Observational study to evaluate the pattern of trastuzumab (T) use and survival outcomes in HER2-positive (HER2+) early breast cancer (EBC): Regional Southern Italy experience.

Abstract

e11043 Background: HER-2 have shown to be over-expressed in 20-25 % of primary breast cancer, and is associated with poor prognosis. Several large, randomized studies have reported a significant reduction in the risk of recurrence when trastuzumab is administered with chemotherapy in EBC HER2+ cancer. The aim of this study is to identify the pattern of use of T and survival outcomes in HER2+ EBC in Sicily. Methods: This observational, multicenter, retrospective study was conducted in 11 oncology centers in Sicily during 2006-2010. Inclusion criteria: age ≥18 years, surgery for early breast cancer, diagnosis of invasive disease, HER2-positivity as defined by current guidelines, and treatment with T. Results: 569 patients (pts) were included. Surgical outcomes: quadrantectomy 58.1%, mastectomy 33.7% and tumorectomy 8.2%. Tumor stage: T1 50.6%, T2 37.9% and T3 11.5%. Histology: invasive ductal carcinoma 94.7%. Histological Grade: G3 55.6%. Node status: N0 52.6%, N1 27.3%, N2 12.5%, N3 6.7% and Nx 0.9%. Hormonal status: estrogen receptor positive 60.1% and progesterone receptor positive 47.3%. Proliferation: Ki67 ≥10% in 82.4%. Neoadjuvant and adjuvant T was administered in 11.9% and 93.4% pts, respectively. Sequential administration of T after adjuvant chemotherapy was the most common schedule. Cytotoxic agents used: anthracyclines 76.04%, taxanes 33.02% and both agents in combination 26.8%. Relapses were observed in 5.6% pts. The main metastatic sites were: liver 18.75%, bone 12.5%, lung 12.75%, brain 12.75%, locoregional and contralateral 12.5% and lymph nodes 9.4%. N positivity and hormone receptor negativity are significantly associated to relapse. Cardiac toxicity (LVEF reduction >10%) was observed in 3.5% pts. DFS at 25 months of FU was similar to that of HERA DFS at 23.5 months of FU. Conclusions: Our study confirms the efficacy and safety of T in early HER2+ breast cancer, although includes a better prognostic population. These data indicate a satisfactory level of adherence to the international guidelines in the management in HER-2 positive EBC, showing a significant improvement in DFS when T was added to adjuvant chemotherapy.