Adjuvant Therapy for HER2-Positive Early-Stage Breast Cancer

Abstract

There is no preferred adjuvant chemotherapy regimen for HER2-positive early-stage breast cancer, but taxanes and/or anthracyclines must be part of the adjuvant chemotherapy regimen. In node-negative patients, HER2-positive tumors with a diameter of less than 0.5 cm (T1a) may receive chemotherapy plus trastuzumab. HER2-positive tumors with a diameter of 0.5--1.0 cm should be considered for adjuvant chemotherapy plus trastuzumab, and those larger than 1 cm require chemotherapy plus trastuzumab. All node-positive patients require chemotherapy plus anti-HER2 therapy. When chemotherapy is contraindicated, trastuzumab may be administered either alone or with endocrine therapy. Trastuzumab should not be administered with anthracyclines but should be provided concurrently with taxanes. ER positivity or negativity should not alter the decision regarding adjuvant trastuzumab if otherwise indicated. The preferred duration of trastuzumab therapy is 1 year. The addition of adjuvant pertuzumab to trastuzumab treatment prolonged disease-free survival in HER2-positive patients. This benefit was particularly evident in high-risk patients who were hormone receptor negative and node positive. In a randomized trial, 1-year neratinib use after 1-year administration of trastuzumab reduced the recurrence rate. This benefit was especially evident in ER-positive, HER2-positive disease. However, diarrhea was an important adverse effect.