Factors associated with residual disease on re-excision in patients with ductal carcinoma in situ of the breast

PURPOSE: This study examines the factors associated with the presence of residual disease at re-excision in patients with ductal carcinoma in situ of the breast. METHODS: Of 143 consecutive patients undergoing breast conservation treatment from 1990 to 1999, 90 patients (63%) underwent re-excision of the tumor bed. Grade was recorded in 70% (N = 63), size in 78% (N = 70), margin status in 96% (N = 86), volume of excision in 90% (N = 81), and extent of residual disease in 99% (N = 89). RESULTS: There was no significant correlation between extent of residual disease on re-excision and method of detection, tumor size, histology, grade, or first margin status. Of patients undergoing re-excision, 56% (N = 50) had no residual disease, 38% (N = 34) had minimal microscopic residual disease, and only 6% (N = 5) had either extensive microscopic or gross residual disease. For these five patients, the median volume of first excision was similar to that of the other patients (26 vs 36 cc), but the median volume of second excision was smaller (33 vs 63 cc). The median age for these five patients was 41 years, compared with 55 years for the remaining patients. All five patients had comedo (N = 4) or solid tumor (N = 1) histology, with grade 3 (N = 3) or unknown grade (N = 2). DISCUSSION: Patients with extensive microscopic disease or gross residual at the time of re-excision would be at increased risk for local recurrence after conventional radiation treatment if re-excision had not been performed. Only 6% of patients in this study had such pathology findings. No factor predicted for these adverse pathology findings, although these patients tended to be younger, with high-grade or comedo histology.