Cancerization of Lobules and Atypical Ductal Hyperplasia Adjacent to Ductal Carcinoma In Situ of the Breast: Significance for Breast-Conserving Therapy

Recurrent carcinoma develops in approximately 10% of patients with ductal carcinoma in situ (DCIS) of the breast treated with local excision and radiation therapy. Cancerization of lobules (COL) and atypical ductal hyperplasia (ADH)frequently occur at the edge of DCIS. We postulated that recurrent carcinoma is associated with ADH or COL near the DCIS excision margin, and the amount of DCIS left in the breast may be too large for eradication by radiation therapy. To identify histologic features associated with recurrence, we retrospectively studied specimens of 94 patients with DCIS treated by local excision and radiation. We analyzed the rim of tissue near the final margin for the amount of COL, ADH, and DCIS. During a median follow-up of 78 months, local recurrence developed in 9 patients. COL or ADH with DCIS near the final margin was associated with recurrence; the strongest relationship was with recurrences in the same site as the lumpectomy bed. DCIS with ADH was significantly associated with recurrence in the low-grade DCIS group; DCIS with COL was associated with recurrence in the high-grade group. Other features were not associated with outcome. We believe that ADH composed of cells identified as those of DCIS should be considered part of the DCIS lesion. DCIS may be inadequately excised if ADH and DCIS or COL and DCIS are near the margin.