Dr. Stephen Ward of Good Hope Hospital in Sutton Coldfield, England, and colleagues studied 303 women who had breast-conserving surgery at the hospital from 2002 to 2008.
"Breast-conserving surgery followed by radiotherapy is a well-established alternative to breast removal and studies have demonstrated similar survival rates in patients undergoing these procedures," Ward, the lead author, says in a statement. "However patients undergoing breast-conserving surgery are more likely to have recurrent cancer and the amount of tissue removed around the tumor, known as the free margin, remains controversial."
The researchers studied 139 samples from 93 patients. Of these, 52 samples were from patients who had received surgery for non-invasive cancer, and 87 from patients who had had invasive cancer, where the cancer had spread to the surrounding breast tissue.
The study, scheduled to be published in the November issue of the International Journal of Clinical Practice, found women who received surgery for invasive cancer, the amount of residual disease -- defined as the presence of invasive or non-invasive cancer -- reduced from 35.3 percent with no margin to 2.4 percent with a margin of more than 2 millimeters.