The differences in rate and duration of complete remission between HER2-positive and HER2-negative inflammatory breast carcinoma

Abstract

1106 Background: Inflammatory breast carcinoma (IBC) is rare but aggressive form of breast cancer. Up to 38% of IBC are HER-2+. According to literature, complete remission (CR) can be achived in more than 50% of patients with combinatination of chemotherapy and trastuzumab. However, trastuzumab is still not available in all countries. The aim of this study was to evaluate the rate and duration of CR to induction chemotherapy alone, without trastuzumab, in HER-2+ and HER-2- IBC pts and compare our results to literature data. Methods: The data were analized for 3,452 breast carcinoma patients registered at the Institute for Oncology and Radiology of Serbia (IORS) during one year. Among them, 281 pts had IBC, defined as pathologically confirmed skin lymphangiosis or BC with classical clinical signs of cancer mastitis. Responses have been evaluated clinically and by mammography after every 3–4 cycles of chemotherapy. CR was estimated as a complete disappearance of previously palpable breast tumour; no clinical and mammography signs of cancer mastitis; no enlarged regional lymph nodes and disappearance of all metastatic sites in stage IV. HER-2 status (IHC, Dako) was assessed in 88 patients (70.9%) and 25/88 (28.4%) were HER-2 3+. Results: We investigated 124 IBC pts with complete medical records. The overall incidence of IBC was 8.1%. Median age at diagnosis was 59 (ranges 35–81). The rate of CR is evaluated separately in subset of HER2+ and HER2- IBC. 100 pts received FAC induction chemotherapy (median number of cycles was 6) and remainder received CMF regimen (median number of cycles was 5), trastuzumab none. Only seven pts (5,6%), all treated with FAC achieved CR. Among them, four had HER-2 3+ (4/25; CR 16%) and three HER2 negative IBC (3/99; CR 3%). Median duration of CR in HER-2+ subset was 15 months (range 7–36+) and in HER-2- 18 months (range 7–101+). Conclusions: Our study shows that incidence of IBC in Serbia is higher than reported in the literature, 8,1% vs 1–4%. Also, it has been shown that very low percentage of IBC patients achieved CR after chemotherapy alone, esspecialy in HER-2- subset of IBC-only 3%, compared to 16% in HER-2+ group, even in the absence of trastuzumab, while the duration of CR in both groups were similar. No significant financial relationships to disclose.