A mass on breast imaging predicts coexisting invasive carcinoma in patients with a core biopsy diagnosis of ductal carcinoma in situ

An image-guided core-needle breast biopsy (IGCNBB) diagnosis of ductal carc inoma in situ (DCIS) is often upgraded to invasive carcinoma (IC) after com plete excision. When IC is identified after excision patients must be retur ned to the operating room for evaluation of their axillary nodes. We perfor med this study to identify histologic or mammographic features that would p redict the presence of invasion when DCIS is documented by IGCNBB. Patients with an IGCNBB diagnosis of DCIS were identified from a prospective databa se. Imaging abnormalities were classified as either calcification only or m ass with or without calcifications. IGCNBB specimens were reviewed to docum ent nuclear grade and the presence of comedo-type necrosis, periductal fibr osis, and periductal inflammation. Patients were divided into two groups, D CIS and IC, on the basis of the final diagnosis after complete excision. Fr om July 1993 through May 2000, 148 of 2995 (4.9%) IGCNBBs demonstrated DCIS ; eight were excluded after pathologic review. Of the remaining 140 patient s 36 (26%) demonstrated IC after complete excision. The presence of a mass on breast imaging was the only significant predictor of IC (P=0.04). On the basis of the results of this study we now perform sentinel lymph node mapp ing and biopsy at the initial surgical procedure for patients with an IGCNB B diagnosis of DCIS and an associated mass on breast imaging.