Recurrence of HEr2+ pAtients: evaluation of Long term outcome In patients receiving trastuzumab TherapY

Abstract Background Despite improved prognosis of HER2+ eBC since the introduction of trastuzumab in the adjuvant setting in 2006, disease recurrences still occur in some patients after a few years. We aimed to describe in real life the long-term follow-up to assess disease-free and metastasis-free survival of patients with HER2+ eBC treated with adjuvant trastuzumab. Methods This was a multicenter, retrospective, cohort study assessing HER2+ eBC patients diagnosed between 2009 and 2010 and treated with adjuvant trastuzumab. Data were collected from patient’s medical charts. Disease-free survival (DFS), and metastatic-free survival (MFS) were evaluated in the overall population and within subgroups according to hormonal and nodal status. Results In the overall population (n=2,311) at 7 years, the DFS rate was 76.3% [95%CI 74.5%-78.2%], and the MFS rate was 84.2% [82.6%-85.8%]. According to hormonal status, the 7-year DFS rate was significantly higher in hormone-receptor positive (HR+) than hormone-negative (HR-) patients [80.5% vs . 69.2%; p <0.001 ], and the 7-year MFS rate [88.0% for HR+ vs . 77.7% HR-]. According to nodal status, the 7-year DFS rate was significantly higher for N- than for N+ patients [87.2% vs . 66.8%; p <0.001], and the 7-year MFS rate [94.7% for N- vs . 74.9% for N+; p <0.001]. Conclusions Despite introduction of adjuvant trastuzumab, prognosis of HER2+ eBC is still a matter above all in subgroups associated with a higher risk of disease recurrence. Our real-world study pointed out a particularly aggressive profile of N+ and HR- subgroups and the need for more efficient approaches for these particular group of patients.