Area of Science:

• Orthopaedic oncology
• Medical imaging
• Skeletal oncology

Background:

• Current staging for chondrosarcoma, a type of bone sarcoma, follows general guidelines for bone sarcomas.
• There are no specific staging recommendations for chondrosarcoma, despite skeletal metastases being rare.

Purpose of the Study:

• To determine the proportion of chondrosarcoma patients presenting with isolated skeletal metastases.
• To assess the proportion of chondrosarcoma patients with skeletal metastases, with or without concurrent pulmonary metastases.

Main Methods:

• Retrospective analysis of 427 patients with histology-proven chondrosarcomas (2006-2017).
• Patients were staged using thoracic CT and bone scan or FDG PET/CT.
• Metastases were reviewed by experienced radiologists and nuclear medicine experts.

Main Results:

• Only 3 patients (0.7%) had isolated skeletal metastases; none had Grade 1 or Grade 3.
• No patients with Grade 1 chondrosarcoma had detectable bone metastases.
• Combined lung and bone metastases were observed in 2 patients with Grade 2 chondrosarcoma.

Conclusions:

• The incidence of skeletal metastases in conventional chondrosarcoma is very low.
• Skeletal imaging in the staging of chondrosarcoma may be overutilized.
• Consider omitting skeletal imaging from initial staging, reserving it for patients with pulmonary metastases.