Six of the Best, Breast 10

Aims: Stereotactic core biopsy has resulted in an increased preoperative diagnosis of DCIS and has replaced wire-localized open biopsy for screen-detected microcalcification, potentially reducing the need for reoperation to obtain clear excision margins. Our aim was to assess the impact of the introduction of stereotactic core biopsy on the reoperation rate for screen-detected impalpable DCIS. Methods: A retrospective analysis was performed on a cohort of 221 women with screen-detected pure DCIS with (after 1997, n = 74) and without (before 1997, n = 147) a preoperative core biopsy diagnosis. An intraoperative specimen X-ray was performed to assess the adequacy of excision. The two groups of patients were matched for age and DCIS nuclear grade. Results: Pathological and mammographic DCIS tumour sizes were similar (r = 0.71, P < 0.001). Conclusion: Changes from diagnostic to therapeutic primary operative excision for screen-detected DCIS have not resulted in a reduction in the total number of operations required to complete treatment, because mammography underestimates DCIS tumour size in 30 per cent of patients.