Relapse rate after adjuvant trastuzumab in the northeast of Italy: Preliminary data from a multicenter observational study in a clinical setting. J Clin Oncol 30, 2012 (suppl; abstr 586)

Background: Relapse Rate (RR) after Adjuvant Trastuzumab (AT) reported in clinical trials is between 15 and 21%. Information on RR and clinical behaviour of HER2-POS metastatic disease after AT outside clinical trials is limited. At ASCO Meeting 2010 RR was reported 8% (Abs 1080) to 10% (Abs 684), with a Survival Post Progression (SPP) of 8.8 and 5.7 months, respectively. It is useful to increase informations about metastatic HER2-POS disease after AT, outside clinical trials Methods: HER2-POS consecutive cases treated with AT in 6 Hospitals of North East Italy were anonymously collected and merged. The following data were analyzed: Stage, ER/PgR Status, Chemotherapy regimens (CHT) , follow up, RR, Disease Free Survival (DFS), Overall Survival (OS) and SPP Results: The number of patients was 413, median age 55 (24-84). Anatomic Stage was I in 39.7%, II in 40,3%, III in 24.4%. ER/PgR neg cases were 164 (41.6%). Given CHT were Anthra-based 33.4% and Anthra-Taxane 54.5%. At a mean follow up of 35 months (7-115) RR was 10.8% (45 cases), with a mean DFS of 23.8 months (3.2-74). Among relapsed patients, 37/45 (82.2%) had ER/PgR neg tumors. One patient died NED for CHF and 22 for metastatic disease, with a mean OS of 37.1 months (10.2-87.9). Mean SPP was 17.8 months. According to DFS <12 mos , >12<24 and >24, mean OS was 31.3, 31.7 and 56.12(p=0.03) months; SPP was 24.2, 14.4 and 17.8 months, respectively Conclusions: In our experience RR after AT is lower than in published Phase III clinical trials. ER/PgR neg status seems a negative prognostic factor (82.2% in the relapsed population vs 41.6% overall). OS is similar for patients relapsed within 24 months but SPP is 10 months longer in very early relapses. Relapse after 2 years is correlated with a long OS (nearly 5 years), with SPP shorter vs early relapse (17.8 vs 24.2 months). Our preliminary results suggest different disease behaviors in relapsed HER2-POS Breast Cancer after AT, with different DFS and SPP, suggesting a different effect of further therapies. Considering the small RR, the study target accrual is proceeding to collect up to more than 1000 AT treated patients, including post-progression treatments, not available at the moment