Patients with Invasive Lobular Breast Cancer Are Less Likely to Undergo Breast-Conserving Surgery: A Population Based Study in The Netherlands

The aim of this study was to compare the frequency of breast-conserving surgery (BCS) between early-stage invasive ductal (IDC) and invasive lobular breast cancer (ILC). Women with primary non-metastatic pT1 and pT2 IDC or ILC diagnosed between 1990 and 2010 were selected from the NCR. All patients underwent BCS or primary mastectomy without neoadjuvant treatment and proportions per year were calculated. Logistic regression analysis with adjustment for period, age, nodal status and tumor size was performed to determine the impact of histology on the likelihood of undergoing BCS. A total of 152,574 patients underwent surgery in the period between 1990 and 2010, of which 89 % had IDC and 11 % had ILC. In the group of IDC with pT1 and pT2 tumors combined, 54 % underwent BCS compared with 43 % of patients with ILC (p <0.0001). The proportion of patients with IDC treated by BCS increased from 46 % in 1990 to 62 % in 2010. The BCS rate among ILC patients increased from 39 % in 1990 to 48 % in 2010. Patients with ILC were less likely to undergo BCS compared with patients with IDC (odds ratio 0.69; 95 % confidence interval 0.66-0.71). The incidence of BCS for patients with IDC or ILC is rising in The Netherlands. However, the increase of BCS is less explicit in patients with ILC, with a higher chance of undergoing mastectomy compared with patients with IDC.