Breast-Conserving Therapy for Ductal Carcinoma in Situ: The Van Nuys Experience with Excision Plus Radiation Therapy

Abstract: The incidence of ductal carcinoma in situ (DCIS) of the breast has increased significantly in the last 15 years paralleling increases in the use of screening mammography. During that time, breast-conserving therapy for DCIS has become an established treatment option for patients with DCIS. 185 patients with pure DCIS treated with excision and radiation therapy were studied. The risk of local recurrence increased as nuclear grade or the diameter of the primary tumor increased. It decreased as margin width increased. Tumors containing predominantly comedo histology had an increased local recurrence rate when compared with noncomedo lesions. There was no difference in local recurrence rates for patients treated 4 or 5 days per week. The median time to local recurrence was 53 months. At 12 years, the actuarial local recurrence rate was 24% for all patients. The breast-cancer specific mortality over the same 12 year period was 3%. The increasing incidence of DCIS necessitates that current treatment options undergo continuous re-evaluation. Although it is likely that selected subsets of low-risk patients can be adequately treated with excision and observation, it is equally likely that patients at high risk for local recurrence will require radiation therapy as part of their management if breast preservation is chosen. Our data suggests that histologic factors such as large tumor size, narrow margin width, high nuclear grade, and comedo architecture may aid in selecting which patients require the addition of radiation therapy to their treatment regimen and which patients do not if breast preservation is chosen.