Imaging of Primary and Recurrent Tumours

Background: Cartilaginous tumours may present diagnostic and prognostic dilemmas. Heterogeneity of appearance and histology sometimes confound our ability to make accurate diagnoses of the state of malignancy and grade. Conventional methods that combine history, plain radiographs, and histology may result in both under and over treatment. A method, which allows preoperative assessment of malignancy and grade would be valuable in developing a rationale plan for treatment. We examined the correlation between specific nuclear tracer avidity and malignancy in cartilage tumours. Methods: Thallium-201 (Tl-201) and pentavalent dimercaptosuccinic acid (DMSAV) are two isotopes which when used as nuclear tracers, may provide enhanced information regarding the biologic activity of cartilage tumours. Our study examined 92 consecutive cartilage tumours (50 benign, 42 malignant), which were treated at our institution between 1996 and 2000 and analysed the correlation between Tl-201 and DMSAV scanning and malignancy and grade. Results: We noted that patients with negative DMSAV scans (25) had benign tumours. 15 of 17 patients with positive TL-201 scans had malignant tumours. Patients with both positive DMSAV and TL-201 scans (11/13) had intermediate or high grade tumours. One of two patients with positive DMSAV and Tl-201 scans but with an apparently benign tumour demonstrated chromosomal changes consistent with chondrosarcoma. Four of thirteen patients with positive DMSAV and TL-201 scans developed metastases. Conclusion: From our results we were able to develop an algorithm for the management of patients with cartilaginous tumours that aims to avoid over treatment of low grade tumours, or under treatment of high grade tumours. We conclude that functional nuclear scanning with DMSAV and Tl-201 is a valuable technique in the management of cartilaginous tumours.