Abstract P5-18-22: Long-term survival of patients with HER2 metastatic breast cancer treated by targeted therapies

Purpose: HER2 targeted therapies have substantially improved outcomes of patients with HER2 positive metastatic breast cancer (MBC). Medical records of patients with HER2 positive MBC achieving long survival were reviewed to describe their clinical characteristics and to assess whether curability is possible. Patients and methods: One thousand and seven hundred patients with MBC were treated between 01/01/2003 and 31/05/2012 in the 5 hospitals from the Franche-Comte region. All 217 patients with HER2 positive MBC region were retrospectively studied. Results: Among this population of HER2 positive MBC, 56 patients (26%) survived longer than 5 years. The characteristics of these long survivors were the following: median age at diagnosis was 55 years old (range, 33–87); 20 patients (35,7%) were metastatic at presentation; 20 patients (35,7%) had received adjuvant chemotherapy; the median disease-free interval was 17 months; brain, liver, lung, bone metastases were observed in 4 (7%), 19 (34%), 13 (23%), 23 (41%) in cases at occurrence of metastatic disease, respectively; tumours were hormonal receptors positive in 39 cases (70%) of these patients. A total of 16 (29%), 7 (12,5%), 7 (12,5%) and 26 (46%) cases had received 1, 2, 3 or more lines of chemotherapy at metastatic setting. The proportion of HER2 targeted treatment was 79%, 61%, 50% in first, second and third line, respectively. All patients received trastuzumab or lapatinib for their disease and 18 patients (32%) were given an anthracycline containing regimen. There were 7 complete response (CR), there were all observed after one line of chemotherapy based on trastuzumab combined with a taxane in all cases. Among these 7 patients, all continued trastuzumab after CR and all RH+ patients received hormonotherapy after CR. Among these 56 patients, 35 (62,5%) were still alive at the date cutoff in 31/05/2012. Conclusion: A significant proportion of patients with HER2 positive MBC were long survivors. Prospective clinical trials in this subset of patients should take into account this high number of patients with favorable outcome to achieve conclusion in term of survival. Can one consider the curabiblity of some MBC patients with HER2 overexpression? Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-18-22.