['Our aim was to determine if BRCA mutation status changes surgical decision making in women who undergo genetic testing after the diagnosis of breast cancer.', "This is a retrospective cohort study of breast cancer patients who had BRCA mutation testing performed prior to surgery. We compared surgical choice and change in surgical choice in women who tested positive for a BRCA mutation with those who tested negative. Surgery was considered the most definitive surgery within a year of diagnosis. Other data collected included age, race, stage, histology, receptor status, adjuvant treatment, gravity, parity, and family history. Variables were compared by BRCA status using Fisher's exact test and logistic regression.", 'Three hundred and two women were included. Thirty-two (10.6%) were identified as carrying a BRCA mutation. Most women had early stage disease (55.6% T1 lesions, 72.8% node negative); 55.6% had breast-conserving surgery, and the remaining had unilateral or bilateral mastectomy. BRCA mutation carriers were more likely to have both a personal history of breast cancer (RR 2.74, 95% CI=1.08-6.98) and hormone receptor-negative tumors (56.0% vs. 26.2%, p=0.002). BRCA mutation carriers were more likely to choose bilateral mastectomy with reconstruction (56.3% vs. 15.9%, p<0.0001); 71.9% of BRCA mutation carriers opted for a different surgery than what was initially planned by their surgeon as compared to 29% of mutation-negative patients (p<0.0001).'] Does preoperative genetic testing affect surgical decision making in breast cancer patients?