Damian Dupuy, MD and
William Mayo-Smith, PhD
Since 1997, Damian Dupuy, MD, director of ablation services at Rhode Island Hospital, has used image-guided radiofrequency ablation (RFA) to manage pain in bone cancer patients, with impressive results. Not only have patients experienced significant pain reduction from this minimally invasive procedure, many have also been able to avoid the side effects associated with heavy doses of narcotics for pain management. Dupuy, who also is a professor of diagnostic imaging at The Warren Alpert Medical School of Brown University, was principal investigator of a recent study sponsored by the National Cancer Institute that demonstrated the benefits of RFA for pain management in bone cancer patients.The results of the 55-patient study were published in the December 29, 2009 edition of the journal Cancer.
Dupuy worked in collaboration with Howard Safran, MD, medical oncologist; Thomas DiPetrillo, MD, radiation oncologist; and Wendy Smith and Cynthia Cobb, certified research associates, among others. Dupuy says, They saw all these very sick patients up front, helped with the consent process and followed them afterwards, because they had to fill out pain scales at various time points after the procedure.
Bone cancer is an extremely painful condition. What happens is that as the tumor grows, it causes an inflammatory reaction in and around the bone, which causes chemicals to be released that irritate the nerves, Dupuy says. It can cause pressure on the bone marrow, and there are nerves inside the bone cortex that feel that pressure. It's a kind of an unremitting pain that's constant.
Although radiotherapy and narcotics are available to cancer patients, certain cancers are resistant to radiation, and drugs may become less effective over time. Radiotherapy is the mainstay of treating bone pain in cancer patients.The problem is, radiation doesn't always work. So patients continue to use higher and higher doses of narcotics, which reduce their quality of life. It may reduce their pain, but they can't interact with people, and they certainly can't work.
Because time with friends and loved ones may be very limited, quality of life is especially important for bone cancer patients. I would say the vast majority of people we treat have less than a year to live, Dupuy estimates. However, I have several patients who were in this trial who are still alive four years later.
During the procedure, a needle-like electrode, similar in gauge to a biopsy needle, is placed into the tumor. An electrical current, in the frequency of radio waves, is applied. The electrons coming through the needle bounce into the molecules in the tissue at the tip of the electrode, producing frictional heat. That heat actually cooks the tissue inside the patient. By cooking the tissue, and some of the inflammatory tissue around it, you essentially deaden the nerves and reduce some of the mass effect that the tumor has on the adjacent structures, Dupuy says. The procedure itself takes about two hours. It's performed in a single outpatient visit, Dupuy says, with intravenous conscious sedation, and they go home the same day with a band-aid on their skin.
The study, which was supported by the American College of Radiology Imaging Network, showed statistically significant pain reduction at the one- and three-month follow-up examinations for pain relief, intensity and severity. In all cases, the patient's mood improved.
Dupuy expects that the next step could be to do a comparison with radiation, which is the standard therapy. There also are people using freezing to treat bone tumors, so we could do a comparison with freezing, looking at the differences in efficacy. In addition to the search for cures, Dupuy and his colleagues will continue investigating the best ways to ease pain and improve quality of life for patients with very challenging illnesses.