A single dose of radiation during breast cancer surgery is as effective as three to six weeks of daily post-operative radiation for many women with early stage breast cancer, according to the first results from an ongoing study of more than 2,000 women.
Most women undergoing a lumpectomy now have to visit a radiation center every weekday for at least three weeks following their surgery, a treatment that is, at best, inconvenient for working women and, at worst, debilitating for older ones. Many women also have to commute long distances to and from the radiation centers daily.
Some women elect a radical mastectomy instead of a lumpectomy so that they do not have to undergo the difficulties of daily radiation. The new results provide an alternative treatment and could reduce the costs associated with the procedure — as well as the long lines and waiting lists at some centers.
“We’re now getting really good long-term survival for breast cancer,” study coauthor Dr. Michael Baum of University College London said at a news conference Saturday at a Chicago meeting of the American Society of Clinical Oncologists. “The theme now is: How can we improve the quality of life for women?”
The approach relies on an electron-beam-driven device developed by Carl Zeiss Meditec of Jena, Germany. The device delivers a low dose of radiation to the area where the tumor has been excised; the 20- to 35-minute dose is administered before the wound is closed and while the woman is still under anesthesia. The Intrabeam device targets the immediate area of the excised tumor, where 90% of recurrences have been found to take place. Conventional radiation uses substantially higher doses and lasts from 30 seconds to several minutes each session.
The new study, led by Drs. Jayant S. Vaidya of University College London and David Joseph of the University of Western Australia in Perth, enrolled 2,232 women with early-stage breast cancer at 28 centers in nine countries. Half were randomly assigned to undergo the intraoperative procedure, and half surgery plus the conventional course of radiation. Baum presented the results at the oncologists’ meeting, and they were published online the same day in the journal Lancet.
The study was not blind: Researchers knew which patients received which treatment. It also established predefined criteria for women who underwent the Intrabeam therapy but who would also need conventional radiotherapy, such as the discovery that the women had lobular carcinoma, which arises from breast glands rather than ducts and thus requires more intensive treatment. About 15% of the women required such additional treatment.
After an average of four years of follow-up, the researchers observed the recurrence of tumors in six of the 996 patients who received the Intrabeam therapy and in five of the 1,025 who received conventional therapy. That translated to a recurrence rate of 1.2% in the Intrabeam group and 0.95% in the conventional therapy group.
The incidence of toxicity and complications were nearly identical in the two groups. The authors wrote that the device “almost completely avoids irradiation of the intrathoracic structures such as the heart, lung and esophagus. Consequently, the damage to these structures, which can occur even with modern external beam radiotherapy, will have been avoided.”
“This device truly revolutionizes patient management and the patient experience,” coauthor Dr. Laura Esserman of UC San Francisco said in a statement. “We have identified a subset of patients for whom it is safe, and we should ensure that all such patients can access this technology. We will continue to study this device in higher-risk patients to see if its role can be expanded.”
In an editorial accompanying the report in the Lancet, French researchers noted that longer-term results would be needed. Nonetheless, they said, in the elderly at the very least, combining surgery and radiation “is the new standard and intraoperative radiotherapy an excellent approach.”
The trial was funded primarily by the British and German governments, with some contributions by private organizations and Carl Zeiss Meditec.