The study encompassed the time period January 1980 through December 2004. During this time 9485 women underwent mastectomy, 6847 women underwent breast conserving surgery (BCS) and 2477 women underwent breast radiotherapy (RT) for breast cancer. Linear regression modeling was used to quantify the rate of change in the proportion of women undergoing mastectomy during specific time periods. Chi-square tests were used to compare the proportion of women with a breast cancer less than 3 cm in size undergoing mastectomy the year prior to and the year after a specific event. There was a significant decrease in the number and proportion of mastectomies performed, an increase in the number of BCS procedures performed and an increase in the number of women undergoing breast RT around the times of (1) the employment of a young surgeon trained in BCS, (2) publication of the NIH Consensus Statement and (3) establishment of a multidisciplinary Breast Clinic.