Clinical-pathologic features, long term-outcome and surgical treatment in a large series of patients with invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC).

A retrospective analysis on 1407 patients with invasive ductal carcinoma (IDC) and 243 invasive lobular carcinoma (ILC) was performed in order to compare the histological features, the immunohistochemical characteristics, the surgical treatment and the clinical outcome in the two groups.ILC seems to be more likely multifocal, estrogen receptor positive, HER-2 negative and to have a lower proliferative index compared to IDC. ILC, when treated with conservative surgery, required more frequently re-excision and/or mastectomy because of positive resection margins. No difference was observed in terms of 5-year disease free survival and local relapse free survival between the two groups, in the whole series and in the subgroup of patients treated with breast-conserving treatment.ILC can be safely treated with conservative surgery but a more accurate preoperative evaluation of tumor size and multifocality could be advocated, in order to reduce the re-excision rate.