Focused ultrasound under MR guidance may offer a safe and effective noninvasive treatment for breast cancer, according to research presented at RSNA 2013.
MR-guided focused ultrasound (MRgFUS) ablation requires no incision or puncture to perform. Instead, it uses the acoustic energy from high-intensity focused ultrasound to heat and ablate diseased tissue. Continuous MRI is used to locate the lesions and monitor the temperature change during the process. The primary potential advantages of MRgFUS over other breast cancer treatments are that it is a noninvasive, outpatient procedure offering a quick recovery time and precise measurement of temperature changes during the procedure.
“In the treatment stage, we are able to precisely visualize where the energy is having an effect and to measure exactly the rise in temperature,” said Alessandro Napoli, MD, PhD, an assistant professor of radiology at Sapienza University of Rome. “Temperature monitoring is particularly important, since too low of a temperature is ineffective and too high of a temperature may be dangerous.”
Napoli and colleagues assessed the safety and efficacy of MRgFUS in 12 patients with invasive ductal breast cancer before surgical removal of the cancer and biopsy of the lymph nodes. They used 3T MRI to confirm the presence and treatable location of cancerous lesions. The patients then underwent single-session MRgFUS treatment. Researchers evaluated treatment efficacy through postsurgery pathology.
None of the patients experienced significant complications during or immediately after the procedure. In 10 of the 12 patients, MRI showed no enhancement in the treatment area after the procedure. Postsurgery histological evaluation confirmed the absence of residual disease in the treatment area in those 10 patients. “This procedure allows for safe ablation of breast cancer,” Napoli said. “At pathology, no significant viable tumor was found in the specimens from these 10 patients.”
In the other two cases, treatment failed because of transducer malfunction, and the pathologist observed residual tumor in the samples.
According to Napoli, MRI guidance is crucial for correct identification of lesions, treatment planning, and real-time control during the procedure. Specifically, monitoring with MRI allows for efficiently depositing energy into the region of treatment at the correct range of between approximately 140˚ and 158˚F. “This is carried out by a special sequence that is called MR thermometry,” he said. “Only MRI presently has the ability to determine in real time fine temperature quantification.”
While the initial results are promising, Napoli cautions that more research will be needed before the approach can be adopted as a stand-alone treatment.
Source: Radiology Today
