Retrast: Retreatment after adjuvant trastuzumab—Our regional southern Italy experience.
e11526 Background: Trastuzumab (T) is the standard of care for pts with HER2+ve BC. Relapse after adj T remains a rare event. Since the large use of T in adj setting, becomes crucial to evaluate advantages of retreatment with T for pts who relapsed after treatment in early stage. There is still lack of clinical evidence and poor data from CT to say that there is a benefit in T re-exposure after relapse following adj T. Methods: Since Jun 2006 and Dec 2011, we reviewed pts with early BC treated with T in adj therapy, relapsed and re-treated with T in first line therapy, in 10 departments of medical oncology in Sicily. We aimed to study feasibility, responses and treatment outcome. Results: 62 pts with HER2+ve fulfilled the criteria for this analysis and 47 were evaluated. Pts had a median age of 53 ys (29-79). ER/PgR-ve cases were 16 (34 %). Ki67 was > 20% in 34 pts (74%). 31 pts (64%) had >3 nodes+ve. All the pts received adj therapy with anthra+/-taxane. 55% of pts had >2 metastatic sites. 12 (25,5%) pts were revalued for HER2: 10 pts confirmed 3+ and two pts 2+ were FISH+. Median time from diagnosis to relapse was 25 mos (7 – 36). Median time from last dose of T to relapse was 10 ms (2 – 35). 33 (70,2%) pts and 14 pts (29,8%) had early (< 12 ms) and late progression (≥ 12 ms) respectively after adj T. First line of therapy was T in combination with mono/polychemotherapy in 42 pts (89,3%) and 5 pts (10,6%) respectively. 27 pts (57,4%) had objective responses (CR 5, PR 22) and 7 pts (14,8%) stable disease. 13 pts (27,6%) had progression: all of these pts had early progressive disease after adj T, 9 pts (69,2%) had Ki67>20%, 5 pts (38,4%) were ER/PgR-ve and 8 pts (61,5%) ER/PgR+ve. Median TTP was 4 mos (range 2-7). Median TTP for early and late relapses pts were respectively 3,7 and 4,8 mos, (p = 0,4). Median OS from relapse to death was 23 mos (r 12 – 37). LVSD G1 (EF < 60-50%) was observed only in 7 pts (14%). Conclusions: Our data confirm the feasibility and safety of treatment with T after adj T therapy and is active for a disease control rate in 72,4% of cases. These results demonstrate that relapses after adj T occurred early (<12 ms) in 70% of pts. However pts with primary resistance (27,6%) should be well categorized using biomolecular markers to receive up-front drugs that overcome the resistance to T.