When nothing else relieves severe cancer pain, freezing the tumors might help.
The strategy doesn’t cure cancer. Instead, it’s intended to ease the agony that terminally ill patients can feel when conventional treatments don’t work.
The method, called cryoablation (search), fared well when tried on four cancer patients. All were gravely ill with aggressive cancer that had returned or spread, and they were in severe pain that hadn’t responded to conventional treatments. Because of poor health and/or tumor location, surgery to remove the cancer and alleviate the pain wasn’t an option.
Doctors at Brown University inserted tiny instruments called cryoapplicators (search) through the patients’ skin, using CT imaging to guide the applicators to the tumors. The applicators quickly froze and thawed the tumors and surrounding area in one session, with each freeze-thaw cycle taking about 16 minutes.
The patients either had general anesthesia or sedation during the procedure.
The freezing process eases pain by killing cancer cells, small sensory nerve cells, and inflammatory tissue, says Damian Dupuy, MD, in a news release. Dupuy worked on the study with two colleagues from the diagnostic imaging department at Brown’s medical school.
Easing Patients’ Pain
All four patients had at least some improvement in their pain after cryoablation. Two patients — a 57-year-old man with rectal cancer that had spread and a 55-year-old woman with breast cancer that had spread — were pain free for at least a year since cryoablation, says the study.
The breast cancer patient had some nerve damage in her affected arm after cryoablation. Doctors had told her that that might happen, and she accepted that risk because she was in extreme pain. “She was aware of this possibility before the treatment and was pleased with the outcome,” says the study. The woman regained some nerve function in her arm, says Dupuy in the news release.
Another patient was a 20-year-old woman with a rare bone tumor called Ewing’s sarcoma that had returned. The tumor caused intense abdominal pain and limited her ability to walk. After cryoablation, she said she felt better and was able to walk four weeks after the procedure. She died a month later, having refused chemotherapy and radiation both times her cancer had surfaced.
The fourth patient was a 49-year-old man with colon cancer that had spread. A week after cryoablation, he said he could tolerate his pain better. However, he later needed more pain medicine and his tumor grew, leading to emergency surgery eight months after cryoablation.
Three of the four patients have since died, says the news release. That’s not unexpected since all were considered terminally ill. Cryoablation wasn’t designed to restore their health but to reduce their physical suffering. The one-time treatment gave them pain relief until death, says Dupuy in the news release.
Better Than Radiofrequency Ablation
Cryoablation has a couple of advantages over another method, called radiofrequency ablation, says the study.
While cryoablation uses cold, radiofrequency ablation employs warmth. It heats a small area with electrical current from a radio wave, reducing pain signals from that spot.
Cryoablation is less painful for patients and easier for doctors to use with CT imaging, write the researchers. CT images provide a real-time look at the treatment area. “We can watch the ice ball form on CT as it is being done to ensure the appropriate area is being treated,” says Dupuy in the news release.
Cryoablation was well-tolerated but needs testing on more people with longer follow-up, write the researchers, who are starting a new study of the procedure. Meanwhile, their first report appears in the March issue of the American Journal of Roentgenology.
SOURCES: Beland, M. American Journal of Roentgenology, March 2005; vol 184: pp 926-930. News release, American Roentgen Ray Society. WebMD Medical Reference provided in collaboration with The Cleveland Clinic: “Radiofrequency Ablation.”