A new research has revealed that removing an extra two millimetres around an area of invasive breast cancer is sufficient to minimize any residual disease in 98 per cent of patients.
Surgeons from the Department of Breast Surgery at Good Hope Hospital, Sutton Coldfield, UK, studied 303 women who had undergone breast-conserving surgery at the hospital between 2002 and 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," said lead author Stephen Ward.
"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.
"A survey of 200 UK breast surgeons published in 2007 revealed wide variations in what they considered to be an adequate margin, with 24 percent wanting a clear margin of 1mm and 65 percent wanting a margin of 2mm or more," he said.
The Good Hope team carried out further excision specimens on 31 percent of the women who had received breast-conserving surgery to check for residual disease, obtaining 139 samples from 93 patients.
Of these, 52 samples were from patients who had received surgery for non-invasive cancer, where the cancer is confined to the milk ducts or lobules, and 87 were from patients who had had invasive cancer, where the cancer had spread to the surrounding breast tissue.
They found that in the women who had received surgery for invasive cancer, the amount of residual disease, defined as the presence of invasive or non-invasive cancer, reduced as the free margin increased - from 35.3 percent with no margin to 2.4 percent with a margin of more than 2mm.
However, when it came to the women who had received surgery for non-invasive cancer, residual disease was higher and the pattern was less than clear. Incidence ranged from 0percent at more than 5mm to 57 percent when the margin was between 0.1 to 0.9mm, but 44 percent where no margin was involved.
The research team also looked at the characteristics of the 202 women who had a close free margin of less than 2mm and the 101 women who had had a clear free margin of 2mm or more.
They found that women with a close margin of less than 2mm were more likely to be associated with large grade three tumors than the clear margin group and with lymphovascular invasion and nodal involvement.
The findings were published in the International Journal of Clinical Practice.