Treatment of malignant bone tumours with the Haifu System

Clinical applications of the Haifu System

The first patient to receive HIFU therapy in China had a primary osteosarcoma of the femur. He was treated at Second Hospital of Chongqing Medical University in December 1997, and was the first of many patients with malignant bone tumours to be treated using HIFU. Clinical results have shown that HIFU is a safe, effective and feasible method of treating malignant bone tumours. It has the great advantage that limb salvage may be possible in patients who would otherwise require an amputation. The risk of pathological fracture in the affected limb following treatment is increased, therefore extra care is required in the post-therapy period. HIFU may be used alone or in combination with chemotherapy with curative intent. This can be as primary therapy or after failure of conventional treatment. For palliation, HIFU may reduce pain associated with malignancy, and improve quality of life.

Kaplan-Meier survival curve of 96 patients with primary malignant bone tumour treated by HIFU ablation.

Comparison of Kaplan-Meier survival curves between patients in stage IIB (n = 72) and stage IIIB (n = 24)

The therapeutic effects

Fig.1. DSA images obtained in a 22-year-old patient who underwent a single HIFU treatment for an osteosarcoma of the distal femur. A) Pre-HIFU image showing the fine capillary network within the tumour (arrow); B) Image obtained 3 months post-HIFU showing disappearance of the capillary network, consistent with tumour ablation (arrow).

Fig.2. Contrast-enhanced MR images obtained in a 45-year-old patient who underwent HIFU ablation for tibia osteosarcoma: A) Before HIFU, tumor vascular perfusion was obvious; B) Two weeks after HIFU, the absence of contrast enhancement on 11-weighted image in the treated tumour (arrow).

Fig.3. CT images obtained in a 22-year-old patient who underwent HIFU treatment for distal femur osteosarcoma: A1-2) Image obtained before HIFU showed tumour in the soft tissue (arrow), and bone cortex was destroyed by neoplastic tissue (arrow); B1-2) Image obtained 5 years after HIFU showed disappearance of tumour in the soft tissue, and the destroyed cortex was completely repaired by the normal tissue (arrow).

Fig.4.Tc-99m methylene diphosphonate ECT image obtained in a 10-year-old patient who underwent HIFU ablation for the treatment of a 46cm long right femoral and tibial osteosarcoma. This patient had previously received chemotherapy without success. He is currently in complete remission 18 months after HIFU. A) Image obtained before HIFU showed focal area of increased uptake, which corresponded to a local abnormality (arrow); B) Image obtained 2 weeks after HIFU showed that the tracer uptake of treated tumour disappeared completely in the treated region (arrow).