Adjuvant trastuzumab: progress, controversies, and the steps ahead

Abstract

The major breast cancer story of 2005 was trastuzumab, a monoclonal antibody directed against the Her-2 oncoprotein, and how it greatly improves outcomes for women with HER2-positive early-stage breast cancer. With early results showing that use of the drug can prevent roughly one half of relapses, adjuvant trastuzumab has been approved, funded, and accepted as the standard of care in many Canadian jurisdictions. In the present brief report, we summarize the four major adjuvant trials, outline some key controversies, and suggest steps to provide more-effective and better-tolerated adjuvant systemic therapy for the relevant patient subgroup.

Figure 1

Adjuvant trastuzumab study designs. ac = doxorubicin–cyclophosphamide; t = docetaxel; h = trastuzumab; at = doxorubicin–taxane; auc = area under the curve; bcirg = Breast Cancer International Research Group; cmf = cyclophosphamide–methotrexate–5-fluorouracil; ct = chemotherapy; ec = epirubicin-cyclophosphamide; et = epirubicintaxane; fac = fluorouracil–doxorubicin-cyclophosphamide; fec = fluorouracil–epirubicin–cyclophosphamide; fish = fluorescence in-situ hybridization; ich = immunohistochemistry; ncctg = North Central Cancer Treatment Group; nsabp = National Surgical Adjuvant Breast and Bowel Project; hera = Herceptin Adjuvant Trial.