149P Clinical outcomes in ER+ breast cancer patients with recurrence score 26-30-guided therapy: Real-world data

BackgroundThe 21-gene Recurrence Score (RS) assay is a validated prognosticator/predictor of chemotherapy (CT) benefit in early-stage estrogen receptor (ER)-positive HER2-negative breast cancer (BC). Based on previous retrospective trials, patients with RS<31, chemoendocrine therapy (CET) was not superior to endocrine (ET) alone. Recent prospective trials confirmed non-inferiority ET vs CET RS<26. Data regarding CT the RS 26-30 group are sparse.MethodsThis exploratory analysis Clalit Health Services (CHS) registry included all CHS ER+ BC and who underwent testing between 1/2006 12/2016, determined 7-year Kaplan-Meier (KM) estimates for overall survival (OS), distant recurrence free (DRFS), BC-specific mortality (BCSM).ResultsThe 394 node-negative (49% CET-treated, 51% ET-treated) 140 node-positive (62% 38% ET-treated). For patients, median (IQR) follow up 7.8 (5.8-11.1) years, KM OS, DRFS, BCSM were statistically significantly different groups; rates (95% CI) group, 97.9% (94.4-99.2%) (94.6-99.2%) 91.5% (86.6-94.7%) 91.2% (86.0-94.6%) 0.5% (0.1-3.7%) 1.6% (0.5-4.7%) BCSM. 8.2 groups OS DRFS; these respective 96.3% (89.2-98.8%) 93.8% (82.3-98.0%) 89.4% (80.9-94.4%) 78.0% (64.3-87.5%) DRFS. The differed treatment (P=0.024, log-rank test); rate 1.3% (0.2-8.6%) 6.2% (2.0-17.7%) group.ConclusionsIn 26-30, had no significant effect clinical outcomes; however, associated reduction BCSM, without DRFS.Legal entity responsible studyRotem Stemmer.FundingOncotest, Exact Sciences.DisclosureO. Rotem: Financial Interests, Personal, Invited Speaker: AstraZeneca, Boehringer Ingelheim, BMS, MSD, Novartis, Pfizer, Roche, Takeda, Teva; Advisory Role: NucleaiMD, Edocate. I. Kuchuk: Medison; Sponsor/Funding, Travel support: Medison, Pfizer. S. Paluch-Shimon: Institutional, Board, board invited speaker honoraria: Roche , sciences, Eli Lilly; Other, Pfizer Novartis AstraZeneca; board, speaker's bureau, consultancy: Personal Research Grant, grant an RFP independent research put out by SPCC Pfizer: (Shared Progress Cancer Care). R. Yerushalmi: Principal Investigator: Gilead Sciences, Lilly, AstraZeneca. A. Sonnenblick: Lilly MSD AstraZeneca Progenetics; travel/accommodation expensess: Neopharm, Celgene expenses: Roche; Teva, Grant: . E. Nili Gal Yam: Honorarium: H. Goldvaser: Rhenium, Oncotest, MSD; Gilead. Bareket-Samish: Writing Engagements: Can-Fite, L. Soussan-Gutman: Full or part-time Employment: Genomic Health. Stemmer: BioLine RX, BMS Halozyme Clovis Oncology CTG Pharma, Exelexis, Geican, Moderna, Stocks/Shares, stocks/options: DocBox MD, Tyrnovo, VYPE, Cytora, Can-Fite. All other authors have declared conflicts interest. sparse. MethodsThis (BCSM). This ResultsThe group. ConclusionsIn In