MR-Guided Focused Ultrasound Alleviates Painful Bone Metastases

Non-invasive thermal tissue ablation technique allows relief from pain due to bone metastases for patients who are refractory to medication and do not respond to radiotherapy

medwireNews: Magnetic resonance-guided focused ultrasound surgery (MRgFUS) is an effective treatment option for alleviating pain due to bone metastases in patients who do not respond to or are unsuitable for radiotherapy, or who decline it, phase III trial results indicate.

Researchers Mark Hurwitz, from Thomas Jefferson University in Philadelphia, Pennsylvania, USA, and colleagues found that response to the treatment was rapid, occurring within days for two-thirds of patients, and nearly half of patients were able to reduce or completely stop their pain medication following treatment.

The non-invasive thermal tissue ablation technique enables physicians to perform precise localised tumour tissue ablation with real-time temperature monitoring, comment the trial researchers.

They randomly assigned 112 patients to undergo MRgFUS and 35 to receive a placebo procedure where the sonication was turned off. Prior to treatment, pain in the treated lesion scored at least 4 on the Numerical Rating Scale (NRS) despite optimisation of pain medication.

At 3 months, 64.3% of patients receiving MRgFUS responded to treatment, defined as at least a 2-point improvement in worst NRS score and an increase in morphine equivalent daily dose intake of no more than 25% from baseline. This compared with just 20.0% of patients receiving the placebo procedure.

The researchers note in the Journal of the National Cancer Institute that MRgFUS was also associated with a “clinically significant, rapid and durable” reduction in scores on the Brief Pain Inventory, indicating less interference of pain with quality of life, whereas there was no change with placebo.

The most common adverse effect of the procedure was pain during sonication, affecting 32.1% of patients, and was cited as the reason for not completing the full complement of planned sonications by three of five patients. The reason given by the other two patients was the length of time the treatment took, at an average 83 minutes of sonication and a total 176 minutes inside the scanner.

Of 63 adverse events reported overall, 60.3% were transient and resolved on the day of treatment. A further 14.3% resolved within a week. The most clinically significant of those lasting more than a week were a third-degree burn in one patient and fractures in two patients, one of which was outside the treated area.

The researchers comment that their “results compare well with the complication rate of [radiotherapy].”

They conclude that “MRgFUS should be considered a viable treatment option for painful bone metastases”, and recommend future studies “to assess the role of MRgFUS in patients with bone metastases as first-line therapy.”

Reference

Hurwitz MD, Ghanouni P, Kanaev SV, et al. Magnetic Resonance-Guided Focused Ultrasound for Patients With Painful Bone Metastases: Phase III Trial Results. J Natl Cancer Inst 2014; Advance online publication April 23. doi: 10.1093/jnci/dju082

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