Surgical removal of breast cancer is a compromise between excision of the tumour and cosmetic and other deficits induced.
Adequate removal is accomplished by clearance of all neoplastic (defective) cells, but since these growths are irregular and not visible to the naked eye, we like to allow a margin of at least 1 mm (one sixteenth of an inch) all the way around, leaving the remainder of the breast. This is called conservation surgery or a Wide Local Excision (WLE).
Unfortunately this leads to an increased local recurrence rate unless accompanied by a course of local radiotherapy. Consequently the surgical decision involves this treatment from an oncologist, lasting about five weeks, to control local cells that may have escaped surgery. The package of WLE surgery and radiotherapy produces similar survival results to mastectomy.
Not everybody is suitable for conservative surgery, the decision depends on the size and situation of the tumour. In rare instances it may be possible to shrink the tumour first with chemotherapy or hormone therapy to permit WLE, but these are complex circumstances.
A common complication of WLE (10 to 20%) is that the tumour is inadequately excised at the first attempt, and further surgery would then be necessary.