Abstract

Background: Invasive lobular Carcinoma (ILC) is distinguished from Invasive Ductal Carcinoma (IDC) via negative E-cadherin staining. Accumulating data reveal different biological and clinical behavior of ILC in both early and metastatic breast cancer. Thus, IDC usually present as a solid mass while ILC tend to present as non-mass enhancement. Clinically, ILC tends to spread to the ovaries, peritoneum and meninges and is more resistant to chemotherapy. Current international guidelines do not consider ILC separately and do not issue distinct recommendations for this entity. In this work we compare the treatment approach to ILC and IDC t in pre and postmenopausal patients. Methods: A structured questionnaire was distributed to all breast cancer Oncologists in Israel. Two identical clinical cases were presented, the only difference being ILC or IDC histology. Results: about 80% (n=40) of breast cancer treating oncologists in Israel answered the questionnaire, different approach were noted between IDC and ILC in identical cases. For premenopausal patients with IDC stage II (T2N1MO) Luminal B, 61.0% of the oncologists recommended neoadjuvant chemotherapy (NACT) and 22% opted to upfront surgery, while for ILC only 26.8% initiated NACT and 39.0% chose upfront surgery. The difference was statistically significant (P0.014). In postmenopausal patients, there was numerically but not statistically significant difference between the treatment approaches. Conclusions: although international guidelines do not consider ductal and lobular histology separately, oncologists' treatment approach differs between premenopausal patients with IDC versus ILC histology.