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.

Patients affected by will be included in the study and analyzed HER2 positive breast cancer with residual invasive disease after neoadjuvant chemotherapy, treated consecutively with adjuvant T-DM1 at the various Italian oncology centers.

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

Exclusion criteria

• Concomitant treatments with other biological agents;
• Absence of clinical data that allow the correct analysis of the primary and secondary objectives;
• Patients with a history of other malignant neoplasms;
• Contraindications to the use of T-DM