The role of clinical trials in changing therapy for ductal carcinoma in situ.

Abstract

Some aspects of the diagnosis of ductal carcinoma in situ (DCIS) are well established, but consideration of other variables may be critical to optimize treatment. Mastectomy was once standard surgery, to reduce the probability of invasive breast carcinoma recurrence (to < 1%). However, the ability to control DCIS to a comparable extent but without resorting to mastectomy has been a major goal. There are indications from clinical studies that excision plus radiation therapy is as effective as mastectomy in reducing recurrence in patients with low-risk DCIS. Furthermore, following surgery and irradiation with long-term endocrine therapy appears to further reduce the risk of local DCIS progression. Variables that should be considered in making a treatment decision are extent of disease within the breast, nuclear grade of the lesion, age of the patient, and margin of surgical excision. Several randomized trials are currently evaluating the clinical value of these variables in optimizing treatment for patients with low-risk DCIS. Future improvements in treatment may depend on more sophisticated cellular and molecular markers of disease extent and prognosis at diagnosis.