Non-surgical pain relief treatment for bone tumours

New research on three nonsurgical alternatives - osteoplasty, radiofrequency ablation and cryoablation - to reducing pain relief caused by bone tumours were presented at the SIR annual meeting.

Bone tumours, or bone metastases effect more than 60% of patients with advanced cancer, when the cancer metastasizes to the bone. The terrible pain is generally not treated with surgery, which would require an extensive procedure and recovery time, but with narcotics and - if the latter is not effective - radiation treatments.

While radiation reduces pain in approximately 70% of patients, pain often returns or increases over time. Further radiation therapy is often not possible because it would damage healthy tissue. In addition, radiation therapy often takes five to 20 weeks to work. The new non-surgical techniques presented at SIR either heat or freeze the tumour, which kills the tumour and nerve endings in the vicinity of the metastasis, that were causing pain.

Dr Mathew Callstrom of the Mayo Clinic, Rochester, Minnesota, presented the interim results of an ongoing clinical trial using image-guide percutaneous cryotherapy to treat bone metastases.

Cryoablation targets tissue by freezing it with extreme cold produced by Argon gas in a sealed probe, while sparing the healthy tissue. The interventional radiologist uses CT and ultrasound imaging to guide up to eight probes through the skin into the tumour, under anaesthesia. The "ice ball" that is created around the probe, visible with CT imaging, grows in size and destroys the frozen tumour cells.

While cryoablation is not a new procedure, in the last few years probes have become small enough and sufficiently insulated to be used by interventional radiologists through a small nick in the skin.

In a media presentation at SIR, Callstrom said the procedure offered significant pain relief and improved quality of life within the first 24 hours. Of the 10 patients who have completed the 24-week follow-up, 80% had an average 74% reduction in their worst pain. The study is ongoing and a total of 30 adult patients are planned for enrolment.

Atsuhiro Nakatsuka of the school of medicine, Mie University, Japan discussed radiofrequency ablation (RFA), which sees heat delivered directly into the tumour via a probe. From the tip of the needle, radiofrequency energy is transmitted into the targeted tissue, where it produces heat and kills the tumour.

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Nakatsuka's study showed pain relief was achieved within a week for all of the 11 patients who underwent RFA. According to the visual analogue pain scale (VAS), patients' pain was reduced by two or more points on a 10-point scale. The mean VAS score decreased dramatically from 6.4 to 0.7. No patients experienced local recurrent pain during the mean follow-up period of five months. Nakatsuka and colleagues concluded RFA was effective in reducing pain, although when the tumour was adjacent to the spinal cord there was a risk of nerve injury.

Dr Anthony Ryan of Vancouver General Hospital, Vancouver, Canada presented on osteoplasty - an established technique used to treat painful vertebral metastases or fractures in the spine from osteoporosis now being used by interventional radiologists on other bones. Medical-grade bone cement is injected into the tumour, which gives off heat when mixed which kills the tumour before hardening to reinforce weakened bone that otherwise would be susceptible to fracture. Tumours often eat away healthy bone, and in weight-bearing bones this technique can be particularly useful because it can prevent fracture.

The interventional radiologist inserts a needle through a small incision above the affected bone, directing it under fluoroscopy (continuous X-ray imaging) into the tumour. The physician then injects a medical-grade bone cement which hardens in about 15 minutes.

Ryan's study concluded osteoplasty was a safe and effective treatment for unremitting cancer pain and gives prompt and dramatic pain relief and return to function. The study was a case series of patients treated with this technique at one hospital. Three men and two women were treated for malignant disease, and two women and one man for benign disease, for a total of eight patients. The treatment was successful in all eight patients, who experienced prompt and lasting pain relief. Additionally, there were no significant complications.