Abstract P3-15-02: Treat ER+ight Canadian prospective observational study in HR+ advanced breast cancer:2ndinterim analysis

Treat ER+ight is the 1st prospective observational study in Canadian postmenopausal women with HR+ HER2– advanced breast cancer currently receiving endocrine therapy (ET) alone or in combination with targeted therapy (TT) (NCT02753686). Methods: This pre-planned interim analysis describes baseline characteristics, treatment sequence, monitoring patterns, patient-reported quality-of-life (QoL) and resource utilization of patients enrolled in ET and ET+TT cohorts within the 1st 3 months of therapy. At data cut-off (13Mar917), 100 patients were enrolled from 24 sites since Mar916. Results: Enrollment therapy (%): everolimus+exemestane (35), fulvestrant (15), palbociclib + letrozole (15), tamoxifen (14), exemestane (7), palbociclib+fulvestrant (7), letrozole (4) and palbociclib+exemestane (1). Follow-up visits with physician after therapy initiation ET, ET+TT (%): week 2 (5, 47), month 1 (71, 67), month 3 (43, 31). Numerical differences were observed in EORTC QLQ C30 and BR23 global health status/QoL, functional and symptom scale scores between ET and ET+TT cohorts. Mean changes in transformed scores from baseline to month 3 were generally similar between cohorts however 9therapy side effects9 symptom item worsened in ET+TT cohort (P = 0.031, Wilcoxon rank sum). Resource utilization in between scheduled visits during 1st 3 months of therapy was similar between cohorts for physician/radiology, hospitalizations and ER visits however patient calls to supportive care nurse was increased in ET+TT cohort (P = 0.008, Fisher9s exact). Treatment discontinuation rate (20%) was similar between cohorts with progression as predominant reason for initiating next therapy. Chemotherapy (CT) was the most frequent subsequent therapy and represented 1st line metastatic CT for majority of patients. Conclusions: ET+TT patients were younger, had better ECOG, more visceral disease and 60% received everolimus+exemestane with Citation Format: Dent S, Califaretti N, Doyle C, Ferrario C, Chouinard E, Kulkarni S, Roy J-A, Perri SR, Chia S. Treat ER+ight Canadian prospective observational study in HR+ advanced breast cancer: 2nd interim analysis [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-15-02.