Background: Mammographic screening for breast cancer facilitates earlier recognition of lesions, thus potentially allowing for breast-conserving surgery. Few studies have compared the final surgical outcomes of women presenting through breast screening programmes with those presenting via other sources. Are breast cancer patients presenting through BreastScreen more likely to undergo breast-conserving surgery than those presenting from other sources?Methods: Using the Royal Perth Hospital (RPH) Multidisciplinary Breast Service Database, the final surgical outcomes were reviewed for 723 women treated for breast cancer at RPH between January 2000 and August 2002. During this period, 397 patients were referred to the RPH Multidisciplinary Breast Clinic from BreastScreen WA, and 326 were referred from other sources.Results: Of all patients undergoing surgery for breast cancer, 58% in the screen group and 36% in the non-screen group had breast-conserving surgery (P < 0.0001). When surgical outcomes for women in the BreastScreen target age range of 50-69 years were analysed, 59.5% in the screen group and 42.3% in the non-screen group had breast-conserving surgery (P < 0.001). Patient choice was second only to disease extent as a factor determining the outcome of mastectomy. In both cohorts, more than 40% of patients who underwent re-excisional surgery for positive margins, after initial breast-conserving surgery, had residual invasive or in situ disease present.Conclusions: At RPH, BreastScreen patients were more likely to undergo breast-conserving surgery than those who presented from other sources. A significant proportion of women with positive margins after initial breast-conserving surgery had residual in situ or invasive disease. Re-excision for positive margins was thus warranted.