R. Charles Coombes1, Robert Paridaens1, Jacek Jassem1, Cornelis JH van de Velde1, T. Delozier1, Steven Jones1, Emma Hall1, Lucy Kilburn1, Claire Snowdon1, Judith M. Bliss1
1Imperial College, London, United Kingdom; University Hospitals Leuven, Leuven, Belgium; Medical University of Gdansk, Gdansk, Poland; Leiden University, Leiden, The Netherlands; Centre François Baclesse, Caen, France; US Oncology Research, Houston, TX; Institute of Cancer Research, Sutton, United Kingdom
Tóm tắt
LBA527 Background: We have previously shown that switching to exemestane (E) after 2–3 years tamoxifen (T) improves disease free survival (DFS) in postmenopausal (PM) women with early breast cancer (BC). We report results with 95% of patients (pts) having ≥3 years follow-up. Methods: 4724 PM pts (2352 E vs 2372 T) with ER +ve/unknown unilateral BC, disease-free after 2–3 years T, were randomized to continue T or switch to E to complete a total of 5 years adjuvant endocrine therapy. 122 pts (56 E vs 66 T) originally reported as ER unknown were later found to be ER −ve. In addition to intention to treat (ITT), we repeated analyses excluding ER −ve pts. Adverse events (pre relapse) by treatment received were analysed on treatment (TRT) and also including follow-up (TRTFU). In safety analyses P < 0.01 was taken as significant due to multiple testing. Results: With median follow up of 58 months there were 808 first events (disease relapse, contralateral breast cancer (CLBC), intercurrent death) and 483 deaths. See table for unadjusted hazard ratios (HR). In ER +ve/unknown pts, adjusting for pre-specified prognostic factors of nodal status, chemo use, HRT use, gave HR for DFS of 0.74 (0.64, 0.85); p < 0.0001 and for overall survival (OS) of 0.83 (0.69, 0.99); P = 0.04. There were 145 intercurrent deaths (65 E vs 80 T), including deaths from cardiac (14 E vs 13 T), vascular (17 E vs 11 T) and other cancers (20 E vs 35 T). No statistically significant differences in myocardial infarctions, angina, or cerebrovascular accidents were observed. In T pts there were more thromboembolic (TRT p = 0.006, TRTFU p = NS) and serious gynaecologic events (TRT p < 0.001, TRTFU p < 0.001) and less fractures (TRT p = NS, TRTFU p = 0.003). Conclusions: Switching to E following 2–3 years of T significantly improves DFS, reducing chance of first event, CLBC and distant recurrence. In ER +ve/unknown pts, the switching strategy with E significantly reduces the risk of dying. [Table: see text] [Table: see text]
