High-intensity focused ultrasound (HIFU) is not indicated for treatment of primary bone sarcomas



Surgery is the method of choice for local treatment of osteosarcoma. Experimental approaches should not be considered “safe” unless they are proven to produce equivalent local control rates.

Li et al.'s report on high-intensity focused ultrasound (HIFU) concludes that the procedure is “safe and feasible” and “appears to be successful in the treatment of primary malignant bone tumors.”1 Their article, however, does not support such unwarranted claims. It is worth comment because it includes 13 patients with primary bone sarcomas, including 12 osteosarcomas. The authors do not provide the information, but presumably these were localized lesions.

Surgical remission status is the most important prognostic factor in osteosarcoma. So what was the justification for withholding surgery as potentially curative local treatment and opting for an experimental approach instead? With adequate surgery and chemotherapy, long-term, disease-free survival can be achieved in 60% to 70% of localized extremity and approximately 30% of axial or primary metastatic osteosarcomas. In contrast, the survival curve presented by Li et al. (Fig. 4) drops to <10% and seems to show only 1 survivor at 80 months.1 If anything, this is worse than what can be achieved with first-line treatment consisting of chemotherapy only, devoid of any form of local therapy.2

Any article on local therapy must include reliable information about the local efficacy of the chosen procedure. In bone sarcomas, imaging may give some hints about response, but it is notoriously unreliable in predicting complete tumor devitalization. The gold standard of local efficacy is freedom from local failure or progression, and local failure is uncommon after surgery of extremity osteosarcomas. If it does occur, it is most often followed by systemic progression and death. Any alternative to surgery must therefore achieve similarly high local control rates before it may be called “safe.” Here, Li et al. obviously fail to prove their case. The reader is left in the complete dark about the local control rate of HIFU in primary malignant bone tumors.

We are very concerned about the authors' decision to withhold curative treatment in favor of a purely experimental approach. Unfortunately, the accompanying editorial does not seem to take up the issue of this being unacceptable therapy for newly diagnosed patients with osteosarcoma and, in fact, indicates that HIFU may be a reasonable alternative for those choosing not to undergo surgery.3 At present, this is clearly not the case.