FACTORS AFFECTING SURGICAL MARGIN CLEARANCE IN SCREEN-DETECTED BREAST-CANCER AND THE EFFECT OF CAVITY BIOPSIES ON RESIDUAL DISEASE

One hundred and fourteen localization biopsies for screen-detected bre ast cancers were assessed for surgical margin clearance and presence o f tumour in the cavity biopsies or subsequent resections, Inadequate s urgical clearance (less than or equal to 1 mm from the margin) in 88 p atients was associated with high nuclear grade ductal carcinoma in sit u, or extensive in-situ change accompanying invasive carcinomas, vs pu re invasive carcinomas. Smaller localization biopsies (less than or eq ual to 50 g), larger tumours, and absence of a definite fine-needle as piration cytological diagnosis of malignancy were also associated with inadequate excision, The radiographic characteristics of the tumours did not correlate with inadequate excision. Sixty-five patients had ca vity biopsies taken at the time of surgery and 23 (35%) biopsies were positive, 20 of which were associated with incompletely excised tumour s. Further excision in 78 patients yielded residual disease in 63%, mo st of whom had had inadequate surgical clearance. When cavity biopsies were taken with incompletely excised tumours, 15 of 88 subsequent res ection specimens harboured residual disease compared with 29 of 88 wit hout cavity biopsies, Although cavity biopsies increase the clearance margin, a negative cavity biopsy is not always an assurance of adequat e excision.