Ever since the 1970's, when lumptectomy was shown to be as effective as mastectomy for treating early-stage breast cancer, surgeons have been stumped by one of the most vexing problems in oncology: how wide should the margins be around the tumor to insure adequate removal of the cancer so that the risk of local recurrence or, worse, distant metastatic spread can be driven down as low as possible?
Early on, the conventional...



