My research has focused on a number of areas including the identification of risk factors for local and distant failure in patients with invasive cancer treated with conservative surgery and radiation therapy and the identification of patients with invasive cancer who may be adequately treated with excision alone. I have also been actively involved in the identification of risk factors for local recurrence in patients with ductal carcinoma in situ treated with breast conserving therapy. In addition, in collaboration with investigators in the Nurses' Health Study, I have been investigating the relationship between benign breast disease and breast cancer risk. Finally, I have been actively involved in evaluating the relative merits of immunohistochemistry and fluorscence in situ hybridization for the evaluation of HER2/neu status in breast cancer.