Tolerability and Efficacy of Adjuvant T-DM1 in Patients with HER2 Positive Breast Cancer After Incomplete Pathological Response to Neoadjuvant Chemotherapy Including Anti-HER2 Agents.

Inclusion Criteria

• •Histological diagnosis of HER2 positive breast cancer;
• •Presence of invasive residual disease on T or N after neoadjuvant chemotherapy including anti-HER2 agents
• •Treatment with T-DM1 in the adjuvant post-neoadjuvant setting, in case of positive hormone receptors in combination with adjuvant hormone therapy. Complementary radiotherapy will be allowed as per lines guide;
• •Availability of adequate information regarding treatment with adjuvant T-DM1 in accordance with the objectives of the study;
• •Written informed consent for the prospective part and, if possible, for the recruited patients retrospectively