A clinical trial, led by a radiation oncologist at the Kimmel Cancer Center at Jefferson, was recently presented at the annual meeting of the American Society of Clinical Oncology (ASCO). The trial found that using ultrasound beams to heat and destroy tumors in bone reduced cancer-related pain for two out of three patients.
For people whose cancer has spread to their bones, radiation therapy is often used to reduce the pain. But in those patients who do not benefit from radiation, magnetic resonance image-guided focused ultrasound ablation therapy is an effective second option.
The ExAblate device uses numerous small ultrasound beams designed to converge on a tumor within the bone, heat it and destroy it.
“Pain is a common, often debilitating symptom of the spread of cancer to bones,” says Mark Hurwitz, MD, Director of Thermal Oncology for the Department of Radiation Oncology at Thomas Jefferson University and Hospital, who led the study. “We are pleased to now have a second therapy that can improve a patient’s enjoyment of life.”
Certain cancers including breast, prostate, lung and kidney cancers are more likely forms of the disease to spread, or metastasize, to the bones. Many of those patients can live for years, but the quality of their lives is impacted by the pain.
“The treatment is given just once, and a response occurs within days,” says Dr. Hurwitz. “There are a lot of patients who could potentially benefit.”
The findings of the trial led to approval of ExAblate last October by the U.S. Food and Drug Administration as second-line therapy for palliation of painful metastatic bone tumors. The first-line therapy is typically radiotherapy.
“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.
He added that use of ExAblate offers several advantages compared to other ablative therapies.
“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,” Dr. Hurwitz says. “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.”
The study led by Dr. Hurwitz is a multicenter, randomized and placebo-controlled phase three clinical trial. The 142 patients enrolled could either not undergo, or had not responded to, radiation treatment.
Three months after ExAblate therapy, 67 percent of treated patients reported significant improvement in pain, compared to 21 percent in the placebo arm. They typically rated their pain as “much improved” or “very much improved,” Dr. Hurwitz says. A quality of life assessment also measured significant improvement.
The clinical trial was sponsored by Insightec Ltd., who developed ExAblate.