Clinicopathologic significance of ductal carcinoma in situ in breast core needle biopsies with invasive cancer

To assess whether the presence and amount of intraductal component (IC) in diagnostic needle core biopsies (NCB) is predictive of an extensive IC (EIC ), the authors evaluated 50 invasive ductal carcinomas diagnosed with NCB, and then excised via lumpectomy, with regard to the extent of IC in both th e NCB and subsequent lumpectomy specimen. These parameters were compared wi th each other and with the lumpectomy margin status. Extent of IC in the NC B was evaluated by dividing the number of ducts that contained IC by the to tal number of tissue cores. A ratio of more than 0.5 was considered EIC (EI CC). IC extent in the lumpectomy was established by estimating the percenta ge of the tumor corresponding to IC and was considered extensive (EICL) if more than 25% and if there was presence of IC away from the invasive tumor. The mean size of resected tumors was 1.6 +/- 0.7 cm. In 29 cases (58%) the re was no IC in the NCB (NegIC(C)), 11 cases (22%) exhibited nonextensive I C (NEICC), and 10 cases (20%) demonstrated EICC. A total of 7%, 36%, and 70 % of the NegIC(C), NEICC, and EICC cases respectively had EICL (p < 0.0001) . The presence of EICL correlated significantly with close or positive marg in status for in situ disease (EICL positive, 12 of 13 [92%] vs EICL negati ve, 11 of 37 [30%]; p = 0.004). None of the NegIC(C), 27% of NEICC, and 40% of EICC had a positive margin for in situ neoplasm in the lumpectomy speci men (p = 0.004), and 24%, 18%, and 50% had positive margins for invasive ne oplasm (p = not significant). The authors conclude that EICC predicts EICL and constitutes a risk factor for positive lumpectomy margin status-particu larly for in situ tumor. EICC may thus be of clinical value in identifying a subset of patients that requires a wider local excision.