Treat Er(+)Ight: Canadian Prospective Observational Study In Post-Menopausal Hir+Fier2(-) Advanced Breast Cancer Women-First Interim Analysis (Ia).

1067Background: Treat ER+ight is the first Canadian real-world study enrolling patients (pts) previously exposed to NSAI therapy and currently receiving endocrine therapy (ET) alone or in combination with targeted therapy (ET+TT). Methods: This first planned IA describes baseline parameters and adverse event (AE) prevention strategies adopted by 16 centers since Feb 2016 upon enrolling pts initiating ET or ET+TT. Results: See Table.Conclusions: This IA suggests that pts initiating ET+TT are younger, have a better ECOG status, mostly visceral disease and receive more prophylactic/proactive AE prevention therapies. Insights into real-world dosing and sequence will be presented. Clinical trial information: NCT02753686.Baseline characteristicsOverall(n=72)ET(n=34)ET+TT(n=38)Age, median yrs (range)69.0 (37.0 – 88.0)71.5 (37.0 – 88.0)65.0 (39.0 – 80.0)Family history of BC, n (%)26 (36.1)11 (32.4)15 (39.5)ECOG 0-1, n (%)46 (63.9)19 (55.9)27 (71.1)Time from diagnosis, median yrs (range)---Primary5.1 (0.1-37.4)5.0...