Relative Survival Benefit by Hormonal Receptor Status of Adding Trastuzumab to Neoadjuvant Chemotherapy in Breast Cancer Patients.

We found that the addition of trastuzumab to NAC improved relative survival benefit in HER2+/HR+ patients than in HER2+/HR- patients, even though the pCR rate increases were lower. Although pCR has been regarded as a surrogate marker for estimating long-term survival benefits after NAC, it alone may not translate into real long-term oncologic outcomes in particular cancer subtypes after trastuzumab-based NAC. Further longer-term evaluation of the objective survival benefit after NAC driven by a dual HER2 block according to HR status is warranted.