ERBB2 and breast cancer: The primary objective of this study was to retrospectively evaluate the safety issues and adverse effects of using the TCHP regimen (docetaxel, carboplatin, trastuzumab, and pertuzumab) versus the TCP regimen (docetaxel, carboplatin, and trastuzumab) in older postmenopausal women that had nonmetastatic HER2-positive breast cancer in a retrospective setting.