Optimal use of anti-HER2 agents for early stage breast cancer

Breast cancers that overexpress HER2 or have amplification of the gene that encodes this progein are called HER2 positive and are sensitive to anti- HER2 therapies such as trastuzumab. Several pivotal trials demonstrated that the use of one year of trastuzumab, beginning with the taxane portion of adjuvant therapy, is likely superior to other approaches. Pertuzumab, which binds a distinctly different region of the extra-cellular domain of HER2 is known to further improve outcomes in the metastatic setting and do increase the rate of pathologic response when given pre-operatively. Whether it will become standard in the conventional adjuvant setting remains to be determined although a large randomized trial addressing this issue is completed. For low risk patients, paclitaxel and trastuzumab may be considered based on very low event rates in a non-randomized trial but it is possible that newer and less toxic approaches, such as the trastuzumab-DM1 linked agent, could be useful here. The impact of hormone receptor status on these decisions is also being explored at present.