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Found 1 Presentation For Request "228P"
228P - Pathologic response to neoadjuvant antiher2 therapy in HER2 equivocal overexpression with FISH amplification
- Serafin Morales (Lleida, Spain)
Abstract
Background
Pathologic response to neoadjuvant therapy is strong correlated with high HER2 expression, but the patients with HER2 equivocal overexpression and amplification with FISH are considered as HER2 positive and received the same therapy. We need to know the clinical course in this subset of patients and the benefit of the antiher2 standard therapy.
Methods
A serie of 71 early or locally advanced breast cancer patients with HER2 equivocal overexpression and FISH amplification who received neoadjuvant treatment with chemotherapy and antiHER2 drugs were analyzed their complete pathological response (pCR) and the clinical-pathological variables associated.
Results
Median age was 55 years (31-88), median tumour size was 30 mm (13-100) and 30 (42%) patients had nodal involvement. Median ki67 expression was 40% (4-95), 20 (28%) tumours were estrogen receptor (ER) negative and 41 (72%) positive. The ratio HER2/CEP17 was superior to 2 in 40/59 (67,8%). A total of 19/71 patients (27%) achieved a pCR. In the univariable analysis, only the estrogen receptor=0 (OR 0,193 IC 95% 0,061-0,611, p: 0,005), were correlated to pCR. We do not found any correlation with other variables and previous treatment with anthracyclines or pertuzumab plus trastuzumab. The pCR in ER negative was 52% and the subgroup with a ratio of HER2/CEP17 superior to 2.0 was the more responsive with a total of 80% pCR compared with 25% in the ratio inferior to 2.0. Conversely the pCR in ER positive was 17,6% % but the subgroup with a ratio of HER2 superior to 2.0 was only of 13,8% % of pCR compared with 26,7% in the ratio inferior to 2.0. We do not analyze the benefit on survival because the short median follow-up although the overall median survival of the global group was 148 months (IC 95% 125 to 171 months).
Conclusions
Patients with equivocal HER2 overexpression and FISH amplification have an overall pCR of only 28.8%. More than 70% have ER positive, and the proportion of pCR is only 17.6%. However, the subgroup with ER negative and high expression of HER2 / CEP17 ratio achieves a percentage of pCR that reaches up to 80%. Therefore, it is important to select these subgroups with a low proportion of pCR to offer other therapeutic alternatives.
Legal entity responsible for the study
Hospital Universitari Arnau de Vilanova de Lleida.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.