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=2,513) at 7 years, the DFS rate was 75.8% [95%CI 74.0%-77.6%], and the MFS rate was 84.1% [82.5%-85.6%]. According to hormonal status, the 7-year DFS rate was significantly higher for HR+ than for HR- patients [80.0% vs . 68.6%; p <0.001], and the 7-year MFS rate [87.9% for HR+ vs . 77.5% HR-]. According to nodal status, the 7-year DFS rate was significantly higher for N- than for N+ patients [86.7% vs . 66.4%; p <0.001], and the 7-year MFS rate [94.7% for N- vs . 74.9% for N+].
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.