Lobular Breast Cancer

Abstract

Invasive lobular carcinoma (ILC) is the second most common type of breast cancer, with a unique pathogenesis and distinct clinical biology. These cancers display a characteristic loss of E-cadherin, and the vast majority are estrogen receptor positive (ER+), with a low-to-intermediate grade. These features generally portend a favorable prognosis, but there is a propensity for late recurrences and metastasis to atypical locations. These infiltrative tumors can be more clinically challenging than the more common ductal cancers. Their insidious nature can make them more difficult to diagnose, and they may show a differing response to standard therapies, keeping with the predominantly ER+ phenotype. Although ILC patients comprise a small minority in large breast cancer trials, most fundamentals of locoregional and systemic therapy presently remain shared between all cancer types. Recognizing the nuances of treating ILC remains important, and the recent discovery of novel mutations that are more frequently expressed in ILC holds promise for further investigations into lobular-specific targeted therapies. This review 3 figures, 8 tables and 50 references Key words: aromatase inhibitors, breast cancer, breast conservation, chemotherapy, E-cadherin, invasive lobular carcinoma, mastectomy, The Cancer Genome Analysis