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Researchers at the University of Oklahoma (OU) have been investigating focused microwave thermotherapy (FMT), a microwave treatment capable of destroying large cancer tumors in patients with breast cancer. They reviewed data from four multi-institutional studies and found that when administered with neoadjuvant chemotherapy, FMT reduced the need for mastectomies by ~90% in women with invasive carcinomas. “This therapy is a major advancement for women with later stage breast cancer. Right now, most patients with large tumors lose their breast. With this treatment along with chemotherapy, we were able to kill the cancer and save the breast tissue,” said William Dooley, MD, researcher at the OU Cancer Institute and the director of surgical oncology at OU Medicine, in a press release.
The FDA-approved technique adapts the microwave technology behind former President Ronald Reagan’s “Star Wars” defense system. In a phase I study involving 10 patients with breast cancer, a single dose of FMT produced tumor shrinkage in 8 patients. Another study randomized patients with early stage invasive breast cancer to FMT at ablative temperatures prior to breast conserving surgery (n = 34) or to breast conserving surgery alone (n = 41). None of the patients treated with FMT had positive tumor margins compared with 4 patients in the group that did not receive FMT (P = .13). Another study randomized patients with large tumors ranging from 1 to 1.5 inches, which ordinarily necessitate mastectomy, to FMT within 2 hours of receiving neoadjuvant chemotherapy or chemotherapy alone. Median tumor volume was reduced by 88.4% (n = 14) for patients in the FMT arm compared with 58.8% (n = 10) for the chemotherapy-only group (P = .048). The percentage of patients requiring mastectomies declined from 75% to 7%. According to Dooley, FMT could theoretically be applied to any organ capable of being held “relatively still.”
Researchers hope to build on this breakthrough treatment by testing FMT on even larger tumors in the next phase of clinical trials, scheduled to start this year. “The trial was very successful. We were able to completely reverse those odds,” Dooley said. “We redesigned the machine and will begin clinical trials this year to determine whether the therapy works on tumors that are larger than 1.5 inches and smaller than 5 inches.”
The team wants to integrate heat-sensitive nanotechnology to target cancer cells more precisely. They also plan to study whether deposits of cancer proteins in the bloodstream following rapid tumor disintegration affect immune resistance to cancer recurrence. The study was published in Annals of Surgical Oncology
Dooley WC, Vargas HI, Fenn AJ, et al. Focused microwave thermotherapy for preoperative treatment of invasive breast cancer: A review of clinical studies. Ann Surg Oncol
. 2009. [Epub ahead of print.]