Publication Year: 2000 Visited: 71

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Relationship Between erbB-2 Status and Neoadjuvant Chemotherapy Response is Dependent on Anthracycline Dose Intensity. Thierry Petit, Jean-Pierre Ghnassia, Jean-François Rodier, Christian Borel, Anne Escande, Ricardo Mors, Jean-Claude Janser, Pierre Haegelé, Paul Strauss Cancer Ctr, Strasbourg, France.

Objective : The NSABP B-11 and SWOG studies indicated that the addition of anthracyclines in adjuvant treatment improved clinical outcomes of patients (pts) with erbB-2 positive tumors (T). The CALG 8541 study suggested that pts with erbB-2 positive T might benefit from dose-intensive CAF. Focusing on the neoadjuvant setting, we evaluated the predictive value of a tumor's erbB-2 status for chemotherapy response, and the effect of anthracycline dose intensity on this predictive value. Patients : We assigned neoadjuvant chemotherapy to 79 pts with newly diagnosed stage II or non-inflammatory stage III breast cancer. ErbB-2 status was evaluated by immunochemistry on microbiopsy before chemotherapy (monoclonal antibody CB 11, Novocastra). Before 1996, 39 pts (Group A) were treated with FEC50 (epirubicine 50mg/m²), and 40 pts (Group B) with FEC100 (epirubicine 100mg/m²) after 1996. Overall response rate (ORR) was evaluated through clinical, ultrasound, and mammographic measurements. Pathological complete response (pCR) was evaluated by tumor excision and axillary node resection after 6 cycles. T characteristics were : median pre-treatment size, group A= 42 mm (25-80), group B= 40 mm (25-90) ; clinically positive axillary lymph nodes, group A= 59%, group B= 47% ; SBR III, group A= 35%, group B= 26% ; hormonal receptors negativity, group A= 31%, group B= 29%. Results : ErbB-2 was overexpressed in 27% of group A and in 32% of group B tumors. In group A, ORR=75% and pCR=10% for erbB-2 negative T, ORR=0% and pCR=0% for erbB-2 positive T. In group B, ORR=72% and pCR=10% for erbB-2 negative T, ORR=100% and pCR=28% for erbB-2 positive T. Conclusion : In group A, erbB-2 negative T had a significant better ORR than erbB-2 positive T (p<0.001). In group B, there was no difference in ORR between erbB-2 negative and erbB-2 positive T. ErbB-2 positive T treated with FEC100 had a significant better ORR than treated with FEC50 (p=0.001). There was no difference in ORR for erbB-2 negative T treated with FEC50 or FEC100. Our results are sufficiently noteworthy to merit further studies, given the implications for drug choice according to a tumor's erbB-2 status.