Up to 20% of breast cancers lack receptors for estradiol, progesterone and human epidermal growth factor receptor 2, triple negative breast cancer. Negativity for these receptors is not completely nor consistently defined. ImmunoHistoChemical/In Situ Hybridisation determined triple negative breast cancer is strong but incomplete compared to the molecular intrinsic basal like subtypes one and two, but also includes non-basal like subtypes. Most triple negative breast cancers are of the histological IDC-NOS type. Triple negative breast cancer in general has unfavourable clinical and prognostic characteristics and is most frequently diagnosed in young women and women with (germline) mutations in BRCA1. Therefore, triple negativity may be an indication for genetic testing of germline BRCA mutations. Lymphocytic infiltration of triple negative breast cancer correlates with a less detrimental prognosis. Triple negative breast cancers often lack mammographic micro calcifications.
Regardless of type of primary surgical treatment, patients with triple negative breast cancer are more at risk for local/regional recurrence than other types. But there is no reason for local/regional treatment or indications for (neo) adjuvant systemic therapy beyond accepted guidelines for breast cancer in general. The mainstay of (neo) adjuvant medical treatment of early triple negative breast cancer is combination (sequential) chemotherapy with anthracyclines and taxanes. Alternatives are pegylated liposomal doxorubicin or classical cyclophosphamide, methotrexate 5-fluorouracil. In triple negative breast cancer with BRCAness, platinums may replace taxanes in neoadjuvant treatment to optimise the pathologic complete response rate. Several targeted therapies proved to be effective in metastatic triple negative breast cancer, but to date there are no such validated treatments for early disease. Besides targeted therapies, immune modulatory strategies for well characterised immunogenic triple negative tumours (i.e. with different grades of lymphocytic infiltration) are promising.
(BELG J MED ONCOL 2016;10(1):7–14)