“When you take out the high-risk group, the data actually look a lot better,” she said.
A separate randomized British trial of intraoperative radiation therapy produced similar overall results in 1,721 patients, but two-thirds of patients would be considered unsuitable or cautionary in the United States, Dr. Vito said (Lancet 2014;383:603-613).
Overall survival and breast cancer survival were similar in the intraoperative and whole-breast radiation groups except for worse outcomes in patients who had intraoperative radiation done as a second surgery after the operation to perform lumpectomy.
The rate of deaths from causes other than breast cancer was higher in the whole-breast radiation group, in many cases due to cardiac events, Dr. Vito noted. Whole-breast radiation on the left side of the chest has been shown to accelerate atherosclerosis of the vessels in the heart, and it may be that avoiding this through intraoperative targeted radiotherapy may provide a cardiovascular benefit, though this is yet to be proven, she added.
A separate presentation at the meeting explored the increasing rate of women with cancer in one breast who choose prophylactic mastectomy of the healthy contralateral breast. The rate of prophylactic contralateral mastectomy increased 150% between 1998 and 2003 in the United States, from 1.8% to 4.5%, Dr. Swati Kulkarni said.
She and her associates surveyed a diverse cohort of 150 women before surgery for cancer in one breast and again 6 months after surgery. Only 14% said that medical staff had provided information about removing the healthy breast along with the cancerous breast; 63% said they did not get that information, and 23% were unsure, reported Dr. Kulkarni of the University of Chicago.
Dr. Swati Kulkarni
Thirty-nine percent of patients had thought about their surgical choices before they were diagnosed with breast cancer, and 58% of the cohort wanted or considered contralateral prophylactic mastectomy.
Patients with a family history of breast cancer who had undergone genetic testing were significantly more likely to want or consider prophylactic contralateral mastectomy. Factors that were not significantly associated with prophylactic contralateral mastectomy were family history by itself, age, race, insurance status, cancer stage, use of breast MRI, or having one or more biopsies.
The findings suggest that education about prophylactic mastectomy is needed “inside and outside of the doctor’s office,” Dr. Kulkarni said.
The speakers reported having no financial disclosures.
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