Lobular Breast Cancer: Same Survival and Local Control Compared with Ductal Cancer, but Should Both Be Treated the Same Way? Analysis of an Institutional Database over a 10-Year Period

Background. Invasive lobular carcinoma (ILC) is believed to be more often multicentric and bilateral compared with invasive ductal cancer (IDC), leading clinicians to pursue a more aggressive local and contralateral approach. Methods. Retrospective review of a consecutive cohort of breast cancer patients operated at one institution from January 2000 to January 2010 was performed. Median follow-up was 4 years. Results. There were 171 ILC (14.5%) and 1,011 IDC patients in the study period. Median age (63 vs. 65 years) and tumor diameter (1.7 cm) were similar in the two groups. Diagnoses of ILC were more frequent in the second half of the study period (55/465 vs. 116/662, p < 0.01). Multicentricity was reported in 108/1,011 (10.6%) IDC and in 31/171 (18.1%) ILC patients (p < 0.01). A positive margin of resection at initial surgery was documented in 71/1,011 (7%) IDC and in 21/171 (12.3%) ILC patients (p < 0.001). Although the rate of mastectomy decreased over time in both groups, this was more pronounced for ILC patients (p < 0.001). Locoregional control, contralateral cancer, overall survival, disease-free survival, and survival according to diameter, nodal status, and type of surgical intervention did not differ between IDC and ILC. On multivariate analysis, stage of disease and hormone receptor status were associated with disease-free survival, but histology was not. Conclusions. Although ILC is more often multicentric, bilateral, and associated with a positive margin of resection, local control and survival are similar to IDC. ILC can be treated similarly to IDC with good results.