How doctors choose to treat their breast cancer patients and whether those treatment choices follow established recommendations may play a larger role in whether a cancer returns than experts have believed. In a new analysis looking at 994 women with ductal carcinoma in situ, the most common type of noninvasive breast cancer, researchers found treatment variations from surgeon to surgeon are significant, and may account for up to 30 percent of recurrences.
"Treatment variation is a troubling but well-known phenomenon in health care," said study author Andrew W. Dick, a researcher at RAND Corp. in Pittsburgh. The report is published online Jan. 3 and in the Jan. 19 print issue of the Journal of the National Cancer Institute. "The reason it is surprising in this case is that the variation is quite large, and related to factors that are very important in health outcomes," Dick said.
Those factors include having "negative margins" meaning that cancer cells are more than 2 millimeters away from the removed tissue's edge and getting radiation therapy after breast-conserving surgery. The variation by surgeon in treatments accounted for 15 percent to 35 percent of cancer occurring in the opposite breast in the next five years and 13 percent to 30 percent of recurrences over 10 years, the investigators found.