Chemotherapy refusal and subsequent survival in older women with high genomic risk, estrogen receptor–positive breast cancer.

520 Background: Patients with estrogen receptor (ER)- positive breast cancer and high-risk 21-gene recurrence score (RS) assay results benefit from chemotherapy, however some patients choose to decline chemotherapy. We evaluated factors associated chemotherapy refusal by older women high RS investigated the association of mortality. Methods: used National Cancer Database (2010-2017) retrospectively identify aged ≥65 years ER-positive, HER2-negative, (≥26) cancer. Women Charlson Comorbidity Index ≥1, stage III or IV disease, any unknown variables were excluded. who refused compared received Refusal trends analyzed using Cochrane Armitage test. Factors a multivariable regression model. Overall survival (OS) age treatment Kaplan-Meier Cox proportional hazards modeling. Results: 6827 met study criteria; 5449 (80%) 1378 (20%) refused. Relative those (median 71 vs 69 years; p < 0.05), more often insured Medicare (83% 80%; = diagnosed recently (2014-2017 2010-2013, 67% 61%; had lower grade tumors (grade 1 2 3, 57% 48%; frequently progesterone receptor-positive (68% 63%; radiation less (67% 71%; 0.05). Chemotherapy was significantly increasing (age 75-79 65-74 OR 1.61, CI 1.4-1.85; ≥80 3.24, 2.76-3.79) recent year diagnosis 2010-2013; 1.3 1.14-1.48). decreased 5-year OS for (92% 95%; 0.05) (85% 92%; but not (84% 91%; 0.07). Overall, when controlling patient factors, hazard death increased (HR 1.12, 1.04-1.2), stratified age. Conclusions: Among healthy genomic risk ER-positive cancer, in 65-79, did impact ≥80. Lower use may demonstrate pragmatic decision-making between physicians patients. Furthermore, routine assays be appropriate this group. More research is needed determine why 65-79 refuse whether remain satisfied these choices.