Abstract Background. Invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) are histologically distinct breast cancer subtypes. While ILC and IDC have similar disease-free survival (DFS) and overall survival (OS), the patterns of metastatic recurrence are suspected to differ due to differing adhesion markers. Methods. Retrospective review of a cohort of breast cancer patients treated at a tertiary academic medical center from May 1999 to April 2012 was performed. Demographic, pathologic, treatment and follow-up data were collected from a cancer database and the institutional medical records. Results. There were 179 ILC and 358 IDC (1:2 stage-matched) patients in the study period. Mean age (59 vs. 58 years), gender, race (88% vs. 80% Caucasian), menopause state (71% vs. 66% post-menopausal), and family history (48% vs. 42% positive for breast cancer) were similar in the two groups. Median follow-up was 4.7 years. ILC patients had more negative mammograms upon diagnosis (6.8% vs. 1.4%, p = 0.001), and their breast cancers were more likely to be hormone-receptor-positive/HER2-negative (90% vs. 69%, p < 0.00001). The recurrence rate was the same between ILC and IDC. ILC recurred more often in the abdominal cavity (24.3% vs. 4.1%, p = 0.001), and it recurred similarly to IDC in other sites (bone, lung, liver, central nervous system, and local). Both groups received similar treatments, including number of surgical resections (1.3), positive margins (17%), breast-conservation rate (42% in ILC vs. 49% in IDC), systemic treatment (91% vs. 88%), and taxane use during chemotherapy (71% vs. 69%). The DFS (10.6 vs. 11.4 years), OS (10.2 vs. 11.9 years), and breast-cancer-specific OS (11 vs. 13 years) were not statistically different. In a subgroup analysis, stage IV ILC patients had worse overall survival than stage IV IDC patients (2.9 vs. 6.8 years, p = 0.039). On multivariate analysis, age, stage of disease, hormone receptor status, and systemic therapy were associated with survival, but histology was not. Conclusions. Compared to ductal breast cancers, lobular breast cancers recur more often in the abdominal cavity. Both ILC and IDC have comparable surgical and medical treatment outcomes, including resection number, positive margin of resection, breast conservation rate, recurrence rate, and survival. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-07-11.