Re-excision operations in nonpalpable breast cancer.

We retrospectively reviewed the records of 317 needle-localization (NL) biopsies performed at the Royal Marsden Hospital during 1989-1992. The malignancy yield in our centre, where there is an emphasis on cooperation with an experienced radiologist and breast pathologist, was 48% (151/317), with benign to malignant biopsy ratio of 1:1:1. Analysis of the histopathological findings of the malignant lesions revealed a 45% (68/51) incidence of positive microscopic margins. Of these 68 patients, 50 had re-excisions, including nine patients who required mastectomy. Twenty-eight of the re-excisions (56%) contained residual tumour, of which five (18%) were invasive carcinoma > 3 mm (size range 1-19 mm) and 13 (46%) were residual DCIS > 1 mm (size range 1-40 mm). Our findings suggest a significant incidence of residual disease associated with positive microscopic margins in NL-detected nonpalpable cancers. Therefore, our current practice of performing a wider re-excision for positive margins is justified. Stereotactic fine-needle aspiration cytology was not performed by the radiologist referring these cases, but it should be performed preoperatively and if the test is positive, definitive treatment in the form of wide local excision or quadrantectomy is carried out in the first instance in order to avoid a second-surgical procedure.