Intraductal carcinoma of the breast: pathologic features associated with local recurrence in patients treated with breast-conserving therapy.

Local excision and radiation therapy is a standard treatment option for duct carcinoma in situ (DCIS) of the breast. There is no consensus regarding the significant histologic features associated with recurrence. The authors studied a large group of patients with mammographically detected DCIS treated with breast-conserving therapy to explore DCIS volume relationships, DCIS features, specimen characteristics, and the effect of patient age at diagnosis. Thirteen patients (10%) developed a recurrent carcinoma in the ipsilateral breast, resulting in 5- and 10-year actuarial recurrence rates of 8.9% and 10.3%, respectively. Local recurrences were identified as a true recurrence/marginal miss (TR/MM) in nine patients, and elsewhere in the breast in four patients. The notable features associated with TR/MM recurrences on univariate analysis included patient age less than 45 years old, six or more slides with DCIS, no microscopic calcifications within DCIS ducts, and five or more DCIS ducts or terminal duct lobular units (TDLUs) with cancerization of lobules (COL) within 0.42 cm of the final surgical margin. DCIS tumor size, nuclear grade, amount of central necrosis, and margin status were not associated with outcome. Multivariate analysis found that the absence of microcalcifications within DCIS ducts, patient age, number of slides with DCIS or TDLUs with COL, and the number of DCIS ducts or TDLUs with COL within 0.42 cm of the final margin were related significantly to TR/MM recurrence. Patients with a total of six or more slides with DCIS, or who have 11 or more DCIS ducts or TDLUs with COL near the final margin are at increased risk of having a substantial volume of residual DCIS in the adjacent unexcised breast. These results suggest that the volume of DCIS in the specimen, and the volume of DCIS near the margin are associated with local recurrence. These features can be used to identify those patients with a higher chance of local recurrence.