ConclusionsIn the trastuzumab era, patients with her2+ and hr+ early breast cancer have similar outcomes, while tn patients experience a significantly worse os than either of the foregoing groups. Outcomes for her2+ patients may differ by er and pr status. Trastuzumab was underutilized in this cohort. KEY WORDSher2-positive breast cancer, survival, trastuzumab, adjuvant

age at onset, large mean tumor size, high grade and higher incidence of node positivity at presentation compared to what is expected based on tumor size. TN status remains an independent risk factor for distant relapse and survival, with a rapid rise in distant relapse in the first three years after diagnosis 2,7 . additionally, patients with TN breast tumors have an increased propensity for lung and brain metastases, making these tumors especially challenging to treat.Molecular classification of breast cancer has further improved our understanding of the biology of this disease. Five intrinsic molecular subgroups of breast cancer have been described, including luminal a, luminal B, Her2-enriched, normal-like, and basal-like breast cancer (BLBC) 8 . Compared to the highly estrogen-sensitive luminal a subgroup, BLBC has significantly worse clinical outcomes with decreased recurrence free and overall survival 8 . BLBC and TNBC share many pathological, molecular, and clinical features, but they are not equivalent. Studies have demonstrated that not all TNBCs are basal-like 9,10 and not all BLBCs have a TN profile 10 . a study analyzing molecular markers differentiating TN tumor subtypes indicated that only 71% of TN tumors (n = 172) had a basal phenotype 9 . research has also suggested that non-basal TNBC may have a more favorable prognosis 8,10,11 .a "five marker" method has been proposed, combining the absence of er, Pr and Her2 with the expression of either epidermal growth factor receptor (eGFr) or cytokeratin (CK) 5/6, to differentiate BLBC from TNBC. While this method has demonstrated specificity for basal-like cancers, the definition has not been uniformly accepted. In the absence of a consensus regarding the optimal method of defining the basal-like subgroup of patients, TN status remains a clinical surrogate.Unlike patients with er/Pr-positive or Her2-overexpressing subtypes, systemic treatment options for patients with TNBC are limited to cytotoxic chemotherapy due to a lack of clinically-validated molecular treatment targets 12 . Standards have not ABSTRACTTriple-negative breast cancer (TNBC) has a poor prognosis compared to other subtypes and lacks common therapeutic targets, including Her2 and the estrogen and progesterone receptors. The clinicopathological heterogeneity of the disease and limited treatment options make clinical management particularly challenging. Here we present the results of a survey of Canadian clinical oncologists regarding treatment of TNBC, and review recent and ongoing clinical research in this area. Our survey results show that the majority of respondents use a combination of anthracyclines-taxanes as adjuvant therapy for early TNBC. For the first-line treatment of metastatic TNBC, most clinicians recommend taxanes, while single agent capecitabine and platinum-based therapies are more common for subsequent lines of therapy. Despite the ongoing development of novel targeted therapies, chemotherapy remains the mainstay of treatment for TNBC.

This article provides an overview of recent advances in chemotherapy that may be used for the treatment of patients with locally advanced or metastatic breast cancer (mbc). Key phase ii and iii trial data for eribulin mesylate, ixabepilone, and nab-paclitaxel, published since 2006, are discussed on the basis of recency, depth, and quality. Eribulin mesylate is the first monotherapy to significantly increase overall survival in patients with pretreated mbc, but nab-paclitaxel offers a novel and safer mode of delivery in comparison with standard taxanes. By contrast, the use of ixabepilone will be limited for now, until the associated neurotoxicity can be better managed. Alongside a brief overview of the other major chemotherapies currently in use, we have aimed to provide a Canadian context for how these novel agents may be integrated into clinical practice.