The Northeast Wisconsin Cancer Registry and a patient survey was utilized to examine the use of breast conservation surgery in Brown County between 1991 and 1997 and the factors influencing patients' treatment decisions. In all patients, the rate of breast conservation rose from approximately 30% to 44% during that time period. The percent of all patients with stage 0, I or II breast cancer who were potential candidates for breast conservation based on their stage rose from 89% in 1991 to 96% in 1997. The percent of Stage I and Stage II patients who underwent breast conserving surgery rose from 29% in 1991 to 38% in 1997. There was a higher use of breast conserving surgery in younger women (approximately 50% in age 35 to 49 years old in 1997) compared to women older than 62 (33% in 1997). Breast conservation surgery was used in 47% of patients with AJCC T1 (primary tumors less than 2 cm) and in 25% of patients with T2 lesions (primary tumors 2 to 5 cm); and more often in node negative than in node positive patients (51% vs. 20%). A patient survey revealed that a majority of patients felt that their surgeon's recommendation was the most important influence in making their surgical decision and that their fear of cancer recurrence most strongly influenced their decision on a personal level. Fewer than half of the women were referred to a medical oncologist, radiation oncologist, plastic surgeon or second opinion surgeon prior to surgery. Breast conservative treatment is increasingly utilized in Northeastern Wisconsin and women depend on their surgeon to give them clear, complete, non-biased information balanced with emotional support during the time when they are asked to make the complex decision of the type of breast cancer surgery they desire.