The management of ductal carcinoma in situ of the breast

Ductal carcinoma in situ (DCIS) of the breast is a heterogeneous group of l esions with diverse malignant potential. It is the most rapidly growing sub group within the breast cancer family with more than 42 000 new cases diagn osed in the United States during 2000. Most new cases are nonpalpable and a re discovered mammographically. Treatment is controversial and ranges from excision only, to excision with radiation therapy, to mastectomy. Prospecti ve randomized trials reveal an approximate 50% reduction in local recurrenc e rate overall with the addition of radiation therapy to excisional surgery , but the published prospective data do not allow the selection of subgroup s in whom the benefit from radiation therapy is so small that its risks out weigh its benefits. Nonrandomized single facility series suggest that age, family history, nuclear grade, comedo-type necrosis, tumor size and margin width are all important factors in predicting local recurrence and that one or more of these factors could be used to select subgroups of patients who do not benefit sufficiently from radiation therapy to merit its use. When all patients with ductal carcinoma in situ are considered, the overall mort ality from breast cancer is extremely low, only about 1-2%. When conservati ve treatment fails, approximately 50% of all local recurrences are invasive breast cancer. In spite of this, the mortality rate following invasive loc al recurrence is relatively low, about 12% with eight years of actuarial fo llow-up. Genetic changes routinely precede morphological evidence of malign ant transformation. Lessons learned from ongoing basic science research wil l help us to identify those DCIS lesions that are unlikely to progress and to prevent progression in the rest.