A new procedure recently approved by the Food and Drug Administration to treat cancer pain significantly reduced pain in about two out of three patients with bone cancer, according to a new study presented this week at the annual meeting of the American Society of Clinical Oncology.
The procedure uses magnetic resonance imaging (MRI) to guide a focused beam of acoustic energy through the patient’s skin, muscles and tissue to heat the targeted bone area. The increase in temperature destroys the periosteum, which contains the pain-reporting nerve fibers.
Mark Hurwitz, MD, Director of Thermal Oncology at Thomas Jefferson University and Hospital, reported that the treatment significantly reduced pain in 67 percent of patients who received it during a clinical trial.
“Pain is a common, often debilitating symptom of the spread of cancer to bones. We are pleased to now have a second therapy that can improve a patient’s enjoyment of life,” said Dr. Hurwitz, who led the study of 142 cancer patients who did not respond to radiation treatment to control their pain or were unable to have it.
Patients with cancer that has spread to their bones are often treated with radiation therapy to reduce pain. But if that treatment doesn’t work, which happens about 30% of the time, they now have a second option. Last October, the FDA approved the use of the MRI guided device, called ExAblate, as second-line therapy for palliation of metastatic bone tumors.
“The response to ExAblate was as good as radiotherapy, which was notable because it is very unusual to see a second-line treatment with a response rate that is as high as first-line therapy,” Dr. Hurwitz says.
“It is non-invasive and provides more detailed anatomic information so that we can visualize the complete beam path to make sure that critical structures such as vessels and nerves are not in the way. We are also able to monitor the temperature in the tumor as well as in nearby normal tissues so that we do not inadvertently heat normal organs and tissues.”
Over two-thirds of breast and prostate cancers that metastasize spread to the bones, according to the American Cancer Society. Bone metastases also occurs in up to 30% of metastatic lung, bladder and thyroid cancers. Many patients can live for years with painful metastases, which can have a profound impact on a patient’s quality of life.
Three months after ExAblate therapy, 67% of treated patients reported their pain was pain was “much improved” or “very much improved,” compared to 21% who had a placebo treatment. A quality of life assessment also measured significant improvement for ExAblate patients.
“The treatment is given just once, and a response occurs within days,” Hurwitz said. “There are a lot of patients who could potentially benefit from MR guided focused ultrasound.”
The ExAblate device is made by InSightec, an Israeli manufacturer.
Focused ultrasound surgery is a relatively new medical technology being developed to treat cancer and other diseases. In the U.S. it is still only approved as therapy for uterine fibroids and pain from bone metastases; but trials are underway for its use in the treatment of breast, brain, prostate and liver tumors.