CHICAGOAmong patients with intractable and severe pain because of bony metastases, radiofrequency ablation either relieved pain completely or produced a significant reduction in patients’ assessment of pain, according to a study presented at the 88th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA abstract 228VI-p). In this multicenter study of 62 patients with osteolytic metastases, 44% reported they were completely free of pain at some point during the 6 months following radiofrequency ablation, 81% had a 3-point drop in the Brief Pain Inventory (BPI), and 95% had at least a 2-point drop in BPI.
"Many studies have shown that a drop in pain score of 2 points is significant. We are seeing drops of 4 points, which is a very large decrease in patients who really have no alternatives," said Matthew R. Callstrom, MD, PhD, assistant professor of radiology, Mayo Clinic, Rochester, Minnesota.
One patient with rectal carcinoma that had spread to the sacrum was unable to sit upright or lie down before radiofre-quency ablation. Immediately after initial treatment, which involved seven separate needle placements in the inferior portion of the lesion, his mean pain score dropped from 8 to 3. After further ablation of the upper portion of the sacral lesion, the mean pain score dropped to 0, and he experienced no other pain during 6 months of follow-up.
"The critical thing here is that the patient went from high doses of narcotics and no other optionshe had explored radiation and chemotherapy, but nothing workedto a very effective treatment. This was able to take away his pain," Dr. Callstrom said.
Radiofrequency ablation spared a 29-year-old woman with metastasis to the shoulder four-quarter amputation. Among seven patients who died during the follow-up period, the procedure produced such a significant reduction in pain that four patients were able to spend their last months enjoying time with their families without being totally obtunded by narcotics, Dr. Callstrom said.
In addition to pain relief, the study showed that radiofrequency ablation is safe. There were four major complications followed radiofrequency ablation of osteolytic lesions. One patient sustained a fracture of the hip 6 weeks after treatment. The patient already had a large destructive lesion in the area of the fracture, so it was not clear if the fracture was due to radiofrequency ablation or would have occurred eventually anyway. Three other patients had tumor extending through a fistula below the level of the tailbone. An additional patient developed minor bowel and bladder incontinence, which resolved over a number of weeks.
As Dr. Callstrom explained, radiofrequency ablation delivers high-frequency energy via an electrode that is placed in a lesion to destroy cancer cells and in the process alleviate pain. The radiofrequency device, which is inserted through a small incision in the skin, deploys a series of tines into a lesion under guidance by CT or ultrasound and directs current into targeted areas around a metastatic lesion for 5 to 10 minutes.